GB2312054A - A food handling control system - Google Patents

Abstract

A food handling control system (1) has various sensors and control units (3-7) in a food handling environment. Parameter values are routed to an on-site monitoring system (9) which logs the data in real-time sequential order. It also checks for wide divergence from control conditions and generates an early alarm. A data communications controller (10) routes data to a status process (11) which generates control signals for the control units. The data communications controller (10) has a sample and hold circuit for receiving parameter values and a parallel alarm monitor for bypassing the sample and hold circuit to route an alarm signal from a sensor directly to the status processor (11).

Description

"A food handling control system The invention relates to a food handling control system.

There are various factors which adversely affect the characteristics of food products while they are being handled. These factors include undesirable temperature variations, which in some cases can lead to development of microbial organisms and increased bacteria counts.

In some food handling systems there is a wide variety of food products stored in a particular warehouse. For example, certain warehouses may contain up to twenty separate storage bays which can be divided by differing types of product. Different temperature zones occur within the buildings, depending on how the buildings are divided and on the products stored. In certain locations, there may be a requirement for products to be stored at between OOC and +2"C, whereas in other locations, the temperature must be maintained at less than 15 C.

A number of food handling control systems have been developed such as those described in British Patent Specification Nos. GB 2133304 and GB 2131962. These describe a method and apparatus for mixing different types of grains at a desired ratio. While these systems deal with specific grain handling mixing problems apparently quite well, they do not address the general food handling control requirements in an environment where there is a wide variety of different foods being handled.

The invention is directed towards providing a food handling control system which provides comprehensive control for a wide variety of different foods stored at a location.

According to the invention there is provided a food handling control system comprising: food handling control units; food parameter sensors; a status processor; an on-site monitoring system connected to the control unit and the sensors and comprising means for logging parameter values received from the sensors in real time sequential order; a data communications controller connected to the on site monitoring system on one side and to the status processor on the other, and comprising: communication means for transmitting parameter values to the status processor and transmitting control signals generated by the status processor to the control units; and a data acquisition device connected to the sensors for capturing food handling parameter values from the sensors, the data acquisition device comprising a sample and hold circuit for receiving the parameter values, and a parallel alarm monitor comprising means for detecting an error condition in a sensor and means for bypassing the sample and hold circuit to route an alarm signal responsive to a sensor alarm condition directly from the sensor to the status processor in real-time.

The combination of the on-site monitoring system and the data communication controller provide comprehensive control with extensive recorded data and rapid alarm response. The sample and hold circuit provides a very reliable and effective means for data acquisition to enable routing to the status processor.

In one embodiment the on-site monitoring system comprises means for automatically comparing received parameter values with pre-set wide reference ranges, and means for generating an early alarm signal if a parameter value falls outside of a wide reference range, and for signalling such an event to the status processor via the data communications controller. Thus, the on site monitoring system acts to filter parameter values, thus ensuring quick corrective action on-site and also helping to maintain data integrity in the status processor.

Preferably, the means for bypassing the sample and hold circuit comprises means for addressing each sensor.

In one embodiment, the means for bypassing the sample and hold circuit comprises a logical OR gate having at least two inputs, each input being connected to a sensor.

In another embodiment, the sample and hold circuit comprises a CMOS multiplexer, a sample and hold amplifier, an analog to digital converter, and a data buffer connected to the communication means.

Preferably, the sample and hold amplifier is a programmable data amplifier.

In another embodiment, the OR gate is connected to a transmit control unit and to the data buffer in parallel.

In one embodiment, the communication means is of the data communications controller comprises a decoder connected to a drive logic circuit for transmission of control signals to the control units.

The invention will be more clearly understood from the following description of some embodiments thereof, given by way of example only, with reference to the accompanying drawings, in which: Fig. 1 is a schematic diagram illustrating a food handling control system of the invention; and Fig. 2 is a block diagram illustrating a data communications controller of the system.

Referring to the drawings, and initially to Fig. 1, there is shown a food handling control system 1 of the invention. The system 1 comprises a number of food handling control units and sensors mounted on-site at food handling warehousing locations. Sensors include a weighbridge 3 and a temperature recorder 5 and control units including coolers 4, heaters 6, and an electrohumidifier 7. These are connected by a switch 2 to a communications rack 8, in turn connected to an on-site monitoring system 9. The rack 8 and the monitoring system 9 are connected to a data communications controller 10, illustrated in more detail in Fig. 2.

The controller 10 is in turn connected to a status processor 11 which is programmed to process food handling parameter values received from the sensors and to generate control signals for the control units. The status processor 11 is connected to a number of operator interfaces 12, a modem 13 for remote communications, and to a printer 14 for hard copy print-outs.

The system 1 operates by, in real time, logging parameter values received from the sensors to a database of the on-site monitoring system 9. This data is logged in time stamp sequence with relatively little processing, the purpose being to provide a data log without complex data processing. However, an important aspect of the on-site monitoring system 9 is that it carries out simple processing operations to verify the parameter values from each sensor to ensure that they fall within pre-set wide ranges. If a parameter value exceeds a pre-set wide range, then an early alarm signal is generated by activation of a sound emitter on-site by the monitoring system 9. In practice, these alarm outputs often indicate mundane faults such as errors in the sensors, rather than major parameter changes in the food being handled. This is because the pre-set wide ranges are very wide and it is highly unusual for the parameters to fall outside these ranges. In effect, the on-site monitoring system 9 acts as a filter, which not only raises an alarm on-site, but also transmits data relating to the alarm to the status processor 11 via the controller 10.

The "raw" sensor data is also received at the data communications controller, which in turn routes the data to the status processor 11 in the correct format. The status processor 11 carries out complex processing operations and generates control signals for the various control units. It must be appreciated that the sensors and control units illustrated in Fig. 1 are in a relatively simple arrangement, for clarity. In practice, there will be many more sensors and control units and accordingly operation of the router 2 is very important. An important aspect of the invention is the fact that the data is processed very quickly to provide a real-time output, even though many of these operations are complex as they involve inter-relationships of different parameter values. For example, the temperature setting for a particular location in a warehouse would depend not only on the sensed temperature, but also on the detected humidity and on air flow rates. Achievement of this real-time aspect for generation of the control signals is due mainly to the construction of the data communications controller 10.

In addition to routing parameter values, the controller 10 also routes alarm outputs generated by the sensors in a very fast manner.

Referring to Fig. 2, the data communications controller 10 is now described in detail. The controller 10 comprises a data acquisition device 15, a communication device 16 and a drive control circuit 17.

In more detail, the data acquisition device 15 comprises a sample and hold circuit provided by a CMOS multiplexer 18, a sample and hold amplifier 19, an analog to digital converter 20 and an eight bit buffer 21. The data acquisition device also has an alarm monitor wired in parallel with the sample and hold circuit provided in this case by a sixteen input OR gate 22.

The communication device 16 comprises a transmit control unit 30 and associated transmit register 31 and a receive control unit 33 with an associated receive register 34.

The drive control circuit 17 has a decoder 40 and a drive logic circuit 41.

The CMOS multiplexer 18 has a sixteen bit input port 100. Each of the sixteen inputs is connected to sensors to monitor status data relating to humidity, temperature, volume or weight of food. Further, sensors may be monitored by use of a channel input 101 to select a given bank of sensors to be monitored at the sixteen bit input port 100. In this way, a large number of sensors may be monitored using the system 1. The CMOS multiplexer 18 has an output pin connected to the sample and hold amplifier 19. The sample and hold amplifier 19 has an gain control pin 166 to control gain of the amplifier. This is particularly useful for distributed systems where signal strength between the multiplexer 18 and the sample and hold amplifier 19 may be weakened due to increased distance. The sample and hold amplifier 19 has an output pin connected to an input pin of the analog to digital converter 20 by a conductor 113. The analog to digital converter 20 has an output port connected to an input port of the eight bit buffer 21 by a data bus 117. The data bus 117 is also connected to an input port of a disk storage device 119.

The sixteen bit input OR gate 20 has an input port connected by an error bus 121 to a bank of alarm sensors. The alarm sensors indicate an alarm condition such as insufficient volume, excessive humidity, excessive temperature, to monitor any condition which may adversely effect the operation of the food handling system. Some sensors may be connected to both the gate 22 and to the multiplexer 18. The gate 22 has an output pin connected to an active low input pin 127 of the transmit control unit 30, to an active low receive control input pin 128 of the receive control unit 33 and to an active low buffer enable pin 129 of the eight bit buffer 21.

The transmit control unit 30 has an eight bit input port connected to an eight bit output port of the buffer 21 by a data bus 152. The transmit control unit 30 also has an eight bit output port connected to an input port of the transmit register 31 by a transmit bus 155. The transmit register 31 converts data from parallel to serial and transmits status or error information to the status processor 11 through an output port 160. The receive control unit 33 receives data from the status processor 11 via the receive register 34 and a receive bus 167. The receive control unit 33 also has an output port connected to an output bus 171, in turn connected to an input port of the decoder 40. The decoder 40 has an output port connected to an input port of the drive logic circuit 41 by a drive bus 182. Outputs from the drive logic circuit 41 are communicated to control units.

In use, parameter values of the food are selectively accessed by the CMOS multiplexer 18 through the sixteen bit input port 100. If it is necessary to have more than sixteen sensors attached, there may be more than one channel and channels may be selected by the channel select input 101. The CMOS multiplexer 18 selects one of the sensors attached to the input port 100 and passes the analog signal to the sample and hold amplifier 19.

The sample and hold amplifier 11 takes the value from the input pin and produces a stationary output at the output pin. A gain may be programmed into the amplifier 19 using the gain control pin 166 to manipulate the result to be in any suitable range. The result held at the output pin is passed to the input pin of the analog to digital converter 20 along a conductor 113. The analog to digital converter 20 converts the held value from the sample and hold amplifier 19 into an eight bit digital signal and the result is placed on the output port 115. The result on the output port 19 is made available to the input port of the eight bit buffer 21 on the data bus 117 and also to the disk storage device 119 so that values may be stored and made available for transmission to the status processor 11.

When a value is made available for transmission it is received by the transmit control unit 30 through the eight bit input port and passed to the transmit register 31 signalling the status processor 11 of a transmission start. The value is received into the input port 154 of the transmit register 31 along the transmit bus 155 and converted from parallel to serial data. This value is then transmitted to the status processor 11 through the output port 160.

When the status processor 11 generates a control signal based on the values received such as to switch on a heater or electro-humidifier the receive control unit 33 receives data relating to the required action from the status processor 11 through the receive register 34.

The receive register 34 converts the serial data into a parallel data word and transmits the word through the receive bus 167 to the input port of the receive control unit 33. The receive control unit 33 then places a value on the output port activating the output bus 171 to communicate the value to the input port of the decoder 40. The decoder 40 takes the value from the input port and decodes it to place an associated value on the output port. This value is then passed to the input port of the drive logic circuit 41 by the drive bus 182. The outputs from the drive logic circuit 41 based on the received value produce the required response in the required control unit.

If an error is detected by one of the alarm sensors the signal is passed to the sixteen bit input OR gate 22 along the error bus 121. The sixteen input OR gate 22 then changes the output on the output pin to a logic 1 disabling the active low input pin 127 of the transmit control unit 30 and the active low receive control input pin 128 of the receive control unit 33. The active low buffer enable pin 129 of the eight bit buffer 21 is disabled allowing the dataword from the alarm sensors to be read directly from the error bus 121 through the error input port 200. The active low input pin 127 of the transmit control unit 30 and the active low receive control input pin 128 of the receive control unit 33 are edge triggered and thus only temporarily disabled. This allows immediate transmission of error conditions from the alarm sensors to the status processor by providing the facility for the system 1 to interrupt existing communications. The value received at the error input port 200 is then transmitted to the status processor 11 as described above and the status processor may respond to the alarm using the drive circuitry, also as described above.

The manner in which the data communications controller 10 operates to by-pass the sample and hold circuit is very important at achieving a fast response to sensor error signals. The controller 10 also operates very effectively at interfacing between the sensors and control units on one side and the status processor 11 on the other.

It will therefore be appreciated that the invention provides a food handling control system which allows calibration, monitoring and control of various devices in a food handling environment in a real-time manner.

It allows utilisation of space within a warehousing environment while monitoring not only physical parameters relating to the food, but also the locations, represented by bays. This helps to reduce damage to food and improves efficiency. The early warning system provided by the on-site monitoring system 9 complements operation of the status processor 11 in a very effective manner for comprehensive control. The status processor 11 incorporates test algorithms for each warehouse bay, which algorithms may be selected by an operator using an interface 12 using a graphical interface representing the warehouse layout. The alarm devices, not shown, in the warehouse, may include light sources which can be controlled by the status processor 11 to operate at certain wavelengths according to the information to be communicated. Such light sources may comprise for example a video display which is controlled to indicate change in colour from green to red in a particular manner to indicate the importance of the alert.

The invention is not limited to the embodiments hereinbefore described, but may be varied in construction and detail.

Claims (9)

1. A food handling control system comprising: food handling control units; food parameter sensors; a status processor; an on-site monitoring system connected to the control unit and the sensors and comprising means for logging parameter values received from the sensors in real time sequential order; a data communications controller connected to the on-site monitoring system on one side and to the status processor on the other, and comprising communication means for transmitting parameter values to the status processor and transmitting control signals generated by the status processor to the control units; and a data acquisition device connected to the sensors for capturing food handling parameter values from the sensors, the data acquisition device comprising a sample and hold circuit for receiving the parameter values, and a parallel alarm monitor comprising means for detecting an error condition in a sensor and means for bypassing the sample and hold circuit to route an alarm signal responsive to a sensor alarm condition directly from the sensor to the status processor in real-time.

2. A system as claimed in claim 1, wherein the on-site monitoring system comprises means for automatically comparing received parameter values with pre-set wide reference ranges, and means for generating an early alarm signal if a parameter value falls outside of a wide reference range, and for signalling such an event to the status processor via the data communications controller.

3. A system as claimed in claims 1 or 2, wherein the means for bypassing the sample and hold circuit comprises means for addressing each sensor.

4. A system as claimed in any preceding claim, wherein the means for bypassing the sample and hold circuit comprises a logical OR gate having at least two inputs, each input being connected to a sensor.

5. A system as claimed in any preceding claim, wherein the sample and hold circuit comprises a CMOS multiplexer, a sample and hold amplifier, an analog to digital converter, and a data buffer connected to the communication means.

6. A system as claimed in claim 5, wherein the sample and hold amplifier is a programmable data amplifier.

7. A system as claimed in claims 5 or 6, wherein the OR gate is connected to a transmit control unit and to the data buffer in parallel.

8. A system as claimed in any preceding claim, wherein the communication means is of the data communications controller comprises a decoder connected to a drive logic circuit for transmission of control signals to the control units.

9. A system substantially as hereinbefore described, with reference to and as illustrated in the accompanying drawings.