JPH0547425Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Field of Application] The present invention relates to a heater abnormality diagnosis device and can be used in heated parts of injection molding machines, delivery machines, etc.

[Background technology]

BACKGROUND ART Traditionally, injection molding machines, extrusion machines, and the like have melted and heated molded resin, and electric heaters with simple structure and adjustment have often been used in these parts. In electric heaters, internal wires (heating elements) may break, and when used in injection molding machines, etc., devices are used to check for breaks.

Disconnection testing equipment generally tests the current of the heater, and in addition to an ammeter connected to the power supply wiring,
Indirect means, such as examining changes in magnetic fields near wiring, are also used. In addition, some heaters have multiple internal wires connected in parallel, and even if one wire breaks, the current in the heater does not become zero. was detected to be lower than normal.

[The problem that the idea aims to solve]

By the way, the heater current fluctuates depending on the power supply voltage and may drop even if the heater is normal. Conventional disconnection inspection equipment has to tolerate fluctuations in the power supply voltage, which imposes restrictions on current detection. .

For example, a typical power supply voltage fluctuates by about 10%, and if the tolerance range is set accordingly, it will not be possible to detect individual wire breakages in heaters with 10 or more internal wires.

Furthermore, abnormalities in the heater may be caused by defects in the wiring from the power supply to the heater or in the output regulator placed in between, so it is insufficient to simply inspect the heater for disconnection using conventional disconnection inspection equipment. It is. However, the reality is that these parts are not inspected.

An object of the present invention is to provide a heater abnormality diagnosis device that can reliably make a comprehensive abnormality judgment regarding the heater.

[Means to solve the problem]

The present invention includes an ammeter that measures the current of the heater;
A voltmeter for measuring the voltage of the power source of the heater and a determining means for determining an abnormality in the system including the heater or the power source based on the current and voltage are provided, and the determining means is provided with a ratio of the current and voltage as a reference. A heater abnormality diagnosing device is constructed by providing a heater disconnection inspection section that compares the values with the values.

Here, in addition to the heater disconnection inspection section, the determination means include a power regulator normally placed between the heater or power supply, a section that inspects defects in the wiring system based on current, or a section that inspects abnormalities in the power supply based on voltage. You can use the parts that

[Effect]

In this invention, by determining the ratio of current and voltage in the heater disconnection inspection section,
Changes in the power supply voltage are canceled out, allowing only the change in current due to a disconnection to be investigated, and comparison with a reference value makes it possible to reliably inspect heater disconnections. In addition, by checking the power supply voltage from the voltmeter in addition to the heater current from the ammeter, it becomes possible to comprehensively test the system from the power supply to the wiring system and heater using the other inspection parts of the judgment means, thereby making it possible to comprehensively test the system from the power supply to the wiring system and heater. The purpose is achieved.

〔Example〕

Hereinafter, one embodiment of the present invention will be described based on the drawings.

In FIG. 1, three electric band heaters 3 are arranged in a barrel 2 of an injection molding machine 1 to melt and heat resin. Each heater 3 has a plurality of internal wires (heating elements) 4 connected in parallel, each of which is connected to an independent power source 6 via a wiring 5. A power regulator 7 for adjusting heating output is installed between each wiring 5, and a control signal from a control device 8 of the injection molding machine 1 is input to each regulator 7. The control device 8 adjusts the heating state of each heater 3 using each regulator 7, and performs zone control so that each part of the barrel 2 has an optimum temperature. A heating device 9 is constituted by these three systems of heaters 3, regulators 7, and the like.

On the other hand, a heater abnormality diagnosis device 10 based on the present invention is arranged in the heating device 9.

The abnormality diagnosis device 10 includes an ammeter 11 and a voltmeter 12 for each system, and their outputs are collectively connected to an input/output multiplexing means 13.

The ammeter 11 is connected to the wiring 5 between the heater 3 and the regulator 7, and measures the current consumption of the heater 3 and outputs it as current values _A1 to _A3 .

The voltmeter 12 is connected to the wiring 5 between the regulator 7 and the power supply 6.
is connected to the power supply 6, and measures the supply voltage of the power supply 6 to obtain the voltage value.
It outputs as _V1 to _V3 .

The input/output multiplexing means 13 outputs the current value A ₁ of each system.
~A ₃ , voltage values V ₁ ~V ₃ , and control signals D ₁ ~D ₃ from the control device 8 are collected, and each input signal is appropriately processed using an existing buffer circuit, A-D/D-A converter, etc. At the same time, the signals An,
Vn and Dn can be taken out.

Each of these signals An, Vn, and Dn is used by a determining means 20 for diagnosing abnormalities in each system based on each signal.
It is connected to the.

The determination means 20 includes a power supply abnormality inspection section 21, a wiring system abnormality inspection section 22, a current value correction calculation section 23, a heater disconnection abnormality inspection section 24, and a determination control section 25, and also sets a value that is a criterion for determination. Reference value setting means 26, display means 27 for displaying judgment results
It is equipped with

The power supply abnormality testing section 21 compares the voltage value Vn with the voltage reference value Vno from the reference value setting means 26 to test whether the power supply 6 of each system is normal.

The wiring system abnormality inspection section 22 checks that the current value An is zero, that is, there is no current between the power source 6 and the heater 3, and checks for disconnection in the wiring 5 of each system or poor contact in the switching part of the regulator 7. This is based on the knowledge that the heater 3, which has a plurality of internal wires 4, cannot all be disconnected at the same time, and that zero current flow is exclusively due to a problem with the power supply path. . Further, the wiring system abnormality inspection unit 22 detects that the control signal D ₁ is zero and the current value An is greater than zero, that is, there is current flowing to the heater 3 even though the regulator 7 is in a power cutoff state, and the switch section of the regulator 7 is detected. This is to inspect the occurrence of welding.

The current value correction calculation unit 23 calculates a correction current value A′n=An/Vn from the current value An and the voltage value Vn,
Output to inspection section 24 for heater burnout. here,
The current value An of the heater 3 changes in proportion to the supplied voltage value Vn from the power source 6, but the corrected current value A'n, which is the ratio of each, remains constant regardless of the voltage value Vn.

The heater disconnection abnormality inspection unit 24 detects the corrected current value A′n
and the corrected current reference value from the reference value setting means 26
A'no is compared to examine the decrease in current consumption of the heater 3 of each system, and to check for a decrease in the number of effective internal wires 4 due to wire breakage.

The determination control section 25 specifies the system n to the input/output multiplexing means 13 and outputs each signal An, which is to be inspected.
In addition to switching Vn and Dn, the display means 2 displays the test results from each test section 21 to 24 for these.
7, and a message corresponding to the corresponding abnormality is displayed, such as "There is a disconnection in the heater of the first system" or "The power supply voltage of the second system is abnormally low." Note that the output of the determination control section 25 is also connected to the control means 8, and in the event of an abnormality fatal to the injection molding operation, such as a disconnection of the wiring 5 that cannot be heated or a welding of the regulator 7 that cannot be controlled, the output of the determination control section 25 is also connected to the control means 8. It is possible to issue an abnormal stop command to take corrective action.

In this embodiment configured as described above, abnormality diagnosis is performed in the following procedure.

That is, a corrected current reference value based on actual measurement or theoretical value under normal conditions is set in advance in the reference value setting means 26.
A′no and the voltage reference value Vno are set, and the judgment control unit 25 specifies the system n in order.
The signals An, Vn, and Dn related to the third to third signals are taken in, and each system is tested by each testing section 21 to 24.

In the inspection for each system, as shown in Fig. 2, the power supply abnormality inspection section 21 first compares the voltage value Vn and the voltage reference value Vno (step S1), and if they do not match, it is determined that there is a "power supply abnormality". (Step S2).

If they match, the control signal Dn is inspected in the wiring system abnormality inspection section 22 (step S3), and the control signal
If there is no Dn, the current value An is checked (step S4), and if it is zero, it is determined to be "normal" (step S5), and if there is a current, it is determined to be "adjuster welding" (step S6).

On the other hand, if there is a control signal Dn in step S3, the current value An is checked (step S7), and if it is zero, it is determined that there is a "disconnection in the wiring system or poor contact in the regulator" (step S7).
S8).

If there is a current, the current value correction calculation section 23 calculates the corrected current value A'n (step S9), and the heater disconnection inspection section 24 compares it with the corrected current reference value A'no (step S9).
S10), if they match, it is determined to be "normal" (step S11),
If they do not match, it is determined that the heater is disconnected (procedure).
S12).

These results are summarized by the determination control section 25 and sent to the display means 27, where they are displayed as a corresponding message (step S13).

According to this embodiment, the following effects can be obtained.

That is, when inspecting for a disconnection in the heater disconnection inspection section 24, the current value correction calculation section 23 divides the current value An by the voltage value Vn to obtain a corrected current value A'n that offsets the voltage change, and then Since disconnection of the heater 3 is determined based on a decrease in the value A'n, accurate test results can be obtained regardless of the state of the power supply 6.

In particular, since there is no need to set a tolerance range for fluctuations in the supply voltage, it is possible to reliably capture even a small current change when one of the plurality of internal wires 4 is disconnected.

In addition, when determining a wire breakage, by preparing a normal corrected current reference value A'no in advance and comparing it with the detected corrected current value A'n, more accurate and reliable wire breakage detection can be performed. can be realized.

On the other hand, in the wiring system abnormality inspection section 22, the current value An
Based on this, it is possible to inspect for disconnection of the wiring 5 and poor contact of the regulator 7, and also to inspect for welding of the regulator 7 by checking the control signal Dn to the regulator 7. Furthermore, in the power supply abnormality inspection section 21,
By checking the voltage value Vn, an abnormality test can be performed on the power supply 6.

Therefore, in the abnormality diagnosis device 10 of this embodiment,
The ammeter 11 and the voltmeter 12 are determined by the determining means 20.
Using this, a comprehensive inspection of the system including the power supply 6, wiring 5, regulator 7, and heater 3 can be performed.

Further, the determining means 20
This makes it possible to collectively inspect the three heater systems arranged in the injection molding machine 1, and also allows the display means 2 to be inspected at once.
7, the determination results can be displayed in an easy-to-understand manner, and the heated portion of the injection molding machine 1 can be comprehensively monitored.

It should be noted that the present invention is not limited to the above-mentioned embodiments, but also includes the following modifications.

In other words, when calculating the corrected current value A'n in the current value correction calculation unit 23, the method is not limited to dividing the current value An by the voltage value Vn, but the voltage value is calculated by dividing the voltage value Vn by the voltage reference value Vno. A variation ratio may be calculated and the current value An may be multiplied by this ratio. In short, processing may be performed to cancel voltage changes when comparing currents.

Furthermore, the configuration of the determining means 20 may be selected as appropriate in implementation, and the configurations of the power supply abnormality inspection section 21 and the wiring system abnormality inspection section 22 may be appropriately changed or partially omitted.

Furthermore, the reference value set in the reference value setting means 26 may be changed to the required value in each inspection section, and the setting can be done by inputting numerical values by the operator or by making sure that the heating device 9 is in a normal state. It may also be a device that actually measures and stores the values of the ammeter 11 and voltmeter 12 according to instructions from an operator at a certain appropriate point in time.

On the other hand, the voltmeter 12 does not need to be arranged corresponding to each heater 3, and one voltmeter 12 may be used in common for testing each system, such as when the power supply 6 of each system is common.

Further, the display format on the display means 27 and the format of the abnormal stop signal to the control device 8 are also arbitrary.
Each may be modified or partially omitted in implementation.

Furthermore, an ammeter 1 used in the abnormality diagnosis device 10
1. The specific configuration of the voltmeter 12, input/output multiplexing means 13, etc. may be selected as appropriate during implementation, and the specific configuration of the injection molding machine 1, control device 8, and heating device 9 to be applied may also be arbitrarily selected. It is.

In particular, the heating device 9 to which the abnormality diagnosis device 10 is applied is not limited to one having two or more systems of heaters 3, etc., but can also be applied to one system of heaters 3, etc.
In this case, the input/output multiplexing means 13 may be omitted.

Further, the present invention is not limited to the injection molding machine 1, but can also be applied to other devices such as an extruder using a heating device.

[Effect of idea]

As described above, according to the heater abnormality diagnosis device of the present invention, it is possible to accurately and reliably diagnose disconnection of the heater, and also to perform a comprehensive abnormality diagnosis regarding the heater by simultaneously inspecting the power supply and wiring system. It can be done reliably.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing the overall configuration of an embodiment of the present invention, and FIG. 2 is a flowchart showing the inspection procedure of the embodiment. 1... Injection molding machine, 3... Heater, 4... Internal wire, 5... Wiring, 6... Power supply, 7... Regulator,
9... Heating device, 10... Abnormality diagnosis device, 11...
... Ammeter, 12 ... Voltmeter, 20 ... Judgment means,
24... Heater disconnection inspection section, 25... Current value correction calculation section.

Claims (1)

[Scope of utility model registration request] It has an ammeter that measures the current of the heater, a voltmeter that measures the voltage of the power source of the heater, and a determination means that determines an abnormality in the system including the heater or the power source based on the current and voltage from each, A heater abnormality diagnosing device characterized in that the determining means includes a heater disconnection inspection section that compares the ratio of the current and voltage with a reference value.