JPH0630004B2 - Counter preset method in programmable controller - Google Patents

Description

The present invention relates to a programmable controller typified by a ladder diagram type, and in particular, in a unit provided with a counter instruction processing means operating in a down-count type, initial setting (preset) of the counter function thereof. Of technology.

As is well known, the counter instruction of the programmable controller emits the output specified by the counter command when the input count of the input / output signal specified by the counter command is counted by the set value specified by the counter command. It is a thing.

The processing for realizing the above counter instruction is performed by presetting the set value of the counter instruction in the user program in a predetermined number area of the counter memory in response to a preset signal (set by the user program), and then the preset value In general, the data processing of the down-count method in which a count input signal (set by the user program) is sequentially subtracted and an output is issued when the data becomes 0 is common. . This method is advantageous for each stage in speeding up data processing.

Also, in most programmable controllers, the counter function is designed to be power failure compensated. That is, the above-mentioned counter memory is made non-volatile, and its value is retained even if a power failure occurs, and the counting operation that continues from before the power failure is performed. In addition,
The term "power outage" includes the case where the power switch of the device is turned off.

A very general programmable device configured as above
When the user adds a new counter command in the controller, the set value of the counter command must be preset in the counter memory.

Conventionally, as a preset method in such a case, first, there is a method of operating the key input device of the program console to access the counter memory one by one and write it. However, in such a method, it is necessary for the user to manually perform presetting each time.

There is also a method in which a preset circuit is set in the user program in association with each counter instruction (on the program), and a special preset circuit is provided in the user program when a new counter instruction is added. However, also in this case, there is a trouble that a special preset circuit must be newly provided.

The present invention has been made in view of the above-described conventional problems, and an object thereof is to perform a troublesome operation of manually presetting a counter command when a new counter command is added to a user program. Another object of the present invention is to provide a counter preset method in a programmable controller that allows the preset value to be automatically preset in the counter memory without providing a special preset circuit in the user program.

To achieve the above object, the present invention executes a user program in a programmable controller including a counter instruction processing unit that operates in a down-counting manner and a counter memory that stores counter data is non-volatile. It is characterized by including the following respective means that operate before.

A: means for retrieving counter numbers used in the user program, B ... first clear all used flags set in the counter memory corresponding to each counter number, and detected by means A Means for setting the used flag corresponding to the counter number to "1", C ... Corresponding to the counter number detected by the means A, among the preset flags set in the counter memory corresponding to the respective counter numbers. Means for checking whether the number is "1" or "0", D ... When the means C detects "1", the preset value of the counter instruction of the corresponding number is preset in the corresponding number area of the counter memory. And the means for setting the preset flag of the corresponding number to "0", E ... The remaining counts other than the used counter number detected by the means A Means for setting the corresponding preset flag to "1" for the data number.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

FIG. 1 is a block diagram showing an overall schematic configuration of a programmable controller to which the present invention is applied. This programmable controller includes a CPU 1 which is the center of overall control, a ROM 2 which stores a system program executed by the CPU 1, a RAM 3 which is used as a system working memory by the CPU 1, and a sequence control program which is arbitrarily set by a user. , A user program memory 4 in which is stored, an input circuit 5 serving as an input interface to which an external input signal is applied, an output circuit 6 serving as an output interface for sending an external output signal, and various operation commands to the CPU 1 and the user. A program console 7 used for creating and inputting a program is provided.

The RAM 3 is provided with an input / output memory 31 serving as a buffer memory corresponding to each input / output signal of the input circuit 5 and the output circuit 6 in a one-to-one manner. A counter memory 32 for storing current value data is set. The counter memory 32 is non-volatile. FIG. 2 shows the configuration of the storage area of the counter memory 32. This memory 3
2 is each number C1 of a plurality of preset counters
In addition to having data areas corresponding to C2, C3, ..., In order to apply the present invention, a preset flag P and a used flag U are set corresponding to each counter number.

FIG. 3 is a flow chart showing the outline of the system program executed by the CPU 1 centering on the essential part of the present invention. This will be described below according to this flowchart.

When the controller is powered on, a predetermined initialization is executed, and then the state of the mode key of the program console 7 is determined in step 100.
If the mode key indicates that the program is being executed, the user program is executed once in step 101, and in the next step 102, other system processing such as input reception and display of the program console 7 is performed, and the first step 10
Return to 0. The above operation is repeated during the program execution.

When the mode key indicates a mode other than the execution of the user program, the process first proceeds to step 103, and all the used flags U1, U2, U in the counter memory 30.
Clear 3, ... to “0”. Next, in step 104, the user program is sequentially read one instruction at a time, and step 1
At 05, it is determined whether the user instruction is a counter instruction. When the counter command is detected, it is judged at step 106 whether or not the preset flag P corresponding to the counter command number is "1". At this time, the preset flag P
"0" means that the set value for the counter number has already been preset in the counter memory 32. The fact that the preset flag P is "1" means that the set value for the counter of that counter number has not yet been preset in the counter memory 32. In that case, the set value in the user program is preset in the data area of the counter memory 32 of the corresponding number in step 107, and then the preset flag of the corresponding number is set to "0" in step 108. Step 10 above
When NO is determined in step 6 and after step 108 is executed, the use flag U of the corresponding counter number is set to "1" in step 109. This step 10
After execution of step 9 and if it is determined in step 105 that the counter is not the counter, it is determined in the next step 110 whether or not the check has been completed up to the end of the user program. The above operation is repeated for the instruction. When the processing is completed up to the end of the user program, the process proceeds to step 11,
For a counter number for which the used flag U in the counter memory 32 is "0", the preset flag P corresponding thereto is set to "1". Then step 10
Go to 2.

By the above processing, the counter memory 32 which is used for the first time (its corresponding preset flag P is “1”) is automatically preset with the set value in the counter memory 32, and the preset flag is set to “0”. As a result, it is recorded and held that the preset has been completed. Further, a counter which is not used in the original user program and which is newly used by the additional change of the user program is detected by checking the used flag U.

The counter preset processing from steps 103 to 111 is performed in an operation mode other than the user program execution mode in the above embodiment, but the present invention is not limited to this. Without
It is the same if the mode is switched to the program execution mode and configured to do this before executing the user program.

As described in detail above, according to the counter preset method in the programmable controller according to the present invention, when a new counter instruction is added to the user program, the set value is automatically preset in the counter memory. Therefore, it is not necessary for the user to manually perform presetting, and it is not necessary to provide a special preset circuit in the user program. As a result, the count-up state immediately after the start of the operation is eliminated, and an additional reset circuit associated with the counter is not added during programming, so that the restrictions on the user program design are reduced and the user program capacity can be reduced. Connect

[Brief description of drawings]

FIG. 1 is a block diagram showing a schematic configuration of a programmable controller to which the present invention is applied, FIG. 2 is an explanatory diagram showing a data configuration of a counter memory, and FIG. 3 is an outline of a system program executed by a CPU. 3 is a flowchart showing mainly the part that is the gist of. 1 ... CPU 3 ... RAM 31 ... Input / output memory 32 ... Counter memory 4 ... User program memory C1, C2, C3, ... Counter number P1, P2, P3 ... Preset flag U1, U2, U3 ... Used flag

Claims (1)

[Claims] 1. A programmable controller comprising a counter instruction processing unit that operates in a down-counting manner, and a counter memory that stores counter data is non-volatile. The following units operate before execution of a user program. Programmable characterized by having
Counter preset method in the controller. A: means for retrieving counter numbers used in the user program, B ... first clear all used flags set in the counter memory corresponding to each counter number, and detected by means A Means for setting the used flag corresponding to the counter number to "1", C ... Corresponding to the counter number detected by the means A, among the preset flags set in the counter memory corresponding to the respective counter numbers. Means for checking whether the number is "1" or "0", D ... When the means C detects "1", the preset value of the counter instruction of the corresponding number is preset in the corresponding number area of the counter memory. And the means for setting the preset flag of the corresponding number to "0", E ... The remaining counts other than the used counter number detected by the means A Means for setting the corresponding preset flag to "1" for the data number.