JP3728953B2 - Sequence control device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a sequence control apparatus having a function for forcibly advancing a sequence.
[0002]
[Prior art]
Conventionally, in an apparatus equipped with an actuator, the limit and return limit of the actuator are detected by a sensor (such as a limit switch), and the actual movement of the actuator is confirmed to advance the sequence. . Therefore, when the sensor fails, it is impossible to detect the limit of the actuator and the limit of return of the actuator, so that the sequence cannot be advanced and the operation of the device is stopped.
[0003]
For example, in a large facility used in an automobile factory, the number of actuators provided is also a considerable number, so the frequency of sensor failure increases. In the case of sequence control, only one sensor in the facility is used. Failures will result in equipment outages and will have a significant impact on productivity.
[0004]
In order to avoid this, conventionally, the facility operation rate is not lowered by changing the sequence program. In other words, when a failure of a certain sensor is confirmed, a sequence program for igniting the input condition of the sensor is created on the spot, and the equipment is temporarily turned on and forcibly operated. Then, after the operation of the facility is completed, the sensor is replaced and returned to the original sequence program.
[0005]
[Problems to be solved by the invention]
However, in such a conventional coping method, as shown in the flowchart of FIG. 6, when a sensor breaks down and the equipment stops (S1), a location (contact location) where the signal of the failed sensor is used. Is found in the sequence program (S2), the use point of this signal is deleted from the sequence program using the data editing device (S3), all use points are deleted (S4), and the equipment is restarted. Therefore, since the procedure of moving the line (S5) had to be performed, there was a problem that it took a lot of time to delete the signal use location.
[0006]
In particular, when the signal of a broken sensor is used at multiple locations, it will not be necessary to delete only the location where the signal is used, and it will be necessary to change the sequence program, so more time will be required. become.
[0007]
The present invention has been made in view of such a conventional problem, and is capable of forcibly stepping a sequence only by registering a failed sensor without changing a program. The purpose is to provide a device.
[0008]
[Means for Solving the Problems]
To achieve the above object, the present invention is configured as follows.
[0009]
The invention according to claim 1 is a set of exclusion command output means for outputting a failure sensor exclusion command, signal output condition storage means for storing a signal output condition for each sensor at the time of failure, and a set of sensor signal output conditions In the case where a step condition storage means for storing the step condition of the sequence configured as described above and an exclusion instruction for a failed sensor are output from the exclusion instruction output means, the step condition storage means stores the instruction. of stepping conditions, with subjecting an indication that there is excluded instruction stepping condition sensor corresponding to the exclusion instruction, by adding the signal output condition of the sensor corresponding to the exclusion instruction, a new increment And a step condition creating means for creating a condition.
[0010]
According to a second aspect of the present invention, in the sequence control device according to the first aspect, the sequence program storage means for storing a sequence program for operating the device, and the signal of the sensor connected to the input port in the normal state. The output state is compared with the step condition of the sequence stored in the step condition storage means, and if they match, one step of the sequence program stored in the sequence program storage means is executed, At the time of a sensor failure, the signal output state of the sensor connected to the input port is compared with a new step condition created by the step condition creating means, and when the step condition is satisfied, And control means for executing one step of the sequence program stored in the sequence program storage means. Characterized in that it has.
[0011]
According to a third aspect of the present invention, in the sequence control device according to the first or second aspect, the exclusion command output means is an editing device operated by an operator.
[0012]
According to a fourth aspect of the present invention, in the sequence control device according to the first or second aspect, the signal output condition for each sensor stored in the signal output condition storage means is the address and delay time of each sensor. It is comprised from these.
[0013]
【The invention's effect】
According to the sequence control device of the present invention configured as described above, the following effects can be obtained for each claim.
[0014]
In the invention described in claim 1 or claim 3, when a faulty sensor exclusion command is output, out of the stepping conditions, there is an exclusion command in the stepping condition of the sensor corresponding to the exclusion command. A new step condition is created by adding a signal output condition of the sensor corresponding to the exclusion command and creating a new step condition. This eliminates the need for program changes.
[0015]
In the invention according to claim 2 or claim 3, in the normal state, the signal output state of the sensor connected to the input port is compared with the step condition of the sequence. On the other hand, if a sensor failure occurs, the signal output state of the sensor connected to the input port is compared with the newly created step condition, and the step condition is satisfied. Since one step of the sequence program is executed, the sequence program advances according to the signal output state of the sensor connected to the input port in the normal state, while the new step created when the sensor fails. The sequence program advances according to the advance condition, and there is no need to change the program.
[0016]
In the invention according to claim 4, since the signal output condition for each sensor is composed of the address and delay time of each sensor, the signal output state of the sensors other than the failed sensor is sequenced when the sensor fails. After the delay time set for the failed sensor elapses, one step of the sequence program is executed after the delay condition is satisfied, and the forced sequence program step is automatically performed after the delay time elapses. Will be performed.
[0017]
DETAILED DESCRIPTION OF THE INVENTION
Next, an embodiment of a sequence control device of the present invention will be described in detail with reference to the drawings.
[0018]
FIG. 1 is a block diagram showing a schematic configuration of a sequence control apparatus of the present invention.
[0019]
As shown in the figure, the controller 10 is connected to a plurality of sensors 15 to 18 for detecting the operation limit of the actuator, and also connected to solenoids 21 to 23 and a motor 24. An editing device 30 is also connected for instructing the operator to exclude the failed sensor.
[0020]
The controller 10 has an input port 40 that connects the sensors 15 to 18, and an output port 50 that connects the solenoids 21 to 23 and the motor 24. Therefore, a signal output state is input via the input port 40, and the solenoid or motor is actually driven via the output port 50.
[0021]
The sequence program storage unit 60 stores an operation sequence of devices and facilities to be controlled as a ladder sequence program.
[0022]
The step condition storage unit 62 stores step conditions as shown in FIG. 2 for advancing the process step of the sequence program to the next process step. This step condition is configured as a set of sensor signal output conditions (sensor addresses and contact signals), and includes sensor addresses (port Nos.) And contact signals of all the sensors 15 to 18. The sensor address is the port number of the input port 40 to which the sensor is connected. In the case of FIG. 2, the sensor 15 is the port No1, the sensor 16 is the port No2, the sensor 17 is the port No3, It is assumed that 18 is connected to port No4. The contact signal means a signal output from the sensor, and is 1 when the signal is output, and 0 when the signal is not output.
[0023]
In the case of FIG. 2, the step condition necessary for stepping from step 1 to step 2 of the sequence program is that signals are output from the sensor 16 and the sensor 17. A step condition necessary for stepping is that signals are output from the sensor 17 and the sensor 18.
[0024]
The control unit 64 compares the signal output state (equivalent to the signal output condition) output from the input port 40 with the step condition stored in the step condition storage unit 62. The step sequence program is executed to drive the solenoids 21 to 23 or the motor 24 through the output port 50 as necessary.
[0025]
The signal condition storage unit 66 stores a signal output condition for each sensor at the time of failure, and the signal output condition includes an address of each sensor and a delay time as shown in FIG. In the example shown in the figure, when the sensor 15 fails, a delay time of 5 seconds, when the sensor 16 fails, a delay time of 3 seconds, when the sensor 17 fails, a delay time of 500 msec, When a failure occurs, a delay time of 1 sec is given.
[0026]
When the editing device 30 outputs a faulty sensor exclusion command, the step condition creation unit 68 extracts the signal output condition of the corresponding sensor stored in the signal condition storage unit 66 and the step condition storage unit. The signal output condition (part of the step condition) of the corresponding sensor is also taken out from 62, and a new step condition is created from both signal output conditions.
[0027]
The schematic configuration of the sequence control apparatus of the present invention is as described above. Next, the operation will be described in detail based on the flowcharts of FIG.
[0028]
FIG. 4 is a main flowchart of the sequence control apparatus of the present invention.
[0029]
When the sensor breaks down and the equipment stops (S11), the operator inputs the fact that the sensor is broken by the editing device 30. Based on the exclusion command output from the editing device 30, the step condition creation unit 68 takes out a macro command related to the failed sensor, such as the step condition shown in FIG. 2, from the step condition storage unit 62 (S12). The signal output condition of the failed sensor stored in the signal condition storage unit 66, for example, the signal output condition shown in FIG. 3 is extracted, and the step condition (registered in the macro instruction area) extracted from the step condition storage unit 62 is extracted. In addition to the signal output condition corresponding to the corresponding sensor, the signal output condition of the corresponding sensor extracted from the signal condition storage unit 66 is added (registered in the macro instruction exclusion area). ) To create a step condition including a pseudo new signal output condition. Then, the newly created step condition is stored in the step condition storage unit 62 (S13).
[0030]
For example, when the sensor 16 fails, when the operator inputs the fact that the sensor has failed with the editing device 30, the editing device 30 outputs an exclusion command for the sensor 16. This exclusion command is a command for excluding a signal output condition related to the sensor 16 among the running conditions. In response to this exclusion command, the step condition creation unit 68 takes out the signal output condition of the sensor 16 from the signal condition storage unit 66. Specifically, the signal output condition of [sensor address 2−delay time 3 sec] in FIG. (In the case of a step condition from step 1 to step 2 of the sequence program). Next, the stepping condition storage unit 62 takes out the increment condition of FIG. 2, further removed stepping condition of the sensor 16 of which, in particular in FIG. 3 [The sensor address 2 contact signal 1] ( from step 1 of stepping conditions to step 2) was taken out, macroinstructions are denoted by the display indicating that there is excluded instruction increment condition that [sensor address 2 contact signal 1] increment condition storage unit 62 At the same time, a signal output condition of [sensor address 2−delay time 3 sec] is registered in the exclusion macro instruction area of the step condition storage unit 62, and a new step condition combining both signal output conditions is registered. Create (S13).
[0031]
When the line cycle starts, the control unit 64 operates the device to be controlled in accordance with the step condition stored in the step condition storage unit 62 (S14).
[0032]
FIG. 5 is a subroutine flowchart showing the line cycle start process of S14 shown in FIG.
[0033]
When the line cycle is started, the control unit 64 takes out the sequence program stored in the sequence program storage unit 60 for one step, and any signal (0 or 1) from the sensor 15 to the sensor 18 via the input port 40. To see if is output. That is, the signal output state is observed. Then, the control unit 64 compares the step condition (see FIG. 2) stored in the step condition storage unit 62 with the signal output state input via the input port 40. As a result of this comparison, if the signal output state matches the step condition, the processing of that step is executed. For example, when the sequence program extracted from the sequence program storage unit 60 is step 2, the control unit 64 extracts the step condition from step 1 to step 2 from the step condition storage unit 62, and the input port 40. Compare with the signal output state input from. If the contact signals of the sensor addresses 1, 2, 3, 4 are 0, 1, 1, 0 as the input signal output state, the process of step 2 is executed (S21, S22).
[0034]
On the other hand, in the case of driving in which a sensor failure has occurred, the new step condition as described above is stored in the step condition storage unit 62. The control unit 64 takes out one sequence program stored in the sequence program storage unit 60 and looks at the signal output state via the input port 40. Then, the control unit 64 compares the step condition (see FIG. 2) stored in the step condition storage unit 62 with the signal output state input via the input port 40. If the signal output state does not match the step condition as a result of this comparison, an exclusion command is added to the step condition stored in the step condition storage unit 62 after a predetermined time has elapsed (S23). It is determined whether the signal output condition is included, and if the signal output condition with the exclusion instruction is included, the corresponding signal output condition is selected from the signal output conditions stored in the exclusion instruction area. Search and read the delay time (S24, S25).
[0035]
Then, after the delay time has elapsed, the process of the step is executed (S26). For example, when the sequence program extracted from the sequence program storage unit 60 is step 2, the control unit 64 extracts the step condition from step 1 to step 2 from the step condition storage unit 62, and the input port 40. Compare with the signal output state input from. For example, when the sensor 16 is out of order, if the contact signal of each of the sensor addresses 1, 2, 3, 4 is not 0, 1, 1, 0 as the input signal output state, for a certain period of time. After the elapse of time, the signal output condition for the sensor address 2 is searched. In this case, there is a signal output condition stored in the exclusion instruction area [sensor address 2−delay time 3 sec]. Will advance. That is, the process of step 2 is executed and the corresponding solenoid or motor is driven via the output port 50.
[0036]
Further, when there is no signal output condition corresponding to the exclusion command area of the step condition storage unit 62, the sequence cannot be stepped any further, so a new step condition is created (S27).
[0037]
As described above, in the sequence control device of the present invention, when the step condition is not satisfied, the signal output condition of the excluded macro instruction area is checked after a certain time has elapsed, and if there is a matching signal output condition, After the lapse of the registered time, the sequence is stepped on the assumption that the step condition is satisfied.
[0038]
Therefore, even when the sensor has failed, the forcible sequence program is automatically advanced, and there is no need to change the program. As a matter of course, the operation rate of the equipment is also improved as compared with the conventional one.
[Brief description of the drawings]
FIG. 1 is a block diagram showing a schematic configuration of a sequence control apparatus of the present invention.
FIG. 2 is a diagram illustrating an example of a step condition stored in a step condition storage unit.
FIG. 3 is a diagram illustrating an example of signal conditions stored in a signal condition storage unit.
FIG. 4 is a main flowchart of the sequence control device of the present invention.
FIG. 5 is a subroutine flowchart showing a line cycle start process in S14 shown in FIG. 4;
FIG. 6 is a flowchart showing processing of a conventional sequence control device.
[Explanation of symbols]
10 ... Controllers 15-18 ... Sensors,
21-23 ... Solenoid,
24 ... motor,
30 ... Editing device 40 ... Input port 50 ... Output port 60 ... Sequence program storage unit 62 ... Step condition storage unit 64 ... Control unit 66 ... Signal condition storage unit 68 ... Step condition creation unit

Claims (4)

Exclusion command output means for outputting a faulty sensor exclusion command;
Signal output condition storage means for storing signal output conditions for each sensor at the time of failure;
Step condition storage means for storing step conditions of a sequence configured as a set of sensor signal output conditions;
If the exclusion instruction sensor failed from the exclusion instruction output means is output, among the stepping condition stored in the increment condition storage unit, excluding the stepped condition of the sensor corresponding to the exclusion instruction A sequence control characterized by having a step condition creating means for creating a new step condition by adding a signal output condition of a sensor corresponding to the exclusion command and adding a display indicating that there is a command apparatus. Sequence program storage means for storing a sequence program for operating the apparatus;
When normal, the signal output state of the sensor connected to the input port is compared with the step condition of the sequence stored in the step condition storage means, and if it matches, it is stored in the sequence program storage means While one step of the sequence program being executed is executed, the signal output state of the sensor connected to the input port is compared with the new step condition created by the step condition creation means when the sensor fails. 2. The sequence control device according to claim 1, further comprising a control unit that executes one step of the sequence program stored in the sequence program storage unit when the step condition is satisfied. . The sequence control device according to claim 1, wherein the exclusion command output unit is an editing device operated by an operator. 3. The sequence control device according to claim 1, wherein the signal output condition for each sensor stored in the signal output condition storage unit is configured by an address and a delay time of each sensor.

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