CA1110608A - Weigh feeder system - Google Patents

Abstract

ABSTRACT OF THE DISCLOSURE

Disclosed herein is an automatically controlled weigh feeding apparatus including a container prefilled with a substance, a device for discharging the substance from the container at a controllable weight, apparatus for weighing the container and its contents and for producing an electrical signal proportional to that weight, a first amplifier for amplifying the electrical signal, a first analog-digital converter coupled to said first amplifier and a digital computer coupled to said first analog-digital converter for computing the weight of substance remaining in the container.
A second amplifier is coupled to said first amplifier and a ramp off-set circuit which is controlled by the digital computer inputs a second signal to the second amplifier means having a controlled stepping output applied as a second input signal to the second amplifier to maintain the output of the second amplifier within a given selected range of amplitude during one time cycle of operation. A second analog-digital converter interposed between the second amplifier and the digital computer. The digital computer is adapted to compute a corrective signal based on the signal received for controlling the discharge of the substance from the container.

Description

111~6~8 This application is a division of Canadian patent application Serial No. 267,641 filed December 10, 1976. -This invention relates to weigh feeding systems and it is particularly applicable to apparatus for feeding fluid-like material. Systems constructed according to the present invention are particularly adapted, among other possible uses, for accurately weigh feeding a wide variety of substances including dry materials regardless of whether the material is free-flowing, sluggish, or pressure sensitive; and ranging from amorphous powders to flakes, pellets, chunks and even fibers, as well as liquids.
Various control weigh feeding systems have been known in the past, as for example, the system disclosed in Canadian patent No. 1,005,143 and No. 1,021,437 issued Feb.
8, 1977 and November 22, 1977, respectively, to Ronald J.
Ricciardi et al. In accordance with these patents, there is provided a weigh feeding apparatus wherein the discharge rate of a fluid substance from a container is maintained at a pre-determined constant value. The container and its contents are weighed, and an electrical signal is produced which signal has an amplitude proportional to the weight of the container and its contents. This electrical signal, which varies as the contents of the container are discharged, is differentiated and applied to a comparator circuit together with a reference signal, wherefore the output of the comparator circuit may be used to control said discharge rate of the substance as it is fed from the container. The comparator output is applied to a signal generator for producing a motor drive signal for a DC
motor having its output shaft connected to drive a device for discharging the substance from the container. The signal ~-` 11106~18 1 ~

generator may comprise a pulsing circuit for controlling a pair of SCR's which are disposed in a rectifying bridge circuit connected between an AC voltage source and the input of the DC
motor. Accordingly, the speed of the motor is controlled by the pulsing circuit, which, in turn, is controlled by the algebraic sum of the output signal of a tachometer generator which is , coupled directly to the motor shaft, and output signal from the comparator. It can be stated that the above-described apparatus provides an accurate weigh feeding system, whereby the feeding rate may be maintained at a constant value, and wherein the predetermined feeding rate may be adjusted by adjusting the value of the reference signal source. -Additionally, the output of the weighing device may ', be applied to a pair of differential amplifier circuitsj along with a pair of reference voltage inputs, for determining when the contents of the container varies above and below desired maximum and minimum fill levels for the container. That is, circuitry is provided for automatically refilling the container when the weight of the substance therein reaches the desired minimum weight, and for terminating the filling process for the container when the fluid substance therein reaches the desired maximum weight. Such circuitry includes means for maintaining the dis-charge rate of the container at a constant rate equal to the instantaneous rate thereof immediately preceding energization of the filling device for the container. Particularly, the pair of differential amplifier circuits are coupled to a pair of relay driver circuits for controlling a relay circuit to energize the filling device when the substance in the container reaches the minimum weight, and for maintaining that filling device in an .
. . . ' -, ;)6~8 energized state until the container is refilled to its maximum desired level. The relay circuit is also coupled to the comparator circuit, for controlling the latter to produce a constant output during the refilling process for the container, thereby maintaining the discharge rate of the container at the value of the particular discharge rate thereof immediately preceding energization of the filling device.
As pointed out in said Canadian patents Nos.
1,005,143 and 1,021,437, in certain installations there exists a possibility of physical forces impinging upon the weigh feeder from an external source, such as wind or air currents, physical contact with the weigh feeder by operating personnel, or the like, for example. These forces cause the weigh feeder to move at a rate that is other than that resulting from the linear discharge of the contents of the container. Because such additional movement, i.e. acceleration, is an error and has no direct relationship to the actual discharge of material from the container, the control system could continue to perform its corrective function utilizing the erroneous output signal for comparison with the fixed set point reference signal derivative. The aforementioned patents disclose one means for preventing such excessive and abnormal movements of the weigh feeder scale from grossly affecting or disturbing the normal operation of the system to thereby prevent large excursions of the output feed rate.
The present invention is directed to new improved means for accomplishing the foregoing objectives, as well as additional objectives, as will become apparent as the description proceeds.

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106?8 Another feature of the present invention resides in the provision of a new and improved weigh feeder system, which is capable of controlling more operating parameters, which operates faster, which provides a faster responsive action, and which is more accurate as compared to the prior art systems. In addition, the feeder system of the present invention has a memory and is capable of taking into account past errors in the material flow rate and taking corrective action with respect thereto.
Also, the system is capable of disregarding extraneous material flow rate readings, which may be caused by such factors as noise, vibrations, or the like, for example.
In one form of the invention, we provide a new and improved weigh feeding apparatus characterized by a container for a prefilled substance having means for discharging the substance therefrom at a controllable rate. A scale system is ; provided for weighing the container prefilled with the substance and an electrical circuit serves to produce a first electrical signal proportional in amplitude to the weight, and a high gain amplifier amplifies the electrical signal. An analog-digital converter (ADC) is coupled to the amplifier and a digital computer is adapted to receive pulse signals from the ADC for computing and outputting a signal corresponding to the signal received. Digital-analog converter ramp offset means which is controlled by the computer outputs a controlled stepping signal, that is applied as a second input to the amplifier means to algebraically combine therewith. Each step corresponds to one time cycle of operation, thereby maintaining the output of the ~,, amplifier in a given preselected range of amplitude during one :`. ' ' .
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~ 6~8 time cycle of operation. The digital computer as another operation thereof computes a corrective signal based on the signal received, and means coupled between the computer and the means for discharging the substance from the container, serve to control the rate of discharge responsive to the corrective signal.

According to one aspect of the invention, the weigh feeder apparatus further comprises means for inputting into the digital computer a preselected feed rate/ and the computer is adapted to store in memory a series of signals recei~ed from the ~DC for each of the time cycles of operation and compute a corrective signal by comparing the signals received with the preselected feed rate. According to another aspect of the invention, the weight feeding apparatus further comprises ~n under-weight limit input means to the computer and an over-weight limit input means thereto. The computer, as one operation thereof, causes an underweight or an overweight light to energize when an underweight or an overweight condition exists for longer than some preset period of time. Further, according to another aspect of the invention, the digital computer computes the corrective siynal, while disregarding a preselected number of the signals received from the ADC, which exceed a set limit during one time cycle of operation, when computing the corrective signal.

The invention provides, accordin~ to another fo~m thereof, a new and improved weigh feeding apparatus which is characterized by a container for a prefilled substance and means far discharging the substance from the container at a controllabl .

l lil~6~8 rate of weight loss. A scale is provided for weighing the container prefilled with the substance and an electrical circuit !-is coupled to the weighing means for producing a first' electri,cal signal'proportional in amplitude to the weight , determined by the weighing means. A first amplifier ampli~ies th _ electrical signal and a first analog,-digital converter (ADC) is coupled to the first amplifier and outputs binary words to a digital computer coupled thereto. The digital computer, as one operation thereof, computes a first output signal correspond-ing to the weight of the substance in the container. A secon~d amplifier amplifies a signal received from the first amplifier and a second ADC is coupled to the second amplifier and outp~7ts a binary word signal to the digital computer. Digital-analog converter ramp offset means are provided which receive a signal from the digital computer and outputs a controlled stepping outpu~,which is algebraically combined with the input to the second amplifier, each step corresponding to one time cycle o~,operation, thereby to maintain the output of the second amplifier in a given preselected range of amplitude during one time cycle of operation. An input switch is provided to apply a preselected feed rate value to the computer. The , computer, as another operation thereof, stores in memory a series o said signals received from the second ADC for each of the time cycles of operation and computes a corrective signal by comparing the signals received with the preselected feed rate value. Coupling means interconnect the computer and the ~eans for discharging the substance from the container, whereby the c~rrective signal serves to control the rate of discharge of the s tance from the containee. A shaft enco~er is coapled to the ¦

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.~ . ' computer to allow vibration signals generated from the rotating machinery mounted on the scale to be corrected for in the computation of the feed rates.
In still another form of the invention there is provided a weigh feeding apparatus which includes a container for a prefilled substance, means for discharging the substance from the container at a controllable rate, means for weighing the container prefilled with the substance, and means coupled to the weighing means for producing electrical signals proportional to the weight determined by the weighing means.
In addition, the apparatus further includes an analog-digital converter for receiving the electrical signals, digital computer means coupled to the analog-digital converter for computing a corrective signal based on the signals received, and means coupled between the computer means and the means for dis-charging the substance from the container for controlling the rate of discharge responsive to the corrective signal. Further, this weigh feeding apparatus comprises, means for inputting into the computer means a preselected feed rate, said computer ~ 20 means being adapted to store a series of the signals received - from the analog-digital converter for a time cycle of operation and computing said corrective signal by comparing the signals received with the preselected feed rate, and said computer being further adapted to maintain the corrected signal constant during the time when a preselected number of the signals received from the analog-digital converter exceeds preselected upper or lower limits, during one time cycle of operation.
There has thus been outlined rather broadly the more important features of the invention in order that the ~ llV6~8 ~ailed description thereof that follows may be better understood, and in order that the present contribution to the art may be better appreciated. There are, of course, additional features of the invention that will be described more fully hereinafter. Those skilled in the art will appreciate that the conception on which this disclosure is based may readily be utilized as the basis of the designing of other structures for carrying out the various purposes of the invention. It is important, therefore, that this disclosure be regarded as including such equivalent constructions and methods as do not depart from the spirit and scope OL the invention.

One embodiment of the invention has been chosen for purposes of illustration and description, and is shown in the accompanying drawings forming a part of the specification, t wherein:

'' Fig, 1 is a block diagram of the weigh feeder system constructed in accordance with the concepts of the, present invention;

Fig. 2 is a graphic representation of the output voltage with respect to time of one of the amplifier circuits of the present invention;
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Fig. 3 is a graphic representation of the output ; of a controlled ramp offset circuit of the present invention; ~, Fig. 4 is a graphic representation of the output of a second amplifier circuit;

' Fig. 5 is a graphical representation of the actual measured feed curve as compared to the desired feed curve;
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6~8 Figure 6 is a graphic representation of the positional relationship of the shaft encoder with respect to the system noise;
Figure 7 is a graphic representation of the output of the second analog-digital converter with respect to time, ~efore correction for induced system noises;
Figure 8 is a graphic representation of the output of the second analog-digital converter with respect to time, after correction for induced system noises;
Figure 9 is a flow chart of the wait subroutine;
Figure 10 is a flow chart of the one second interrupt display subroutine;
Figure 11 is a flow chart of the derive subroutine;
Figuresl2A, 12B and 12C is a flow chart of the main routine of the computer;
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Figure 13 is a flow chart of the calculate sub-routine; and Figure 14 is a flow chart of the learn mode sub-routine. ¦-The weigh feeder system of this invention, as shown `diagramatically in Fig. 1, includes a feeder assembly indicated ~- generally at 10, which comprises a container 12 with a :, .
; discharge device connected thereto for feeding the substance 14 out of the container and through a discharge .~25 conduit 16. As illustrated, a DC motor 18, connected to a , ~ ~

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gear-reduction device 20 is provided for driving the discharge i device. The feeder assembly may comprise an auger mechanism as disclosed in detail in U.S. patent No. 3,186,602 issued June 1, 1965 to Ronald Joseph Ricciardi. The entire feeding assembly, including the container, the discharge device, the motor, and the gear-reduction device is mounted on a scale 22, which may comprise a structure as described in detail in U.S.
patent No. 3,494,507, issued February 10, 1970 to Ronald - Joseph Ricciardi.
In accordance with the invention there is provided ; a detecting device, as for example, a linear variable differential transformer (LVDT) 24, coupled to the scale for providing an electrical signal having an amplitude which is proportional to the weight of the container and its contents.
That is, as the contents of the container l2 are discharged, a relative movement occurs between the windings and the core of the LVDT, thereby causing a varying output voltage pro-portional to the varying weight of the container and its contents. Thus, as the substance is discharged from the , 20 container, the LVDT provides an electrical signal which varies in response to such discharge, which may, for example, be a DC voltage with a range of the order of from ~3 volts to ~6 volts when the material in the container drops from its upper level to its lower level. The signal from the LVDT is applied to a summing junction 26 by a conductor 28, ;~ through a resistor 30. Also, applied to the summing junction 26 is an offset potentiometer means 32, by a conductor 33 through a resistor 34, to render the signal from the LVDT symmetrical with respect to zero as measured at 38. The output from the summing junction 26 is applied to an amplifier 35, having a gain . . .

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~otentiometer 36, to produce an output signal at 38, which ranges, for example, from -10 volts when the container 12 is full to a ~10 volts when ~he container is empty, as shown by the curve in Fig. 2. The ou,tput signal from the am~l~fier 35 is applied to a conventional analog-digital converter (ADC~
40, by way of a conductor 42, wherein the offset ampli~ied ~VDT signal is measured a.nd digitalized and outputted as digital words, corresponding to the total scale weight, i.e. the quantity of material contained in the container 12. Any suitable type of ADC may be employed such as a 12 bit, Model No. 124-10 XW 3, as manufactured by Analog Devices, Inc.

In addition, the output signal from the amplifier 35 is applied through a resistor 43 to a second amplifier 44, having a feed back resistor 46, thereby to provide a gain of :
the order of about a 700 multiple. Applicants have found that a gain of this order is necessary in order to make the desired calculations later in the system, but with such a gain, the voltage would normally be too high, as a practical matter; for computational use, and therefore, a controlled ramp offset signal is also applied to a summing junction 47 by a conductor 48 through a resistor 49. This offset signal is provided by a ramp offset digital-analog converter (DAC) 50, which receives controlled digital words or binary bits and converts them to a.step-shaped signal, having a frequency correspondin~ to one time cycle of operation of the process system, as shown by the curve in Fig. 3. This ramp offset functions in cooperation with the amplifier 44 so that a controlled quantity is subtracted from the input to the amplifier, wherebv dur g one tlme oycle of operation the o~tput from the .' : - .

~ilO6~8 amplifier 44 gradually decreases from about ~5 volts to about -5 volts. The ramp offset 50 is a fast acting electronic servo (typically 50 microseconds), and is controlled so that between time cycles of operation its output is adjusted one step as shown in Fig. 3. Thus, at the beginning of the next succeeding time cycle, the output from the amplifier 44 is again about ~5 volts as shown in Fig. 4. Any suitable type of ramp offset DAC may be employed, such as a 14 bit Model ZD354Ml, having a resolution of 1 part in 10,000, as manu-factured by Zeltex, Inc., for example. The amplifiers 35 and 44 may be of any suitable type such as Model OPO5EJ, as manufactured by Precision Monolithics, Inc., for example.

The output from the amplifier 44 is applied to a conventional 12 bit analog-digital converter (ADC) 52 by a conductor 54, wherein the output signal from the amplifier is measured and digitalized. The output from the ADC is in the form of digital words corresponding to the scale weight, but greatly amplified.

A binary number system is employed as tl~e-code for information handling because of certain advantages hereinafter brought out. Thus, as seen in Fig. 1, the weigh feeder system is provided with a digital computer 56, which includes processing, memory and control systems. Any suitable digital computer may be employed such as a micro processor Model IMP16C/300 and memory Model IMP16P/004P, as manufactured by National Semiconductor Corp., for example. r Still referring to Fig. l, a plurality of inputs are plied to the processor to control the same. A aonventional !

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16~8 off-on switch 58 serves to control the main power supply to the processor. A switsh 60 is provided whereby the refill sequence may be automatically actuated (switch in "auto") when product level reaches low level, or at any product level (switch in "manual") or, the refill sequence may be bypassed (when switch is in "bypass"). The refill sequence is a procedure wherein the motor speed will not lockout for refill thereby actuating the refill controller until the computer first senses that the scale is undisburbed by foreign influences and secondly, senses that the feed rate agrees with the set feed rate.
Input switch 62 serves to convert the system between gravi-metric control and volumetric control, as desired. This will be explained more fully hereinafter. A reset total push button switch 64 serves to reset the processor for an entirely new batch of data. Also, there is provided a scale weight switch 66, that inputs into the processor the scale weight, S, which is determined by the size or model of the feeder assembly 10 being employed in the particular installation. This factor --is set once and is not adjusted unless a new model or size of feeder assembly is installed.
A motor speed input switch 67 is provided, which is set by the operators at a preselected percent in the range between 0% to 100%, to input into the processor the desired operating speed of the motor when operating volumetrically.
Input switch 68 is actuated by the operator to input the desired feed rate R (LBS./HR) into the processor.
This is a 16 bit digital word, stored in memory, that represents ` the desired slope of the feed line or curve 70, Fig. 5. Input .

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`~ 06~8 switch 72 is also actuated by the operator to input the under-weight set point into the processor memory. It represents the selected minimum limit of the feed rate range, as is indicated by the dotted line 74 in Fig. 5. This limit is expressed as a percentage of from 0 to 9.99~ below the desired feed rate R~
Input switch 76 inputs the overweight set point into memory.
It represents the selected maximum limit of the feed range, as is indicated by the dotted line 78 in Fig. 5. This limit also is expressed as a percentage of from 0 to 9.99% above the desired feed rate R.
Still referring to Fig. 1, digital switch 80 is an operator activated switch to input into the memory, the desired minimum or low level of the material in the container 12. The range of this switch is from 0 to 99.9~. Thus, for example, if the operator desires the system to shift into its refill mode when the container 12 is down to 5% of its capacity, he sets the low level switch 80 at 05.0~. Digital input switch 82 is an out of low level switch with a range of from 0 to 99.9~ so .~
that the operator can input into memory the desired level for the system to shift out of its refill mode to its normal operative mode. Thus, for example, the operator could set this switch for 90.0%, whereby when the container 12 reaches 90% of its capacity, the system would shift out of its refill mode to its normal operative mode.
In addition, the processor also receives a signal from a shaft encoder 83. This allows a correlation to be made between the shaft angle and the system noises induced by the movement of the machinery mounted on the scale or movement of the product in the storage hopper. This correlation may then be used as a correction factorr subtracting out noise , .

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components due to moving machinery on the scale such as for example, the motor, gear box, augers, as well as movement of the material in the container. The processor 56 is provided with a learn mode input switch 85, which is shiftable between normal S operation and learn mode operation. When a new material is going to be processed by the system or when the system is first install~d, the system is set in operation, but instead of dis-charging the substance 14 out of the system, it is collected in a small container, not shown, and retained on the scale 22 so that there is no net loss of weight from the scale. The switch 85 is shifted to its learn mode position. The motor 18 is run throughout its speed range and the shaft encoder 83 senses the shaft angle, at the various speeds of rotation, while the input circuit through the LVDT 24 picks up the noise corresponding to the rotational position of the drive shaft and sends out digital signals to the processor, which are stored in memory. After this information has been stored in memory, the small container is removed from the scale and the switch 85 is shifted to its normal operation. Fig. 6 illustrates the positional relation-ship of the shaft encoder 83 with respect to the induced systemnoise for a particular speed during the learn mode of operation.
Fig. 7 illustrates the output of the ADC 52 with respect to time, before it is corrected for the induced system noises.
Processor 56, as another operation thereof, subtracts the ; 25 system noise stored data from the data received from the ADC 52 ; to present connected values of this information for processing.
Fig. 8 illustrates the corrected output from the ADC 52 for one time cycle of operation. Any suitable type of shaft encoder may be employed such as a Series 2500, Optical Encoder, as ., manufactured by Renco Corporation.

` The microprocessor 56 has, as an output, a display :

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device 84 which indicates the total feed commanded. This device indicates the total feed asked for by the operators over a relatively long period of time. Thus, the processor, as one operation thereof, receives the selected feed rate R from the input switch 68 and integrates it with respect to the elapsed time and continuously displays the total feed commanded, in pounds. As another output there is provided a display device 86 which indicates the actual total feed dis-charged from the feeder assembly 10. Thus, the processor, as one operation thereof, receives a signal from the ADC 40 corre-sponding to the total scale weight, which indicates the quantity of material remaining in the container. This signal represents the amount of weight of material in the feeder 12.
Any change in this signal, except during refill, represents the amount of material fed. These changes are totalled by the processor to give the actual total feed, in pounds. During refill the amount of material fed is computed by the processor from the reading of the feed rate meter and the time it takes to refill. When refill is completed the signal from the ADC -40 is again used to compute the total amount of material fed.
The operators can compare the actual total feed, as displayed at 86, with the total feed commanded, as displayed at 84, to determine how the system is functioning and, if necessary, take corrective action.
; 25 A feed rate display device, such as a four digit meter, 88, for example, shows the actual feed rate in pounds per hour of the feeder assembly. Thus, the processor, as another operation thereof, receives the amplified scale weight signal from the ADC 52 and corrects this signal as pointed out hereinbefore, and then differentiates the signal with respect to time to produce a signal indicative of the present rate of ; - 17 -, feed. This can be visually compared to the desired feed rate as set by the input switch 68 to determine possible malfunctions in the system.
A scale weight display device, such as a three digit meter 90, for example, is provided to indicate the actual percentage of product remaining in the container 12 on the scale 22. Thus, the processor, as still another operation thereof, receives a signal from the ADC 40 corresponding to the weight on the scale 22 and computes the actual percentage of material remaining in the container 12. Next, there is provided, as another output of the processor 56, a three digit motor speed meter 92 which indicates the actual speed of the motor 18. That is, the processor receives a signal from a tachometer 93, indicating the speed of the motor 18, by a lS conductor 95 through a conventional analog-digital-converter 97, ... .
and outputs a motor speed on meter 92. While this speed is ; usually relatively constant, it may vary to some extent over a long period of time. It is advantageous for the operator to know, as any sudden variations may indicate a blockage of material in the system.
In addition, there are provided operational and warning indicators, such as lights, buzzers, or the like, for example, for purposes of keeping the operators informed. An underweight light 94 indicates when the actual feed rate, as indicated by the meter 88, falls below the underweight set point 72, and an overweight light 96 indicates when the actual feed rate exceeds the overweight set point 76. That is, when the actual feed rate falls below the line 74, Fig. 5, which is set by the underweight set point switch 72, the underweight : - :

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light 94 is actuated, and when the actual feed rate is above the line 78, Fig. 5, which is set by the overweight set point switch 76, the overweight light ~6 is actuated. Preferably there is a preselected time delay period of from about O to abou 3 minutes delay after the feed rate meter 88 indicates an overweight or an underweight condition before the warning lights are actuated. Light 98 shows when the system is in its refill mode, i.e. when the container 12 is being refilled. The light 100 indicates that the system is in its ACRILOK mode. This mode of operation will be explained more fully hereinafter.
Run light 102 indicates that the system is in operation and standby light 104 indicates that the system power has been applied, but all machinery is stopped. The light 106 indicates that the bin 12 is in its low level condition.

A control output 108 from the processor 56 is R ;~L ~e ;~ cd applied to a digital-analog converter (DAC) 110~ Any suitable type of DAC may be employed, such as a 10 bit Model AD7520L, as manufactured by Analog Devices, Inc., for example. In the DAC, !~
the digital pulses are converted to an analog signal, which is ¦-'':' ~ ~
applied to the tachometer 93 and an SCR motor control 112~.
Any suitable type of motor control may be employed such as Acrison, Inc.'s Model ACRlOOBTG, for example. This controller produces an output which is applied to the motor 18 to control the speed thereof, and thereby control the discharge rate of the material from the feeder assembly 10.
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In operation, the operator must determine whether he wishes to operate in the volumetric mode or the gravimetric mode. If the volumetric mode is selected, then the operator sets the motor speed switch 67 to the desired motor speed. In '',' . .' ,.

Q6~8 this mode of operation, the output of the processor is a digital word conveyed by conductor 108 to the DAC 110. The DAC causes a vo}tage from 0 ~o 6 volts to appear on conductor 111 and the SCR motor control adjusts the speed of the DC motor 18 until the output of the tachometer 93 exactly equals the voltage on the conductor 111. While this mode of operation is desirable at certain times, it does not provide as high a degree of accuracy as the gravimetric mode and, consequently, the gravi-metric mode is predominantly employed.
In operation, when the operator sets the swtich 62 to the gravimetric mode of operation, the operator then sets the feed rate switch 68 to the desired feed rate R (LBS./HR), which, as discussed hereinbefore, determines the slope of the feed curve or line 70, Fig. 5. The processor then computes the conversion time which may be, for example, T = S (2.5) in seconds, where S is the scale weight as set by switch 66, R
is the desired feed rate set by switch 68, and 2.5 is a constant which, when combined with S/R, produces the conversion time in seconds. The conversion time is the time for each cycle of ; 2~ operation as shown in Figs. 3 and 4, during which many samples of the input signals are taken and one calculation of feed rate is made. Next, the ramp offset 50 is energized which, as pointed out hereinbefore, limits the range of the output 54 of the amplifier 44 to between ~5 volts and -5 volts. Initially, it sets said output at about t5 volts. Next, the processor starts the conversion time. The conversion time T, may, for example, be about 250 milliseconds. A plurality of samples are taken based on the input from the ADC 52, which may for example, be about 100 during each conversion time. The conversion time, T, or time to complete one cycle of operation, is selected to be within the range of from about 1/4 seconds ., , . , ,,. . -- ' '' ~ ' '' :

111(16~8 minimum to a maximum of from about 100 to 200 seconds. During this cycle, the output from the amplifier 44 moves from about ~5 volts to about -5 volts. Each sample is stored in memory. The samples, generally illustrated.in Fig. 5 by dots, form thé actual feed curve 114. One of the most important ''','' .

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''' -' ~1~8 operations of the processor is to compute a regression analysis on these samples with respect to time T, and thence compute the RMS error on T.

Fig. 5 illustrates an upper 3 RMS error line at 121 and a lower 3 RMS error line at 123. If less than 20, for example, sample data points exceed 3RMS error in either direction, as indicated at 115 in Fig. 5, regression on T is recomputed with the data points exceeding 3 RMS, as indicated at 117, excluded. Thence, the computed slope of the actual feed curve is compared with the slope of the desired or set point feed line, and a corresponding correction command is ¦
outputted at 108 to adjust the motor control 112, thereby to ¦
adjust the actual rate of discharge of the material from the feeder assembly 10. This time cycle of operation is continuously repeated to continuously adjust the motor control 112., I~ more than 20, for example, sample data points exceed 3 RMS error in either direction, as indicated at 119 in Fig. 5, the system is changed into its ACRILOK mode.
That is, the ACRILOK light 100 is energized and the output command 108 to the DAC 110 and motor control 112 is not updated, but continues in its present state. That is, the processor continues to receive sample signals from the ADC
52 and compute the regression analysis thereof, but no correction command is outputted at 108. The feed rate meter 88 is also locked at the last control data point. The feed system remains in a locked condition until in a subsequent time cycle of operation less than 20 data points exceed 3 RMS

e or, and then the system is returned to its normal operatlng .,., , '.
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~ 6~-8 mode and the correction command is again outputted at 108.

As still another operation of the processor, the total feed commanded, as indicated at 84, is compared to the actual total feed, as indicated at 86, periodically, such as every 5 or 10 minutes, for example. If there is a deviation exceeding predetermined limits, the processor modifies the aforementioned command output at 108 to gradually correct the actual feed to the total feed. This is programmed to take from about 5 minutes to about 10 minutes, thereby to avoid sharp fluctuations in the feed rate command, but nevertheless, obtain as close as possible the total feed selected over a long period of time.

A further operation of the processor, is to determine when the scale weight, as indicated by the meter 90, drops to a predetermined low level, as set by the low level switch 80, and then search for an "on rate" condition. That is, the output signal outputted at 88 is monitored until the difference between it and the feed rate switch 68 is less than a predetermined error limit. Thence, the system is changed into its refill mode wherein the output command 108 and feed rate meter 88 are not updated, but are retained in its present state, similar to its operation as described hereinbefore in connection with the ACRILOK mode. At the same time, a command is outputte~
to a refill circuit 120, which sends a signal to a refill controller 122 that controls the flow of material from a ~efill source 124 to the container 12. The controller 122 could be an ¦ AC motor when handling dry particulate material or could be a valve when handling liquids.

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~ 8 The system remains in thc refill mode until the processor detects that the container 12 is refilled, as indicated by the scale weight meter 90, an~ as selected by the -out of low level switch 82. At this time, the p~ocessor outputs a signal to the refill circuit 1~0 which, in turn, r direct! the refill controller 122 to di~continue refilling the container 12. The processor then returns the syste~, to its normal operational mode.
, .
Figs. 9 to 14 are various flow charts of the computer 56. Thus, Fig. 9 is a flow chart showing the wait subroutine, and Fig. 10 is a flow chart of the second interrupt t subroutine, which is a display type subroutine. Fig. 11 i6 a flow chart of the derive subroutine wherein the normal conversion time is calculated. Figs. 12A, 12B and 12C combine to form a flow chart of the main routine of the computer 56. Figs.
; 13 an~ l4 are flow charts of the calculate and learn mode subroùtines, respectively.

j Initial conditions and assumptions are, as follows:
- GRAV/VOL. = GRAV. I -ON/OFF = OFF
;~. AUTO/~N./BY-PASS= AUTO
SCALE WEIGHT = 1000. lbs.
FEED RATE SET POINT = 200 LBS./HR.
INTO LOW LEVEL = 20~
OUT OF LOW LEVEL = 80%
MOTOR SPEED = 50%
ASSUME MAX. FEED RATE OF MACHINE = 2000 LBS./HR
REAL TIME CLOCK RATE = 1 KHZ (Clock causes interrupt) ,. . .
,'` . . .

'' ,' .

~ llQ6~8 ¦ Flags set by hardware:
¦ Grav. Flag ¦ Run Flag ¦ Learn Flag I ~By-Pass Flag~
¦ ~an. Flag 5 ¦ Reset total Flag Number of Samples per slope calcu~ation = 256 ~ ¦ The t;me between samples is chosen so that you have covered .~ ¦ about 60% of the range of the ramp offset 50 for each slope ¦ calculation. The ramp offset is reset for each new slope calculation. Thus, the lower the set point the longer it ' takes to calculate the slope.
`~; .
The following is a program with descriptive co~neA~s for carrying out the basic operations of the computer 56: ' . , . . -1 ~-',,, :~ . . . ~.' ~ ' ~ ' .
. .
~ ' ' . ' .
.
: ' ' ' , ~ ' . ' . . .

. ' . , .

Il-`` 11106~)8 :~ *L T/2 *T T/2 . , .
END ?
::
177554 OUT = 177554 ) 177552 DATA = 177552 ) :`
177554 OFFSET = 177554 ) 177550 SET = 177550 ) 177550 LKS = 177550 ) 040200 ) i~
04,~400 TWOF = 040400 ) 0407~0 SIXF = 040700 ) ~, 000004 WAITR = 4 . ) 000011 READ = 11 ) DEFINITIONS OF.
000012 WRITE = 12 ) CONSTANTS, ADDRESSES i:
000000 R0=%0 ) AND REGISTERS.
000001 Rl = %l ) 0000~2 R2 =%2 ) ¦ :
000003 R3 =%3 ) ¦ -000004 R4 =%4 ) 00O005 R5 =%5 ) 000006 R6 =%6 ) 000006 SP =%6 000007 PC =%7 ) '~ . .
:. 11 . I
` . ' ., :~ . l .,' ~: . ," ' . ~

:' .:
.. . . .

~` lllQ6~8 057452 $ADR=57452 ) .: 060206 $CMR=60206 ) 063500 $DVR=6350~ ) 061664 $GCO=61664 ) .064146 $IR=64146 ) LINKS TO FLOATING POINT
. 064232 $MLI=64232 ) MATH PACKAGE (FPMP-WRITTEN
064412 $MLR=64412 ) BY D.E.C.) . . 064772 $NGR-64772 ) ; 065146 $POLSH=65146 3 060264 $RC1=60264 ) 065024 $R1=65024 ) 057446 $SBR=57446 ) . 000174 .=174 000174 05~72~ .WORD INT ) SET UP lKH%. CLOCK INTERRllP' ~:
000176 000340 .WORD 000340 ) VECTOR .
.~ ' 050000 =50000 . .05~00001~767 START: MOV PC, STKST ) . 003642 ) .
.. ; 050004 016706 MOV STKST, SP ) -; STACK POINTER I S
`: 003636 ~ NOW POINTING
050010 .00574Ç TST (SP) - ) TO STKST
: 050012 013700 ~IOV C~ #177552,R~
`: 177552 050016 052767 BIS ~2, SET ) jINIl'IALIZE
000002 ) OF~SET
127524 ) VOLT~.~.E TO
.~. 050024 ~12767 MOV ~177777,0FFSET ) ZERO (IN
) COMPLEMENT
! ) FORM .
'`:

~ 6~8 ~
177777 ) 127522 . ); INITIALIZE
050032 005~67 CLR SET ) CONTROL
127512 ) VOLTAGE TO
RQ ~ GE OOl ? ZERO(IN
05 ~ 36 012767 MOV # 177777, OFFSET ~ COMPLEMENT
) FORM) . 177777 127510 ) INITIALIZE
050044 000004 IOT )TELETYPE
050046 00000~ .WORD 0 )THROUGH
050050 002 .BYTE 2,0 ~IOX (IO~: IS
; )WRITTEN BY
)D.E.C.) 050051 ~00 ; 050052 0~0~04 IOT )SETS UP
' )CONTROL P
050054 05O060 , WORD ASK )RETURN
)ADDRESS, 050056 003 .BYTE 3,0 ) . ~50057 00~ ~ :
: 050060 012701 ASK: MOV #TABLEl, Rl; GET ADDRESS OF
~ TABLE OF
QUESTIONS
05040~ ' ; 050064 012767 MOV #9., LOOP; SET UP LOOP FORNINE QUESTIONS
: ~ . ~ 000011 , : 003552 050072 012700 MOV #MTABTE,R0;GET ADDRESS OE
TABLE CONTAINING
,i~ POINTERS TO THE 9 QUESTIONS

;, ' . I
'': ' . . ' . .
!
.. . .. .. .... . .. ~ .

6~8 .
:.

050076 012067 MORE: MOV (R0)+,WBUFFER
~00002 ) PRINT THE
~5~104 000000 WBUFFER: .WORD 0 ) QUESTION
- 050106 012 .BYTE WRITE, 1 ~50107 001 ) GET A REPLY
050112 050250 .WORD BUFFER ) ~ -050114 011 .BYTE READ,0 050115 ~00 050116 00004 WAITT: IOT ) WAIT UNTIL
) REPLY IS
050120 050116 .WORD WAITT ) GIVEN BY
) OPERATOR AT
050122 004 .BYTE WAITR,0 ) TTY.
... .
050123 ~00 050124 012746 MOV #BUFFER~6,(SP)-; PUT ADDRESS
; OF REPLY ON
STACK

~ 050130 016746 MOV BUFFER ~4,(SP)-; PUT LENGTH
i OF REPLY ON
ii STACK

050134 162716 SUB #2, (SP) 0~0002 050140 005046 CLR (SP)- ) )FREE FORMAT CONVERSION
; 050142 005046 CLR (SP)- ) 050144 004767 JSR PC,$RCI; CONVERT REPLY
- TO FLOATING POINT 1.

050150 012621 MOV (SP)+,(Rl)+) - ) STORE REPLY IN
050152 012621 MOV (SP)+,(Rl)+) TABLE 1.
'' .

~ .

6~8 ~50154 ~05367 DEC LOOP
0~3464 0501~0 001346 BNE MORE
050162 005046 CLR (SP)-050164 012746 MOV #042722,(SP)- ) PUT FLTING
PT. 168p ON

RQ@GE 002 050170 012701 MOV #TABLE 1~14,Rl 05~414 ~50174 014146 MOV (Rl)-, (SP)- ) 05~176 014146 MOV (Rl)-, (SP)- ) CALCULATE
) #SAMPLES/SEC.
05020~ 014146 MOV (Rl)-, (SP)- ) 050202 014146 MOV (Rl)-, (SP)- ) 050204 004467 JSR R4, $PoLSH

050210 063500 $DVR
050212 050214 .WORD .~2 050214 011667 MOV (SP), HOLD8 )STORE #SAMPLES/
~0345~ ) SEC
050220 016667 MOV 2(SP), HOLD9 ) 0000~2 050226 004467 JSR R4, $PoLSH
)DIVIDE SAMPLES/
014714 - )SEC BY 16BO TO
)GIVE THE # OF
050232 063500 $DVR )INTERRUPTS PER
)SAMPLE
050234 065024 $RI
050236 050240 .WORD .~2 050240 012667 MOV (SP)+,INTSAM; STORE RESULT.

050244 000167 JMP INIT; GO TO THE INITIALIZATION
SECTION

050250 000100 BUFFER: 100 . - 29 -' .`' ' ' Q6~8 0502520000~0 ~ ) BUFFER FOR
) REPLYS TO
050254000000 0 ) QUESTIONS
050356 .-.~10~
05035605045~ MTABLE: TABLE 3 ~5~36~050472 TABLE2 3 050~64~50522 TABLE4 )POINTERS TO
05036605~544 TABLE5 3THE QUESTIONS

05037405~630 TABLE8 050450 TABLEl: .=.+50 0504500~0~14 TABLE: TABLE2-TABLE-6 05~45200000~ 0 050456015 .BYTE 15,12 050460106 .ASCII 'FEED V/S''; VOLTS/SECOND
FEED RATE

05~464040 05~465126.
050466~57 RQ@GE 003 05~470075 050472 .EVEN
050472000006 TABLE2: TABLE3-TABLE2-6 050474~000~ 0 . .
. - 30 -lQ608 ~50476000~06 TABLE3-TABLE2-6 050500124 .ASCII 'TIME-'; SMALL SAMPLE TIME
IN SECONDS
0505~1111 0505~3105 050506 .EVEN
050506000006 TABLE3: TABLE4-TABLE3-6 05~510~000~ ~

050514043 .ASCII '#SAM='; #SAMPLES PER
SMALL SAMPLE TIME

050522 .EVEN
050522000014 TABLE4: TABLE5-TABLE4-6 05~5240000~0 0 050530105 .ASCII 'ERR BND V/S='; SMALL
SAMPLE ERROR
BAND IN
VOLT/SECOND
~50531122 05~534102 . .

'' ,.'.' . . .

6~8 ~5~541057 ~50543075 ~50544 .EVEN
050544000016 T~BLE5: TABLE6-TABLE5-6 050546~0~00 0 050552043 .ASCII '#SM SAM/LARGE='; # OF SMALL
SAMPLES
PER LARGE
SAMPLE
TIME.

05~555040 05~556123 0505571~1 RQ@GE 0~4 050567~75 050570 .EVEN
050570 000006 TABLE6: TABLE7-TABLE6-6 ~-~5~572 0~000~ 0 ~50576 105 .ASCII 'ERR K='; OUTPUT ERROR
CONSTANT "K"
THIS IS SYSTEM
GAIN.

. .

` . - 32 -., .~ .

~ll()GQ8 05060~122 ~50603075 050604 .EVEN
050604000016 TABLE7: TABLE8-TABLE7-6 0506~6000000 0 050612043 .ASCII '#SM SAM B4 SW='; # OF SMALL
SAMPLES
BEFORE
050613123 SWITCHING.

050617~01 050621~40 ~5~623064 05~625123 ~5~626127 05~627~75 050630 .EVEN
05063000~024 TABLE8: TABLE9-TABLE8-6 050632000~00 0 050636123 .ASCII 'STARTVP ERR BND V/S=' 05~640101 . ~
` - 33 -, .

6~8 ~50651 040 05~652 102 RQ@GE005 05~654 1~4 05~655 ~4 p50656 126 p50657 ~57 p5~66p 123 p5p661 p75.
p5p662 . .EVEN
p5p662 pppp24 TABLE9: TABLEZ-TABLE9-6 ~5p664 ~pp~p 050670 043 .ASCII '#SM SAM IN STARTUP=' 05~671 123 05.0673 04 05~674 123 05~675 101 05~676 115 05070~ 111 050702 04~

-` 111(~6~8 ~507~7 . 124 ~50710 125 ~50711 120 ~50712 075 050714 .EVEN
050714 000 TABLEZ: .BYTE 0 : 050716 .EVEN
050716 00~167 LINK: JMP RESET

050722005737 INT: TST @#177552; START OF INTERRUPT
SERVICE.

050726005367 . DEC INTS
)IS IT TIME TO
002556 ~ SAMPLE~

050734000002 RTl 050736004767 SAMPLE: JSR PC, SAVE

:- 050742005267 INC SET; START A/D CONVERSION

..050746 105767 CK: TSTB SET
. 126576 ~!' 050752 100375 BPL CK
; 050754 016700 MOV DATA, R0; GET THE A/D OUTPUT

. RQ@GE 006 050762016767 MOV INTSA, INTS; RESET #
INTERRUPTS/
SAMPLE.

:

6~8 ~02520 050770 022700 CMP #980.,R0 )IS THE A/D OUT-. ) PUT GREATER THAN
001724 )9 VOLTS? IF
)YES RESET.

050776 060067 ADD R0,Y~2 )SUM THE Y VALUE
002514 )FOR THE
)REGRESSION.

~02506 051006 016701 MOV X, Rl )MULTIPLY THE X
002506 )BY THE Y
051012 004767 JSR PC,MULTY
001~62 051016 06016i ADD Rl,XY~2 )SUM THE XY VALUE
05l022 005567 ADC XY )FOR THE
)REGRESSION.
0~2506 051026 060067 ADD R0,XY
~02502 051032 005367 DEC X; REDUCE X VALUE BY 1 051036 001402 BEQ CALC; IF X=O IT IS TIME TO
CALCULATE THE SLOPE
051040 004767 JSR PC,RESTORE
~01312 051044 016767 CALC: MOV N,X; RESET THE X VALUE
0~2500 051052 016767 MOV Y,YC
002436 ) STORE THE
0~2464 051060 016767 MOV Y~2,YC~2 i.~8 :, ~2432 ~246 051066 016767 MOV XY,XYC

- )STORE THE ~X

051074 016767 MOV XY~2,XYC~2 0511~2 005~67 CLR XY
~02426 ~51106 005~67 CLR XY~2 )RESET ~XY AND
)~Y FOR NEXm 002424 )SAMPLE PERIOD.

051116 005067 CLR Y~2 051122 016746 MOV Nl+2,(SP)- I
002426 )PUT # SAMPLES
)ON THE STACK.
RQ@GE 0~7 051126 016746 MOV Nl,(SP)-0~242~
051132 01670~ MOV XYC, R0 0~24~2 ; 051136 016701 MOV XYC~2,Rl - ~02400 )CONVERT ~XY TO
)A FLOATING POINT
051142 004767 JSR PC,DFLOAT )# AND PUT IT ON
` )THE STACK.

:; 051146 004467 JSR R4,$POLSH
, 013774 051152 064412 $MLR ) (#SAMPLES) x ' ) ~XY
~51154 051156 .WORD .+2 ., .

` . - 37 -'.'' ' :
.

``- 111~608 ~51~56 016746 MOV Xl+2,(SP)- ) )PUT ~X ON
0~2350 )STACK
051162 016746 MOY Xl,(SP)- ) 051166 016700 MOV YC, R0 0~2352 )CONVERT ~Y TO
051172 016701 MOV YC~2,Rl )FLOATING POINT
)AND PUT IT ON
002350 )THE STACK.
051176 004767 JSR PC,DFLOAT

051202 004467 JSR R4,$PoLSH
01374~ )GET (#SAMPLES~
) (~XY)-~X~Y
051206 064412 $MLR
051210 057446 $SBR
051212 051214 .WORD .+2 ~51214 016746 MOV Nl+2,(SP)-)PUT ~ SAMPLES
002334 )ON THE STACK.
051220 016746 MOV Nl,(SP)-` 002326 051224 016746 ~OV X2~2,(SP)-)PUT ~X ON
002276 )STACK.
051230 016746 MOV X2,(SP)-~2270 051234 004467 JSR R4,$POLSH
)GET (#SAMPLES) 013706 )(~x2) 051240 064412 $MLR
051242 051244 .WORD .~2 051244 016746 MOV X1~2,(SP)-0~2262 )PUT ~X ON
)STACK
051250 016746 MOV Xl,(SP)-, . .
~ - 38 -:
~^ 111~6~8 :
~02254 051254 016746 MOV X1~2,(SP)- ; X ON STACK AGAIN

051260 016746 MOV Xl,(SP)-002244 _ 051264 004467 JSR R4,$PoLSH ¦
; 013656 051270 064412 $MLR
)(#SAMPLES) RQ@GE 010 ) (XY)-(X)(Y)-)(#SAMPLES) 051272 057446 $SBR )(~X2)-(X)(Y) ) 051274 063500 $DVR ~ SLOPE
:. ) 051276 064772 $NGR
051300 051302 .WORD .+2 051302 016746 MOV SAMS01+2,(SP)-) )PUT # SAMPLES/
002252 )SECOND ON
)STACK
051306 016746 MOV SAMS01,(SP)-` 002244 051312 004467 JSR R4,$PoLSH

051316- 064412- $MLR
051320 051322 .WORD .~2 051322 005046 CLR (SP)-':' ; 051324 012746 MOV #041710,(SP)-;FLOATING POINT
i`~; 04171~
051330 004467 JSR R4,$POLSH

~` 051334 063500 $DVR ; VOLT - SLOPExSAMPLE x ~ SEC SEC lOO
i ~51336 051340 .WORD .+2 ~`; 051340 011667 MOV (SP),TEMP )STORE V/S FOR
002216 )LATER USE.
051344 016667 MOV 2(SP),TEMP+2 :' .

, - 39 -. .
.,~', .
.; , . . .

6~ 8 000~
0~2212 051352 016746 MOV PREV+2,(SP)- ) )PUT PREVIOUS
002212 )V/S ON STACK
051356 016746 MOV PREV,(SP)-~51362 004467 JSR R4,$POLSH
013560 )PREV-CURRENT
)v/s ~
051366 057446 $SBR
~51370 051372 .WORD .+2 051372 032716 BIT #100000,(SP) 051376 001404 BEQ OVR )GET THE
)~BSOLUTE VALUE
051400 ~04467 JSR R4, $POLSH )¦PREV V/S-) CURRENT V/SI

051404 064772 $NGR
051406 051410 .WORD .+2 )LARGE OR SM~LL
002156 )ERROR BAND?

; 051416 005367 DEC ERRSW-SM~LL--DECREASE # SMALL
SAMPLES BEFORE
; SWITCHING ERROR
BANDS.
~02150 ; 051422 001405 BEQ LARGE
051424 016746 MOV SE~2,(SP)-)MOVE SMALL
-~ 002150 )ERROR BAND
)ONTO STACK.
051430 016746 MOV SE,(SP)- ) 051434 000404 BR TSTE; TEST FOR ACRILOK
RQ@GE 011 . .
.

6~8 ~51436 ~16746 LARGE: MOV LE+2,(SP)- ) )MOVE LARGE
~2142 )ERROR BAND
)ONTO STACK. -051442 ~16746 MOV LE,(SP)-051446 004467 TSTE: JSR R4,$PoLSH
~13474 ) COMPARE
)¦PREV V/S-p51452 ~60206 $CMR ) CURRENT v/sl ) TO ALLOWABLE
051454 051456 .WORD .+2 ) ERROR IN V/S
) AND JMP IF TOO
051456 ~03402 BLE .+6 ) LARGE.
; 051460 000167 JMP ACRILOCK
00063~
051464 016767 MOV TEMP,PREV; )THIS IS .+6 0~2072 )YOU ARE WITHIN
; )THE ERROR BAND
002074 )(STORE THE FEED
)RATE IN V/S) 051472 016767 MOV TEMP+2,PREV12) 0~2070 051500 005267 INC UPDAT;SET THE FLAG TO INDICATE
A NEW FEED RATE HAS JUST
` BEEN CALCULATED
,.............................. .
' 002002 ~` )ARE WE USING
002102 )LARGE OR SMALL
'~ )SAMPLES?

~a~ 051512 005367 DEC LOS:DECREMENT # OF SM~LL SAMPLES
~2074 , 051516 016746 UPDATE: MOV K+2,(SP)-- )PUT OUTPUT
002076 )CONSTANT
;~ )(SYSTEM GAIN) 051522 016746 MOV K, (SP)- ~ON THE STACK.
~02070 051526 016746 MOV FR 12~(SP) )PUT DESIRED
002072 )FEED RATE ON
051532 ~16746 MOV FR,(SP)- ) ` - 41 -.: , . . .

' ' , : , . :-' : -)6~8 ~02064 051536 016746 MOV PREV~2,(SP)- ) )PUT CURRENT
002026 )FEED RATE ON
)THE STACK.
051542 016746 MOV PREV,(SP)-0~2020 051546 004467 JSR R4,$PoLSH
~13374 - ) 051552 057446 $SBR )(CURRENT-DESIRED) )K ~ CONWOR
051554 064412 $SMLR )PREVIOUS MOTOR
)SPEED.
051556 065~24 $RI
051560 051562 .WORD .+2 051562 062667 ADD (SP)~,CO~WOR ) 051566 026727 CMP CONWOR,#2000 )IF RESULT IS
0020~0 )GREATER THAN
` )2000 ~6V@
051574 100403 BMI CNTU )OUTPUT OF D/A) i )MAKE IT=2000;
051576 012767 MOV#1777,CONWOR )I.E., LIMIT
)RESULT TO 6 VOLTS
~01777 RQ@GE 012 051604 042767 CNTU:BIC#02,SET; GET SET TO UPDATE MOTOR
~ SPEED.
.',. i ` 000002 - )THE D/A USES
002010 )NEGATIVE LOGIC.
~51616 016767 MOV CONWOR,OUT

051624 005167 COM CONWOR; BUT THE PROGR~MMER
PREFERS TO THINX
; POSITIVE.

- 42 -.

. . . .
.

lQ6Q8 .

~01776 051630 004767 JSR PC,RESTORE;GO BACR TO WHERE
YOU WERE BEFORE
BEING RUDELY
INTERRUPTED.

051634 016746 LAR: MOV PREV~2,(SP)- ) 0~173~ ) 051640 016746 MOV PREV,(SP)- )IF YOU ARE
)CALLING FOR
001722 )LARGE SAMPLES, )I.E. AN AVERAGE
051644 016746 MOV AVG~2, (SP)- )OF THE V/S
)CALCULATIONS, ~01762 )THEN YOU ARE
)HERE. COMPUTE
051650 016746 MOV AVG, (SP3- )THE RUNNING
)AVERAGE.
; ~1754 .. ) 051654 004467 JSR R4,$POLSH

051660 057452 $ADR
051662 ~51664 .WORD .+2 ~01744 , )IF YOU HAVE
051670 001411 BEQ CALL )ENOUGH V/S
)CALCULATIONS
~ 051672 005367 DEC SSLST )USE THE
- )AVER~G~;I.E.
001736 )JUMP TO CALL.

0S17~0 012667 MOV (SP)+,AVG.
, ) 0~1724 )YOU DON'T HAVE
)ENOUGH V/S
051704 012667 MOV (SP)+,AVG~2 )CALCULATIONS.
` )RETURN TO WHERE
001722 )YOU WERE BEFORE
)THE INTERRUPT.
` 051710 004767 JSR PC,RESTORE

~00442 ` 051714 016767 CALL: MOV SSLSTI,SSLST ) ' .
.

.

6~8 001712 )RESET #SMALL
` )SAMPLES PER
051722 016746 MOV SSLSTRf2,(SP)- )LARGE SAMPLE
)TIME.

051726 016746 MOV SSLSTR,(SP)-;PUT #SMALL
SAMPLES/LAR6E SAM.
ON STACK.
0017~6 051732 004467 JSR R4,$POLSH
013210 )GET THE AVER.
)OF THE SMALL
051736 063500 $DVR )SAMPLES COM-)PRISING THE
051740 051742 .WORD .~2 )LARGE SAMPLE.
051742 012667 MOV (SP)+,PREV
001620 )STORE THE
; )AVERAGE.
- 051746 012667 MOV (SP)~,PREV~2 RQ@GE 013 051752 005067 CLR AVG ) ¦~
001652 )RESET THE AVG.
051756 005067 CLR AVG+2 ) ¦
00165~ 1 .:
051762 ~0~167 JMP UPDATE;REFRESH THE MOTOR
SPEED.
17753~
~51766 ~12667 DFLOAT: MOV (SP)~,RTRN
000104 `
051772 005046 CLR (SP)- ) 051774 005046 CLR -(SP) 051776 ~05700 TST R0 052004 005701 TST Rl 52006~ 00l432 - BEQ ZER27 :

:' .
' ': . -6~8 .

052010 00~403 - BR POS27 052012 005401 OVE27: NEG Rl 052016 005601 SBC Rl 052020 006l46 POS27: ROL -(SP~ ) 052024 012702 MOV #240,R2 ~00240 052030 006101 NOM 27: ROL Rl 052034 103402 BCS NOD27 )DOUBLE
052036 005302 DEC R2 )PRECISION
052040 000773 BR NOM27 )INTEGER TO
052042 000301 NOD27: SWAB Rl )FLOATING POINT
052044 110166 MOVB Rl,4(SP) )SUBROUTINE

052050 110066 MOVB R0,5(SP) ; 000005 052056 150200 BISB R2,R0 ~ 052060 000300 SWAB R0 052062 006026 ROR (SP)+

: ) ` 052066 006066 ROR 2(SP)`

052072 010016 MOV R0,@SP
052074 000137 ZER27: JMP @(PC)~ ) 052076 000000 RTRN: 0 052100 005002 MULTY: CLR R2 )INTEGER MULTIPLY
052102 005004 CLR R4 )SUBROUTINE
052104 012703 MOV #16.,R3 )16BIT X 16BIT=
000020 )32 BIT RESULT.
... .
: - 45 - .
,.~

6~8 ~52110 006200 ASR R0 ~52112 103001 MR: BCC .~4 052114 060102 ADD Rl,R2 ) RQ@GE 014 ) 052116 006002 ROR R2 )INTEGER
) 052120 006000 ROR R0 )MULTIPLY
052122 005303 DEC R3 )SUBROUTINE
052124 001372 BNE MR )16BITx16BIT=
052126 010001 MOV R0,Rl )32BIT RESULT.

052130 010200 MOV R2,R0 )(CONT'D.) 052134 052767 RESET:BIS#2,SET
)WHEN A/D OUTPUT -)RAMPS GREATER

)THAN 9V LIMIT
; 052142 062767 ADD#17,0FFDAC
)RESET IT CLOSE
0~0017 ) : :
)TO ZERO BY

)CHANGING THE
052150 ~16767 MOV OFFDAC,OFFSET ) :~
. )OFFSET VALUE
00~132 )COMPARING

)LOOPING ! NOTE
052156 012767 MOV#24150,LOOPl;90MILLISEC
)THE RESPONSE

)TIME OF 9O
0~0124 )MILLISEC FOR
052164 005367 A:DEC LOOPl )LARGE STEPS, &

)WHEN YOU GET

)CLOSE TO ZERO, 052172 062767 RESETA:ADD#l,OFFDAC
)RESPONSE TIME
0~00~1 , ) )OF 5 MILLI-~00106 )SECONDS.
052200 016767 MOV OFFDA~,OFFSET
0~0102 : 125346 llQ6~8 052206 012767 MOV~4440,LOOPl; 5MILLISEC 3 ; 052214 005367 B:DEC LOOPl )GREATER THAN 9V

~ 05222~ 001375 BNE B )CLOSE TO ZERO
; ~52222 0p5267 INC SET )BY CHANGING THE
125322 ) OFFSET VALUE &
.. ~
- 052226 105767 WATHO:TSTB SET )COMPARING, . 125316 ) LOOPING.NOTE THE
p52232 100375 BPL WATHO )RESPONSE TIME
052234 026727 CMP DATA, #177631 3OF 90MILLISEC
. 125312 ) FOR LRG STEPS &
. ` 177631 ) WHEN YOU GET
.~ p52242 100001 BPL CONTIN )CLOSE TO ZERO, 052244 ~00752 BR RESETA )RESPONSE TIME
:,, ) ~52246 ~16767 CONTIN:MOV N,X 30F 5 MILLISEC-~`1 0~1276 ) ONDS.

-:, ~` 052254 016767 MOV INTSA,INTS; RESET # INTER-i` RUPTS/SAMPLE
~1232 ~1226 RQ@GE 015 ;~ ~52262 ~5~67 CLR Y 3 ~1226 3ZERo THE SUMS;
~52266 ~5~67 CLR Y+2 3THROW OUT THIS
~1224 3SAMPLE PERIOD
` 052272 005067 CLR XY )DUE TO THE
,~": ) 052276 005067 CLR XY+2 )SETTING.

. .
:',. .
. .

:.,.

` lllQ6~8 0~1234 052302 ~04767 JSR PC,RESTORE;RETURN TO PREVIOUS
TASK.
0~050 052306 0~0000 OFFDAC:~
05231~ 000000 LOOPl:0 052312 00000~ HPREMP:HALTjIF HOPPER IS EMPTY HALT.
052314 005267 ACRILOCK: INC ACRILK
001266 ) 052320 005267 INC UPDAT }SET ACRILOCK
001162 )FLAG.
052324 004767 JSR PC,RESTORE ) 052330 012667 SAVE: MOV (SP)~, SAV
~00~16 052334 010~46 MOV R0,(SP)- ) 052336 010146 MOV Rl,(SP)- }
052340 010246 MOV R2,(SP)- )SAVE SUBROUTINE
052342 010346 MOV R3,(SP)-~52344 010446 MOV R4,(SP)-~52346 plp546 MOV R5,(SP)-052350 ~00137 JMP @(PC)I ) ~52352 00000~ SAV: 0 }
052354 00000~ SAVl: 0 052356 0~5726 RESTORE: TST (SP)+
05236~ ~12605 MOV (SP)+,R5 052362 012604 MOV (SP)~,R4 }
052364 ~12603 MOV (SP)+,R3 )RESTORE
052366 0126~2 MOV (SP)I,R2 )SUBROUTINE.
~52370 ~126~1 MOV (SP)~,R1 . ~
. i ,- . :

111~6~8 ~52372 ~126~ MOV (SP)I,R~ )RESTORE
)SUBROUTINE
~52374 ~ 2 RTI
~52376 ~16746 INIT: MOV TABLEl+12,(SP)-;# SAMPLES
) YOU COME HERE
176~1~ ) AFTER ANSWERING
) QUESTIONS TO
~524~2 ~16746 MOV TABLEl~l~,(SP)- ESTABLISH A
NEW SET OF
176~2 OPERATING
PARAMETERS.
~524~6 ~4467 JSR R4,$POLSH
~12534 ~52412 ~65~24 $RI
, ~52414 d52416 .WORD .~2 052416 012667 MOV (SP)+,HOLD; INTEGER # SAMPLES.
~1226 d52422 dl6746 MOV TABLE1~12,(SP)-) ; 175764 RQ@GE 016 052426 016746 MOV TABLEl+10,(SP)-) 052432 016746- MOV TABLEl112,(SP)-) 175754 )CALCULATE NEW
052436 016746 MOV TABLEl+10,(SP)-) ~X =
175746 IX(x~
052442 005046 CLR (SP)-052444 012746 MOV #ONEF,(SP)-:.................................................... ) 04~200 05245~ 004467 JSR R4,$POLSH

d52454 d57452 SADR
052456 064412 $MLR
052460 ~52462 .WORD .~2 052462- 005046 CLR (SP)-.`.~ .
'`' .

6~8 ~52464 ~12746 MOV #TWOF,(SP)- ) ~404~
05247~ ~4467 JSR R4, $PoLSH
; 012452 ICALCULATE NEW
~52474 063500 $DVR ) ~X -d52476 d5250~ .WORD .+2 ) x (x+l) ~52~0~ 012667 MOV (SP)~,HOLDl 0~1146 )PUT IT IN
)STORAGE
~s25d4 dl2667 MOV (SP)+,HOLD2 05251~ 0d5~46 CLR (SP)-d52512 dl2746 MOV #ONEF,(SP)-d4d2dd ~52516 dl6746MOV TABLEl+12,(SP)-) 17567~ ) ) ~52522 ~16746MOV TABLEl+l~,(SP) ) ~52526 ~5~46 CLR (SP)- )CALCULATE NEW
d5253~ ~12746 MOV #TWOF,(SP)- ) EX
d4d4~ )(2X+l)(X+l)(x) ~52534 dd4467 JSR R4,$PoLSH
~124~6 d5254d ~64412 $MLR
52542 d5?452 $ADR
~52544 052546 .WORD .12 ~52546 ~16746MOV TABLE1~12,(SP)-) `.' l7564d 052552 ~16746MOV TAB~El+l~,(SP)-) :,. ) 052556~ 016746 -MOV TABLEl+~2,(SP)-) -`` 17563~
,',; .

;'.,~
.'' .

.

6~!8 ~52562016746 MOV TABLE1~10,(SP)-~52566~5046 CLR (SP~- ) 05257~~12746 MOV #ONEF,(SP)- ) 0402~ ) RQ@GE 017 0525740~4467 JSR R4,$PoLSH
~12346 ~526p~~57452 $ADR
0526~2~64412 $MLR
d526d4d64412 $MLR )CALCULATE NEW
~526d6~5261d .WORD .+2 ) ~X
d52610~d5d46 CLR (SP)- )(2x+1)(x~1)(x) d52612dl2746 MOV #SIXF,(SP)-d4d7dd d526160d4467 JSR R4,$PoLSH
dl2324 d52622~635dd $DVR ¦
~52624052626 .WORD .~2 052626012667 MOV (SP)~-,HOLD3 ) PUT IT IN
~01024 3 5TORAGE
052632~12667 MOV (SP)~,HOLD4 001~22 ~52636 ~16746 MOV TABLE1~42,(SP)-) 1756~ ) ~52642 ~16746 MOV TABLEl14p,(SP)-) )CONVERT NEW
175572 )# SMALL
~ )SAMPLES BEFORE
- 052646 004467 JSR R4, $PoLSH )SWITCHING ERROR
)BANDS & CONVERT
012274 )TO INTEGER
052652 065024 $RI
~52654 052656 .WORD .+2 i ?8 052656 012667 MOV (SP)+,HOLD5;PUT IT IN STORAGE

00 00~0~
052662 016746 MOV TABLEl+22,(SP)-) 052666 016746 MOV TABLE1~20,(SP)-)CONVERT NEW
)#SMALL
175526 )SAMPLES PER
)LARGE SAMPLE
052672 004467 JSR R4,$PoLSH )& CONVERT TO
)INTEGER.

052676 065024 $RI
052700 052702 .WORD .+2 052702 012667 MOV (SP)+,HOLD6; PUT IT IN
STORAGE
00~756 ~52706 016746 MOV TABLEl+32,(SP)-) 052712 016746 MOV TABLEl+30,(SP)-) )CONVERT NEW #
175512 )SM~LL SAMPLES
)BEFORE SWITCH-052716 004467 JSR R4,$POLSH )ING TO LARGE
)SAMPLES &
012224 )CONVERT TO
)INTEGER.
052722 065024 $RI
) ~ 052724 052726 .WORD .+2 ;.
052726 012667 MOV (SP)+,HOLD7; PUT IT IN
STORAGE
~ 000734 :~ 052732 005067 CLR LKS;TURN OFF THE REAL TIME
; CLOCK

; 000572 RQ@GE 020 )ZERO THE SUMS.
052742 00S067 CLR XY+2 , .' l.Ub~
.

~52746 0~5067 CLR Y
000542 )ZERO THE SUMS.
~52752 ~05067 CLR Y+2 00054~ ) 0~756 016767 MOV HOLD8,SAMS01 0~0572 052764 016767 MOV HOLD9,SAMS01~2 ) 052772 016767 MOV HOLD7,LOS

P53000 ~16767 MOV HOLD6,SSLST
,'`: - ) 00066~ ) 053006 016767 MOV HOLD5,ERRSW
00~650 . ., ~
00~556 053014 016767 MOV HOLD4,X2~2 )MOVE THE NEW
000640 )PARAMETERS INTO
)REAL TIME
000504 )VARIABLES
)DURING THE TIME
053022 016767 MOV HOLD3,X2 )WHEN THE CLOCK
)IS OFF SO THAT
000630 )THE TRANSITION
` )DOES NOT OCCUR
0p0474 )IN THE MIDDLE
`` )OF A SAMPLE
" 053030 016767 MOV HOLD2,Xl+2 )PERIOD.
00062p ~0~474 053036 016767 MOV HOLDl,Xl 0~610 .

: .

6~8 053044~16767 MOV HOLD,N
00~6~0 ~53052016767 MOV SSLST,SSLSTI

~00556 05306~~16767 MOV N,X
0~0464 053066~16767 . MOV TABLEl,FR
1753~6 ~526 )MOVE THE NEW
053~74~16767 MOV TABLEl+2,FR+2 )PAR~METERS INTO
175302 )REAL TIME
~00522 )VARIABLES
0531~2016767 MOV TABLElll~,Nl )DURING THE
. 1753~2 )TIME WHEN THE
442 )CLOCK IS OFF
RQ@GE ~21 )SO THAT THE
053110016767 MOV TABLEl+12,Nl+2 )TRANSITION
175276 )DOES NOT OCCUR
00~436 )IN THE MIDDLE
053116016767 MOV TABLEl+14,SE )OF A SAMPLE
175272 )PERIOD.
) .
~0~452 053124016767 MOV TABLE1~16,SE+2 ) : 0~446 053132016767 MOV TABLE1~34,LE
175276 .
~ 442 ~5314ddl6767 MOV TABLE1~36LE+2 - 54 - .

:` , . ' ' :

111~6Q8 ~ &~Lg 000436 )MOVE THE
053146 016767 MOV TABLEl+24,X )NEW PARA-175252 )METERS INTO
000442 )REAL TIME
~53154 016767 MOV TABLEl+26,K+2 )VARIABLES
175246 )DURING THE
000436 )TIME WHEN THE
~53162 ~16767 MOV INTSAM,INTSA )CLOCK IS OFF
. ) ` ~00506 )SO THAT THE
:; ) ~0322 )TRANSITION
053170 016767 MOV INTSA,INTS IDOES NOT OCCUR
000316 )IN THE
¦ 000312 )MIDDLE OF A
053176 016767 MOV TABLE1~20SSLSTR)SAMPLE
175216 )PERIOD.
00~434 053204 016767 MOV TABLEl+22SSLSTR+2) 053212 ~05067 CLR AVG
;~ 000412 )ZERO AVG.
053216 005067 CLR AVG+2 053222 0167~6 MOV STKST,SP
~ 000420 )RESET THE
I )STACK
~53226 ~5746 TST (SP)- ) ~;, 053230 052767 BIS #40,LKS;TURN ON THE REAL TIME
` I CLOCK.

: ' :

``` il~6~8 053236 005767 TEST: TST UPDAT;HAS A NEW FEEDRATE
BEEN CALCULATED?

~ 0~0244 053242 001003 BNE NEWDAT;YES PRINT IT
053244 000001 WAIT;NO-WAIT FOR INTERRUPT.
053246 000167 JMP TEST;RETURN HERE FROM
INTERRUPT.

053252 005267 NEWDAT: INC CR
00~160 RQ@GE 022 . 053262 001407 BEQ AB
053264 016767 MOV TEMP,TEM

. 0~0210 053272 016767 MOV TEMP~2,TEM+2 000266 )PRINT OUT
000204 )NEW FEED RATE
053300 000406 BR ABC )ON TTY;
053302 016767 AB: MOV PREV,TEM )5 PRINTOUTS
000260 )PER LINE, 000172 )WITH * IF IN
053310 016767 MOV PREVl2,TEM+2 )ACRILOK
0~254 00~166 053316 005067 ABC: CLR UPDAT
0~0164 053322 012746 MOV #BUFF,(SP)-053326 012746 MOV #14.,(SP)- ) . - 56 -.' Qt~8 00~16 053332~12746 MOV #5,~SP)- ) ~53336~5~46 CLR (SP)-~5334~~16746 MOV TEMt2,(SP)-~ 14~ ) . ~53344~16746 MOV TEM,(SP)-~132 3 d53350~4767 JSR PC,$GCO
. 006310 053354005767 . TST ACRILK
0~0226 053362012767 MOV #'*,BUFF
. . ) PRINT OUT
0~0052 ) NEW FEED
. 0~0066 I ) RATE ON TTY;

. ) 5 PRINTOUTS
. 00~212.
l ) PER LINE, WITH
1 053374022767 AC: CMP #5,CR
: ) * IF IN
: 000~05 I ) ACRILOK.
~0~34 3 -¦ 053402001~5 BNE OUT' , 053404005067 CLR CR 3 :l 00~026 ~5341~00~004 lOT
; 053412053440 .WORD CRLF
053414012 .BYTE WRITE,l 053416000004 OUT!: lOT
. RQ@GE ~23 05342005345~ .WORD BBUFF
:' . - 57 -~ 6~8 053422012 .BYTE WRITE,l )PRINT OUT NEW

)FEED RATE ON
. 053424000004 WAIT: IOT
. )TTY; 5 PRINT-053426053424 .WORD WAIT
. )OUTS PER LINE, 053430004 .BYTE WAITR,l . )WITH * IF IN
: 053431001 )ACRILOK.

; 177600 . 0534360000~0 CR 0 053440000002 CRLF: 2 :. ~534420000~0 0 ~ . ~ 0534440~00~2 2 j: 053446015 .BYTE 15,12 . 053447012 ; 053450000016 BBUFF: 14.
," 053452000000 0 ,. 053454000016 14.
. 05350Z BUFF: .-.~20.
.. ~ 053506 TEM: .=.t4 : ~ 053506000000 UPDAT: 0 053510000000 INTS: 0 )LOCATIONS
`i 053512000000 INTSA: 0 )FOR VARIABLES
~53514000000 Y: 0~0 )FLAGS, &
` 053516000000 )BUFFERS
. ~53520000000 X: 0,0 ;` ~535220000~ ) ~`` 053524~00000 X2: 0,0 05352600000~ ) ;; 053530000000 Xl: 0,0 :,`.
`: ~53532~00000 - ) ~ 053534000000 XY: 0,0 `::
. - 58 -.

06Q8 ~_. ~

~53536 ~000~ ) 053540 00~000 XYC: 0,0 053542 0000~ ) 053544 000000 - YC: 0,0 053550 000000 N: 0 053552 000000 Nl: 0~0 053556 000000 SAMS01: 0,0 053562000000 TEMP: 0,0 )LOCATIONS
053564000000 )FOR
053566000000 PREV: 0,0 )VARIABLES, 053570000000 )FLAGS, 053572000000 ERRSW: 0,0 )AND
053574000000 )BUFFERS
053576000000 SE: 0~0 RQ@GE 024 05360200000~ LE: 0~0 05360400~000 05360600000~ ACRILK: 0,0 05361000000~ ) 053612000000 LOS: 0,0 053616000000 K: 0,0 ~53620~00000 .. ) 0536220000~0 FR: 0~0 ~53624000000 053626--00000~ -CONWOR:---0 - ) 053630000000 AVG: 0,0 - 59 - .
'' `~ 6~8 053634 000000 SSLST: 0 053636 000000 SsLsTl: 0 053640 000000 SSLST~: 0,0 ) 053644 000000 LOOP: 0 - ) 053646 000000 STKST: 0 ) ) LOCATIONS
053650 000000 HOLD: ) FOn 053652 000000 HOLDl: 0 ) VARIADLES, 053654 000000 HOLD2 0 ) FLAGS, 053656 000000 HOLD3: 0 ) AND
053660 000000 HoLD4: 0 ) BUFFERS
053662 000000 HOLD5: 0 053664 000000 HoLD6: 0 053666 000000 HOLD~: 0 ) 053670 000000 HoLD8: 0 ) .
053672 000000 HOLD9: 0 ) 053674 000000 INTSAM: 0 ) ' 000001 .I~Nr) . - ) ' : ~ ' RQ~GE 025 '~; , ' .
''', . ' . . ~' .' . . ' ~: ' . .
':' .

.. . ~ ~. .
.. . . .

SYMBOL TABLE LISTING

A052164 AB ~53302 ABC053316 AC 053374 ACRILK 053606 ACRILO 052314 ASK 050~60 AVG 053630 DATAz 177552 DFLOAT 051766 ERRSW 053572 FR 053622 HOLD053650 HOLDl 053652 HOLD2053654 HOLD3 053656 HOLD4. 05366~ HOLD5 053662 HOLD6 053664 HOLD7 053666 LINK050716 LKS = 177550 LOOP 053644 LOOPl 052310 NOM2705203~ Nl053552 OFFDAC 052306 OFFSET= 177554 ONEF' 04020~ OUT177554 OUTl053416 OVER27 052012 OVR051410 PC-%000007 POS27052020 PREV 053566 RTRN052076 R0'%000000 Rl =%000001 R2 =%000002 R3=%000003 R4~%000004 R5 ~%000005 R6 _%000006 SAVl052354 SE053576 SET = 177550 SIXF - 040700 SP'%000006 SSLST053634 SSLSTR 05364~ SSLSTl 053636 TABLEl 050400 TABLE2 050472 TABLE3 050506 TABLE4 050522 TABLE5 050544 TABLE6 050570 TABLE7 0506~4 TABLE8 050630 WAIT053424 WAITR = 000004 WAITT 050116 WATHO 052226 XYC~5354~ Xl05353~ X2 .053524 Y053514 YC053544 ZER2705207i $ADR- 057452 $CMR= 060206 $DVR= 063500 $GCO= 061664 $IR~ p64146 $MLI= 064232 $MLR- 064412 $NGR- 064772 $POLSH -065146 $RCI - 060264 $RI= 065024 $SBR= 057446 .- 053676 *S

. - 61 -. .

.

1~06~8 ., From the foregoing disclosure, it can be seen that the instant invention provid~s an improved weigh feeding apparatus, wherein the discharg~ rate of a substance from a container may be maintained at a preselected constant value, wherein the container may be automatically refilled during the continuous discharge of the sllbstance, wherein excessive excursions of the system are eliminated, wherein ~-.
extraneous data recordings are eliminated when calculating the flow rate, and wherein past flow rate values may be stored in memory and compensated for at a later point in time.

Although a certain particular embodime~t of the invention has been herein disclosed for purposes of explanation, various modifications thereof, after study of the specification, will be apparent to those skilled in the art to which the invention pertains. . . .

WHAT IS CLAIMED AND DESIRED TO BE SECURED BY
~E S PATENT IS:

,,.. ' . ' .
:' :
., . .

~.
. ,.

. - . - . . .
.
, : . .

Claims (17)

The embodiments of the invention in which an exclu-sive property or privilege is claimed are defined as follows:

1. A weigh feeding machine comprising:
a container for a substance;
means for discharging substance from the container at a controllable feed-out rate;
means for sensing the weight of at least the container and any substance therein for a predetermined period of time, and for producing a succession of first electrical signals during successive instants within said predetermined period, each of said signals being indicative of a value of said weight;
a digital microprocessor and a digital memory;
means for supplying to said digital microprocessor and memory said first electrical signals and for storing said signals in said memory;
means for supplying to said digital microprocessor and memory a second electrical signal indicative of a desired feed-out rate;
means for computing a predetermined deviation from the mean value of said stored first signals and for determining how many of said first signals differ in value from said mean value by more than said predetermined deviation;
means for sensing whether the number of said deviating first signals exceeds a predetermined number;
means, operative if said number of deviating first signals does not exceed said predetermined number, for causing said digital microprocessor and memory to compute the slope of the actual feed curve and compare it with the second electrical signal to produce as a result a third electrical signal indicative of the degree of departure, if any, of the current feed-out rate from the desired feed-out rate; and means for causing the discharging means to feed out said substance at a feed-out rate determined by said third electrical signal.

2. A weigh feeding machine as in Claim 1, wherein the first electrical signals that exceed said predetermined deviation are excluded when computing the slope of the actual feed curve.

3. A weigh feeding machine as in Claim 1, further including means, operative if said number of deviating first signals does exceed said predetermined number, for producing a further electrical signal, and means including the digital microprocessor and memory, responsive to said further signal, for the operation of the third signal to thereby maintain the feed-out rate at the level thereof existing immediately before said further signal.

4. A weigh feeding machine as in any one of Claims 1 to 3 further including means for detecting forces which act on said weight sensing means and are in addition to the forces acting thereon which are due to the weight of said container and substance, and for producing a fourth electrical signal indicative of said additional forces; and means for supplying said fourth electrical signal to the digital microprocessor and memory and for causing the digital microprocessor and memory to compensate said third electrical signal for the additional forces of which said fourth electrical signal is indicative and to thereby tend to make the feed-out rate insensitive to said additional forces.

5. A weigh feeding machine as in Claim 1, which includes means for monitoring the first electrical signals and for producing a fourth electrical signal when a selected characteristic of the first electrical signals is outside a defined range and means for causing the digital micro-processor and memory to respond to said fourth electrical signal by inhibiting the operation of the third electrical signal to thereby maintain the feed-out rate at the level thereof existing immediately before said fourth electrical signal.

6. A weigh feeding machine as in Claim 1, including means for supplying said digital microprocessor and memory with a fourth electrical signal indicative of a desired minimum feed-out rate, means for causing the digital micro-processor and memory to produce an under-feed alarm signal when the feed-out rate indicated by changes in said first electrical signals fall below the minimum feed-out rate indicated by said fourth signal and means for displaying said under-feed alarm signal.

7. A weigh feeding machine as in Claim 1, including means for supplying to said digital microprocessor and memory a fourth electrical signal indicative of a maximum desired feed-out rate, means for causing the digital microprocessor and memory to produce an over-feed alarm signal when the actual feed-out rate indicated by changes in said first electrical signals exceed the over-feed rate indicated by said fourth signal and means for displaying said over-feed alarm signal.

8. A weigh feeding machine as in Claim 1, which includes means for producing an under-weight electrical signal when the weight sensed by the sensing means falls below a selected minimum weight, means for causing an automatic refill of the container with substance to a desired weight level in response to said under-weight signal and means for causing the digital microprocessor and memory to inhibit the operation of said third electrical signal to thereby maintain the feed-out rate at the level existing immediately prior to the under-weight signal at least for the duration of said automatic refill.

9. A weigh feeding machine as in Claim 8, further including means for monitoring the slope of the actual feed curve until the difference between it and the second electrical signal is less than a predetermined error limit prior to causing the automatic refill of the container with substance.

10. A weigh feeding machine as in Claim 8, which includes means for producing an over-weight electrical signal when the weight sensed by the sensing means exceeds a selected maximum weight and means for causing the digital micro-processor and memory to respond to said over-weight signal by terminating the inhibition of the operation of the third electrical signal.

11. A weigh feeding machine as in Claim 1, wherein said means for supplying to said digital microprocessor and memory said first electrical signals include:
means including said digital microprocessor and digital memory for combining the signals sensed during each such period of time with a voltage level, said voltage level being different during each such period of time to obtain a succession of difference signals, each representative of the difference in weight between one of said voltage levels and a signal representative of the instantaneous weight sensed at an instant of time, whereby said difference signals are the first electrical signals stored in said memory.

12. A weigh feeding machine as in Claim l, wherein said means for supplying to said digital microprocessor and memory said first electrical signals include amplifier means for amplifying said first electrical signal, an analog-digital converter coupled between said amplifier means and said digital microprocessor, digital-analog converter ramp offset means controlled by said digital microprocessor and having a controlled staircase-like stepping output applied as an additional input signal to said amplifier means to algebrai-cally combine with said first electrical signals, each step corresponding to one of said periods of time thereby to maintain the output of said amplifier means in a given pre-selected range of amplitude during each of said periods of time.

13. A weigh feeding machine as in Claim 12, wherein said amplifier means includes a first amplifier and a second amplifier connected in series, said digital-analog converter ramp offset means controlled by said digital microprocessor has a controlled staircase-like stepping output applied as an additional input signal to said second amplifier to algebrai-cally combine with the output of the first amplifier, thereby to maintain the output of said second amplifier in a given preselected range of amplitude during each of said periods of time.

14. A weigh feeding machine as in Claim 13, wherein said digital microprocessor and memory is adapted to integrate said second signal indicative of a desired feed-out rate with respect to time and output a display corresponding to the desired total feed commanded, and said digital microprocessor and memory being further adapted to receive and to compare the signals received from said first amplifier indicative of the actual total weight of material fed with the total feed commanded and adjust said third signal in response to a deviation exceeding predetermined limits.

15. A weigh feeding machine as in Claim 13, wherein said first amplifier means has an output voltage range of between -10 volts when the container is full to +10 volts when the container is empty.

16. A weigh feeding machine as in Claim 13, wherein said second amplifier means has an output voltage range between +5 volts and -5 volts during each period of a series of periods of time.

17. A weigh feeding machine as in Claim 1, wherein said means for discharging substance from the container includes a motor driven feeder assembly, means for inputting into said digital microprocessor and memory a fourth signal indicative of the actual speed of said motor, means for inputting into said digital microprocessor and memory a fifth signal indicative of the desired rotational speed of said motor, means for causing said digital microprocessor and memory to combine said fourth and fifth signals and to produce a sixth signal indicative of the degree of the departure, if any, from the desired motor speed, and means for causing the motor to operate at a speed determined by said sixth signal.