JP2508164B2 - Operating cycle time measuring device for multiple machines - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for automatically measuring operating cycle times of a plurality of machines.

Conventional technology It is necessary to measure the operating cycle time of a machine in order to improve the machine itself or the line in which the machine is included, collect setting data for new lines, etc. The time was measured manually. A person goes to the vicinity of the machine, looks at the work flow and the machine operation status display lamp, measures the time from the start to the end of the machine operation cycle with a stopwatch, etc. several times to 10 times, and then calculates the average value. The calculation was performed to obtain the operation cycle time.

Therefore, it is necessary for a person to go near the machine, and
Since all the work is done manually, a large number of man-hours are required, and the risk of error is high. In addition, it is difficult to obtain a highly reliable measurement result because it is difficult to increase the number of samples.

On the other hand, Japanese Patent Application Laid-Open No. 61-128648 discloses a display device for displaying the state of a specific signal among signals supplied from a plurality of machines via multiplex transmission lines. By displaying the signals of the start and end of the operation cycle of a specific machine on this display device and measuring the time from the start to the end with a stopwatch, etc., the operation cycle time of multiple machines can be measured at one place. it can.

Problems to be Solved by the Invention Therefore, it is not necessary to go to the vicinity of the machine one by one, and the number of man-hours for measuring the operation cycle time can be reduced. However, there is still a problem that it requires a considerable number of man-hours, a high risk rate that an error occurs, and it is difficult to obtain a large number of samples, so that reliable data cannot be obtained.

Means for Solving the Problems The present invention has been made in order to solve this problem with the object of obtaining an apparatus capable of automatically measuring the operation cycle time of a plurality of machines. As shown in FIG. 1, the time measuring device includes (a) each multiplex transmission channel bit and each of multiplex transmission channel bits of a signal supplied from a plurality of machines through multiplex transmission lines, which indicates the start and end of the operating cycle of each machine. Associating means for associating machines with each other, and (b) the associated multiplex transmission channel
A clock means for monitoring the signal of the bit and measuring the operation cycle time from the start to the end of the operation cycle; and (c)
It is configured to include a storage unit that stores the operation cycle time measured by the time counting unit in association with each machine.

The time measuring means may measure the operation cycle time of one machine at one time, but it is a method that measures the operation cycle time of a plurality of machines at one time in a time-division manner. Desirable for improvement. Also, the measured operating cycle time is printed as is,
Alternatively, it may be displayed on a display, but it is desirable that the necessary processing is automatically performed before outputting.
For example, the timekeeping means performs timekeeping for a plurality of operating cycles of each machine, and the storage means stores a fixed number smaller than the number of times of measurement among the measurement results of the plurality of times, in order from the smallest value, It is recommended to calculate the average value.

Action and Effect In the operation cycle time measuring device configured as described above, the operation cycle time of one or a plurality of machines is measured at one time. In the latter case, the efficiency of measuring the operating cycle time is particularly improved, but even in the former case, the operating cycle time is measured manually by a stopwatch, etc. The effect is obtained.

In addition, since the measurement is automatically performed in both cases,
The risk of error occurrence is lower than in the case of manual operation, and since it is easy to increase the number of samples, a reliable operation cycle time can be obtained.

Particularly, when the storage means stores only a fixed number of data in order from the shortest one among the plurality of measured operation cycle times, an effective operation cycle time can be easily obtained. That is, in general, the operating cycle time of a machine includes extensions due to various causes, and it is desirable to exclude these extensions in order to obtain a true operating cycle time. By selecting the shortest possible measurement result from a plurality of operation cycle times, it is unlikely that they include the extension time, and a measurement result close to the true value can be obtained.

Embodiment FIG. 2 shows a control system suitable for installing an operating condition monitoring apparatus which is an embodiment of the present invention. This control system is a system in which a large number of machines are time-division controlled by a sequence controller 10 via multiplex transmission lines 12. To the multiplex transmission line 12, a master control unit 14 that controls the channel of the transmission line 12, a transmission unit 16 and a reception unit 18 arranged in each machine are connected. A multiplex transmission interface 20 has a function of converting a serial signal into a parallel signal and vice versa.

The master control unit 14 includes a channel counter 22. The channel counter 22 counts the pulse signal supplied from the oscillator 24, and outputs a channel count pulse to the multiplex transmission line 12 every time the count value reaches a certain value. A comparator 26 is connected to the channel counter 22. When the value set in the register 30 by the operation of the dip switch 28 becomes equal to the count value of the channel counter 22, the comparator 26 Supply a reset pulse to 12. While the channel count pulse is a positive pulse, the reset pulse is a negative pulse, so that both pulses can be distinguished.

The transmission unit 16 also includes a channel counter 36, and counts channel count pulses received from the multiplex transmission line 12 via the line driver receiver 38.
A comparator 40 is connected to the channel counter 36, and when the value set in the register 44 by the DIP switch 42 becomes equal to the count value of the channel counter 36, a high level signal is supplied to the AND circuit 46. . A plurality of switches 48 attached to the machine are connected to the AND circuit 46 via a latch 50 and a parallel / serial converter 52. A high-level signal (hereinafter, referred to as an ON signal) or a low-level signal (hereinafter, referred to as an OFF signal) supplied in accordance with the operation state of the plurality of switches 48 is held in a latch 50, Converted to a serial signal,
This is to be supplied to the AND circuit 46.
The AND circuit 46 controls each machine in which the channel number of the multiplex transmission line 12 specified by the master control unit 14 is set in the register 44 of the transmission unit 16 while the ON signal is supplied from the comparator 40. While the signal is equal to a value specific to the switch, a signal regarding the operation status of the switch 48 is supplied to the multiplex transmission line 12 via the line driver receiver 38.

The receiving unit 18 also has the same configuration as the transmitting unit 16, and while the channel number of the multiplex transmission line 12 designated by the master control unit 14 and the value unique to each machine registered in the register 58 are equal. , The signal from the multiplex transmission line 12 is received by the line receiver 56,
The various output devices 60 are operated based on the signal.

Then, the sequence controller 10 receives the signal supplied from the transmission unit 16 of each machine via the multiplex transmission interface 20, and conversely, receives the signal of each machine via the multiplex transmission interface 20 and the multiplex transmission line 12. Unit 18
A plurality of machines are controlled in a time-sharing manner by supplying command signals to a plurality of machines. Since the sequence controller 10 and the multiplex transmission interface 20 are well known and are not indispensable for understanding the present invention, detailed description will be omitted.

An operating condition monitor device 66 (hereinafter, simply referred to as monitor device 66), which is an embodiment of the present invention, is connected to the multiplex transmission line 12 together with an ANDON 68 and an ANDON control panel 70 as shown in FIG. The ANDON 68 is connected to the multiplex transmission line 12 via the receiving unit 72, and displays the operating statuses of a number of machines connected to the multiplex transmission line 12 with red, yellow and white lamps. A red lamp indicates a mechanical abnormality, a yellow lamp indicates that a worker is being called, and a white lamp indicates that some processing is being performed. The ANDON control board 70 creates a signal for turning on the above-mentioned lamps of three colors based on various signals supplied from the transmission unit 16 of each machine through the multiplex transmission line 12. The three-color lamps are turned on corresponding to the numbers displayed on the ANDON 68, so that the operating statuses of many machines are displayed at one place.

The signals sent from the transmission unit 16 of each device as data indicating the operation status of the machine are the signal of the entrance work presence, the machine abnormality signal, the tool change forecast signal, the quality check forecast signal and the exit full work signal shown in FIG. 6 kinds of signals, namely, these 5 kinds of signals and the process abnormality signal created in the ANDON control panel 70, are supplied to the monitor device 66 as the operation status data representing the operation status of each machine. The entrance work presence signal is a signal output from the limit switch 76 installed at the entrance of the machine,
Work 80 waiting on the conveyor 78 at the entrance of the machine 74
Indicates that there is. The tool change forecast signal is a signal output from the control panel of the machine 74, and is a signal indicating that the tool change is to be performed in the machine 74. The quality check forecast signal is output from the conveyor control panel 84 of the conveyor 82 on the exit side of the machine 74, and indicates that the quality of the product processed by the machine 74 is to be checked. The exit full work signal is
It shows that the work after the processing by the machine 74 is waiting on the conveyor 82 by the maximum planned number. As for the process abnormality signal, the signal with the inlet work is ON and the signal with the outlet full work is
A signal that turns on when a certain period of time has passed or the machine abnormality signal is on, and indicates that some abnormality has occurred in the process of the machine 74 itself that is currently being monitored. Is. On the other hand, the OFF state of the signal with the entrance work (the state without the entrance work) and the ON state of the exit full work signal are signals indicating abnormalities in the preceding process and the following process, respectively.

The monitor device 66, based on the six types of signals,
This is for automatically measuring the stop time of each machine connected to the multiplex transmission line 12 for each machine and for each cause, and for automatically measuring the operation cycle time of the selected specific machine.
As shown in FIG. 5 and FIG.
90, a monitoring interface 92, a personal computer 94, a printer 96, a CRT display 98 and a keyboard 100.

The multiplex transmission interface 90 receives the status data from the multiplex transmission line 12 and transmits it to the monitoring interface 92.
The monitoring interface 92
The status data buffer 106 is a memory for holding the input status data. In addition, the stop counting unit 10
8 is the status data buffer 10 corresponding to the multiplex transmission channel bits stored in the stop count signal table 110.
The situation data in 6 is processed according to the program described in detail later, and the machine stop time according to cause is measured for each machine. All machines connected to the multiplex transmission line 12 (maximum 20
A round of processing for 0 units is performed every second.

The signal allocation table 114 of the personal computer 94 is a memory for storing the correspondence between various signals output from the transmission unit 16 of each machine 74 and multiple transmission channel bits,
This signal allocation table 114 is created by the personal computer 94 based on the input data from the keyboard 100, and is changed by the operation of the keyboard 100 as needed. An example of the signal allocation table 114 is shown in FIG. From this signal allocation table 114, the machine abnormality signal of the machine TS1915 is assigned to the 5th bit of the 54th channel, and its logical value is 1
It can be seen that it is (ON) and the timer value of the machine TS1915 is 36 seconds. The logical value is the logical value of each signal. For example, if the 5th bit of the 54th channel is in the ON state, the machine TS
The machine abnormality signal is being emitted from 1915. Also, the timer value is the nominal cycle time of each machine.

The correspondence relationship between the multiplex transmission channel bit and the logical value and the timer value in the signal allocation table 114 is also stored in the stop count signal table 110 of the monitoring interface 92, and the stop count unit 108 uses this stop count signal. The operation status data corresponding to each multiplex transmission channel bit in the signal table 110 is read from the status data buffer 106, and the machine stop time is measured by machine and cause by executing the program represented by the flowchart of FIG. .

The monitoring interface 92 further includes a cycle time measuring unit 120. The cycle time measuring unit 120 stores the operation status data in the status data buffer 106 corresponding to the numbers of the multiplex transmission channel bits stored in the cycle time measurement signal table 122 as illustrated in FIG. , And the operation cycle time of each machine is measured according to the program represented by the flowcharts of FIGS. 9 and 10. The number of multiple transmission channel bits stored in the cycle time measurement signal table 122 is input from the keyboard 100,
This is the number of the multiplex transmission channel bit assigned to the entry work existence signal of each machine set in the cycle time measurement machine setting unit 124 in the personal computer 94.

 The operation of the monitor device 66 will be described below.

First, the measurement of the machine stop time will be described with reference to the program of FIG. Step S1 (hereinafter simply S1
It is represented by. In other steps as well), it is determined whether or not the entrance work present signal is in the OFF state. If the result of the judgment is YES, the content of the entrance work non-working timer is increased by 1 second in S2. , The judgment result is
If NO, the timer is cleared in S3. Every time there is no inlet work, the duration of that state is measured.

Then, by executing S4 to S6, the duration of the state in which the exit full work signal is ON is measured.

Next, in S7, it is determined whether the process abnormality signal is in the ON state, and if it is in the ON state, it is determined in S8 whether the quality check forecast signal is in the ON state. If it is in the ON state, the contents of the machine stop time storage area due to the quality check of the machine stop time memory is increased by 1 second in S9. That is, when the process abnormality signal is generated while the quality check forecast signal is being output, the duration of the process abnormality signal is measured as the machine stop time due to the quality check.

Similarly, in S10 and S11, the machine stop time due to the tool change is measured, and in S12 and S13, the machine stop time due to the mechanical abnormality is measured. Then, if the process abnormality signal is in the ON state, but neither the quality check forecast signal, the tool replacement forecast signal, nor the machine abnormality signal is output, the machine stop time due to other abnormality is measured in S14.

Further, if the determination result in S7 is NO, that is, if the process abnormality signal is not output, whether or not the time without inlet work has exceeded in S15, that is, whether the time measured in S2 exceeds the timer value in FIG. Whether or not it is determined is determined, and if the determination result is YES, it is measured as the machine stop time due to the absence of the inlet work. If the determination result in S15 is NO, it is determined in S17 whether the exit full work time has exceeded, that is, whether the time measured in S5 has exceeded the timer value in FIG. If the result of the determination is YES, the machine stop time due to the exit full work is measured in S18.

By the above execution, the machine stop time based on each cause of quality check, tool change, machine abnormality, other abnormalities, no entry work, and exit full work is measured independently, and it corresponds to each cause of machine stop time memory. Stored in the storage area. As is clear from the above process flow, each cause of the machine stop is given priority in the above order, and for example, when the quality check forecast signal and the tool change forecast signal are issued at the same time. As long as the quality check forecast signal is issued, machine downtime is measured as attributable to the quality check.

The time measured as described above is printed out from the printer 96 via the personal computer 94 or displayed on the CRT display 98.

Next, the measurement of the operation cycle time will be described.
As shown in Fig. 11, this measurement shows
It measures the time interval from ON to OFF. As shown in FIG. 4, the time when the work 80 waiting at the entrance of the machine 74 is introduced into the machine 74 is the operation cycle start time for the work, and the next work 80 is introduced into the machine 74. Since the time can be regarded as the end time of the operation cycle for the previous work, the operation cycle time of the machine 74 can be obtained by measuring the time interval of the change time of the signal with the entrance work present from ON to OFF. is there. As shown in FIG. 12, ten measured operation cycle times are stored in the cycle time memory of the cycle time measuring unit 120 in order from the smallest value. Then, when an operating cycle time shorter than the stored operating cycle time is obtained, the longest operating cycle time is deleted and the newly obtained operating cycle time is inserted into an appropriate position. The measurement and rearrangement of the operation cycle time will be described with reference to FIGS. 9 and 10.

First, regarding the measurement of operating cycle time,
In S31 of FIG. 9, the multiplex transmission channel bits and theoretical values are read from the cycle time measurement signal table 122. This reading is performed in order from the column with the smallest No in the cycle time measurement signal table 122 of FIG. And S32
In the No. column read in
Whether or not the bit is set is judged, but since it is usually set initially, this judgment result is YE.
It becomes S, and it is judged whether or not the entry work presence signal of the multiplex transmission channel bit read in S33 is in the OFF state.

Then, if it is in the OFF state, it is determined in S34 whether the signal data flag is set, and if it is set, the steps from S35 onward are executed, but if not set, these steps are bypassed. S4
The process for the next machine of 2 is performed. The signal data flag is set in S43 when the determination result in S33 is NO, and the determination result in S34 is Y.
Since it is reset in S35 immediately after becoming ES, only when the signal with the inlet work change from ON to OFF, S
35 to S41 will be executed.

After the signal data flag is reset in S35 as described above, it is determined in S36 whether or not the in-measuring flag is set, and if it is set, the cycle time timer is stopped in S37 and the data in S38 is set. However, if the flag during measurement is not set, bypass S37 and S38.
The cycle time timer is reset in S39 and S
At 40, the cycle time timer is started, and at S41 the measuring flag is set. That is, the timer is reset in S39 and the timer is started in S40, and the measurement in progress flag is not set until S37.
The timer stop and the data storage of S38 are not performed. This prevents erroneous measurement of the first operating cycle time for a particular machine.

The same processing as above is performed for all the set machines, and the operation cycle time is measured in parallel for a plurality of machines. In this embodiment, 8
It is possible to set one machine, and the operation cycle time is sequentially measured for the No. 1 to No. 8 columns of the cycle time measurement signal table 122 in FIG.

However, if neither machine is set and the multiplex transmission channel bit is not set in the No. 1 column of the cycle time measurement signal table 122, the judgment result in S32 is NO, and the measurement is made in S44. The middle flag is reset, and in S45, all the measurement data in the cycle time memory are cleared. When only one machine is set, the determination result of the step corresponding to S32 in the second processing flow is NO, and at the step corresponding to S45, N of the cycle time measurement signal table 122 is displayed.
The measurement value of the operation cycle time after the part corresponding to the o2 column is cleared. The same applies to the following columns. In the embodiment shown in FIG. 8, Nos. 6, 7 and 8 are used.
The measurement value of the operation cycle corresponding to the column of will be cleared.

The data storage in S38, that is, the selective storage of data, the rearrangement, and the calculation of the average value are performed according to the program represented by the flowchart of FIG. First, in S51, it is determined whether or not the measured value is already stored in the 10th column of the table shown in FIG. 12 in the cycle time memory, and if it is stored, the measured value of the cycle time timer is determined in S52. Is determined to be smaller than the tenth measured value, and if smaller, the measured value of the cycle time timer is replaced with the tenth measured value in S53. Then, in S54, the measurement values are sorted in ascending order, and in S56, the average value is calculated.

If the result of the determination in S52 is NO, that is, if the value of the cycle time timer is larger than the 10th measured value,
By bypassing the steps of S53 to S55, the data storage processing ends.

Further, if the determination result of S51 is NO, that is, if the 10th measurement value is not yet stored, S52 is bypassed and S53 is executed, and the measurement value of the cycle time timer is unconditionally 10th. It is stored as a measurement value. Then S5
The rearrangement of the measured values in 4 and the calculation of the average value in S55 are performed in the same manner as when 10 measured values are already stored.

As described above, this embodiment provides the monitor device 66, which automatically measures the stop times of all the machines connected to the multiplex transmission line 12 according to the causes, with the additional function of measuring the operation cycle time. That is, the portion of the monitor device 66 that measures the operating cycle time is the operating cycle time measuring device that is an embodiment of the present invention. Then, the signal allocation table 114, the cycle time measurement machine setting unit 124, and the cycle time measurement signal table 122 indicate that there is an entry work present signal and multiple transmission channel bits as signals representing the start time and the end time of the operation cycle of the machine. Cycle time measuring unit
In the flow chart of FIG. 9 of 120, the part for executing each step except S38 constitutes the time measuring means, and the part for executing S38 constitutes the storing means.

Another embodiment of the present invention is shown in FIG. In the operation status monitor device 130 of this embodiment, the cycle time clock unit 131 and the cycle time measurement signal table 122 are provided in the multiplex transmission interface 132, and the cycle time data selection storage / calculation unit 134 is provided in the monitoring interface 136. It is provided in. The other points are similar to those of the first embodiment.

The multiplex transmission interface 132 is similar to the normal multiplex transmission interface in that the serial / parallel converter 138
And a data holding buffer 140, the serial signal sent via the multiplex transmission line 12 is converted into a parallel signal by the serial / parallel conversion unit 138, and the converted operation status data is stored in the data holding buffer. Held at 140. The cycle time timer 131 monitors the data corresponding to the multiplex transmission channel bits set in the cycle time measurement signal table 122 from among the operation status data held in the data holding buffer 140, and The operation cycle time is measured in the same manner as in the first embodiment. The measured operation cycle time data is sent to the cycle time data selecting / storing / calculating section 134, processed in the same manner as in the above embodiment based on the flowchart of FIG. 10, and stored in the cycle time memory.

The present embodiment has an advantage over the previous embodiment in that there is no time measurement error due to the communication timing between the multiplex transmission interface and the monitoring interface, and an accurate operation cycle time can be obtained. In the above-mentioned embodiment, when the operation status data in the multiplex transmission interface 90 is to be transferred to the status data buffer 106 in the monitoring interface 92, it is necessary to wait until both are ready. Since the operating cycle time is measured by using the status data stored again in the data buffer, the error causes a large factor. On the other hand, in the present embodiment, since the multiplex transmission interface 132 itself measures the operation cycle time, there are few factors of error and an accurate measured value of the operation cycle time can be obtained.

Although the two embodiments of the present invention have been specifically described above, these are literally examples, and the present invention may be carried out in various modified and improved modes based on the knowledge of those skilled in the art. You can

[Brief description of drawings]

FIG. 1 is a block diagram conceptually showing the structure of the present invention. FIG. 2 is a block diagram showing a control system suitable for connecting an operation status monitoring device having an operation cycle time measuring function according to an embodiment of the present invention. FIG. 3 is a perspective view showing the operation status monitoring device together with ANDON and the ANDON control panel. FIG. 4 is a diagram showing signals supplied to the operating condition monitoring device. FIG. 5 is a block diagram of the operating condition monitoring device. Sixth
The figure is a diagram showing an example of the signal allocation table in FIG.
FIG. 7 is a flow chart showing a control program of the stop counting section in FIG. FIG. 8 is a diagram showing an example of the cycle time measurement signal table in FIG.
FIG. 9 is a flow chart showing the control program of the cycle time measuring unit in FIG. 5, and FIG. 10 is a flow chart of the data storing step in FIG.
FIG. 11 is a diagram showing the relationship between the inlet work presence signal and the operation cycle time in FIG. FIG. 12 is a diagram showing an example of the contents of the cycle time memory in the cycle time measuring unit 120 of FIG. FIG. 13 is a block diagram of an operating condition monitoring apparatus which is another embodiment of the present invention. 12: Multiplex transmission line 66: Operating status monitor device 76: Limit switch 90: Multiplex transmission interface 92: Monitoring interface 106: Status data buffer 120: Cycle time measurement unit 122: Cycle time measurement signal table 124: Cycle time measurement Machine setting unit 130: Operation status monitoring device 131: Cycle time clock unit 132: Multiplex transmission interface 134: Syqm time selection storage / calculation unit 136: Monitoring interface 140: Data holding buffer

Claims (2)

(57) [Claims] 1. Corresponding means for associating each machine with each multiplex transmission channel bit of a signal indicating the operation cycle start and operation cycle end of each machine supplied from a plurality of machines via a multiplex transmission line, and the correspondence. By correlating the operation cycle time measured by the time measurement means for monitoring the operation cycle time from the start to the end of the operation cycle by monitoring the signal of the attached multiple transmission channel bits, An operating cycle time measuring device for a plurality of machines, comprising: a storing means for storing. 2. The time measuring means measures time for a plurality of operation cycles of each machine, and the storage means has a constant value smaller than the number of times of measurement among the measurement results of the plurality of times, in order from the smallest value. The operating cycle measuring device according to claim 1, wherein the operating cycle measuring device stores only the number of pieces.