JPH0659709A - Programmable controller - Google Patents

Abstract

(57) [Abstract] [Object] The present invention relates to a programmable controller that operates based on an SFC description, and realizes a programmable controller that enables reset-priority processing conforming to IEC in a relay set / reset command. The purpose is to [Configuration] When an action qualifier set to control the action corresponding to each action is a reset, the action qualifier sets an execution trajectory of the reset. When executing actions, first of all,
The action qualifier performs the action qualifier processing based on whether or not the reset execution locus is set, and then executes the actual action. When the action execution qualifier has a reset execution trajectory, the action bit of the corresponding action is not turned on.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention relates to SFC (Sequencial F
The present invention relates to a programmable controller that operates based on a unction chart) description, and more specifically, to a programmable controller that enables a reset-priority IEC-compliant processing in a reset command and a reset command.

[0002]

2. Description of the Related Art Conventionally, a programmable controller (hereinafter referred to as a PC) has been used for various physical quantity information at a work site (for example, a product which has passed through an exit of a belt conveyor has reached a predetermined quantity, that is, a receiving port). The transfer bucket etc. in is full), or logical information (for example, a sensor that scans the dangerous area detects a moving object when the cutting machine is operating). It can be programmed to perform predetermined output control (sequence control). Usually the progress of the process,
The on-site aspect such as work procedures is fluid. Therefore, the sequence control procedure at the work site is not such that the specifications are originally decided from the beginning, and it is possible to change or modify it according to the actual situation at the site, whether the PC is in trial operation or in actual operation. It is decided by repeating it constantly. Therefore, in order to easily deal with these changes, the PC has all the necessary control elements built-in, and a plurality of processing elements that combine the control elements to determine one output are preset. In the field, in many cases, a user program repeatedly selects and executes any one of the processes to perform sequence control.

The above description of the programming of the PC is intended from the beginning of the PC development so that people in the field, which were distant from the conventional hardware and software with respect to the computer, can easily construct a control program without resistance. , It usually involves a completely different form of description than computer programming. That is, the same one as the developed connection diagram (relay circuit diagram) by the symbol mark of the contact (limit switch) or coil (relay) used in the field before the PC is used. In the PC, the above-described program is translated into a machine language and becomes bit information in word units, which are sequentially written in a program storage memory such as a RAM in an address order.
The PC sequentially reads out the program in the order of addresses by an address counter that is counted by a clock signal, analyzes it by a decoder, reads corresponding data from a data memory based on the analyzed signal, and performs a logical operation. Iteratively determines one output signal. The output signal is written in the output data area of the data memory and then read by the output section to be an output signal for sequence control. That is, this becomes the same as the final output of the conventional relay circuit. Then, the PC repeats the above operation.

Further, as a program description method of a PC, a description format of an international standard (IEC SC65A / WG6) called SFC (Sequencial Functiont Chart) is known in recent years. FIG. 5A is a conceptual diagram of the structure of this SFC program description. As shown in the figure, in the program, a description section called STEP and a description section called TRANSITION are connected by a link, and S0, TN0,
S1, TN1, S2, ... Are arranged. PS
Determines that the subsequent step is not selected if the transition is on, and the subsequent step is not selected if the transition is off.

FIG. 2B shows a transition (TN0,
An example of the program description of TN1) and steps (S0, S1, S2) is shown. ON / OFF of each transition is the output value T of the result of the logical operation of each transition program.
It is determined by N0 and TN1. For example, if the output value TN0 of the transition (A) is on, the step (D) is selected, and if the output value TN1 of the transition (B) is off, the step (E) is not selected. Within one step, there are multiple actions (ACTION), and each action consists of a large number of instructions that perform a series of logical operations with one output or instruction word as a result.
Then, at the beginning of the action, an action qualifier (ACTION-QUALIFIERS) for instructing the execution timing of the action in the step is described. By this instruction, the selected action is executed and the unselected actions are not executed.

The above is a schematic description of the SFC description format. One of the instructions described in the SFC description format in the PC is the S (set) and R (reset) instructions of the relay. is there.

FIG. 6A shows an example of the S / R instruction of this relay. This operation is performed by setting A to Y000 as shown in FIG. 6B.
Is turned on and B is reset (ON), Y0
00 is turned off.

[0008]

Such a conventional PC
The S / R instruction in FIG.
As shown in (a) and (b), C first executes the R instruction (O
Even if N), if D later executes the S command (ON),
The post-execution S instruction is prioritized, and as a result, Y000 is turned on (the part (a) in the figure). When this is programmed by the SFC, it becomes as shown in FIG. In FIG.
There is an action (ACTION1 as the execution program name) in the step (process) S0, and its action qualifier (action execution control name, hereinafter AQ).
Is a reset (R). The meaning of AQ = R is to stop the execution of ACTION1 when S0 is active. Next is step S10, which is an action 1 similar to step S0.
, Its AQ is set (S), and ACTION
When 1 is executed, Y000 is unconditionally turned on. If this is considered in the same manner as the set / reset instruction, the post-execution has priority.

However, since reset priority is given to the IEC, there is a problem that the conventional method based on the set and reset instructions cannot comply with the IEC. In the present invention, the action qualifier (AQ) is reset (A
Set the execution locus when Q = R) and set all AQ
By executing all actions after executing, and always performing processing with priority on AQ = R,
The purpose is to enable reset priority processing in accordance with IEC.

[0010]

According to the present invention, for each action, AQ is reset (R), that is, AQ.
= R is set as the execution locus, and in the SFC execution process, the action execution process is divided into two parts, first the AQ process for all the actions, then the all To process the action of.

That is, when all AQ processing is performed, processing is performed for that action based on whether or not the execution locus of AQ = R is already set, and if the execution locus of AQ = R is set. , Do not execute the action.

[0012]

When the step to which AQ = R belongs is active, the execution locus of AQ = R indicates that a reset instruction has already been issued for the action of that step. This refers to whether or not the execution locus of AQ = R corresponding to the action is set before executing the action, and if the execution locus is set, it indicates that the reset instruction has already been issued. , In this case, do not execute the action for that action.

Therefore, the process in which AQ = R is always prioritized, and the process conforming to the IEC of reset priority can be performed.

[0014]

EXAMPLES Examples of the present invention will be described below. In this embodiment, an SFC program description as shown in FIG. 1 will be described as an example. Here, in order to explain the reset process priority, it is assumed that both steps S0 and S1 are active.

FIG. 2 is a flow chart showing the overall processing procedure based on SFC in the programmable controller. After the input process (process A1) by the input device, the transition condition is executed (process A2) and the previous step state and transition are performed. The migration process is performed according to the conditions (process A3).

In each of the processes A2 and A3, specifically, a transition condition (transition TN0 in FIG. 1) is turned on / off by turning on / off an input from a sensor or a switch by a program showing only the transition condition. If the input is on, TN0 is also turned on, and it is determined that the condition for shifting from step S0 to step S1 in FIG. 1 is satisfied. By a program that only shows the connection relationship of which step and which step is connected next, in this case,
If the transition condition TN0 is on, a process of transitioning from step S0 to step S1 is performed.

The transition processing is performed in this way, and in this case, it is confirmed that steps S0 and S1 are on (active), and the next processing, that is, the action of the step from the active state of the step, is performed. A process for controlling the bit is performed (process A4). In this process step S0
The AQ process (AQ = R) is performed according to the flow shown in FIG. In the figure, since step S0 is active here (process A11), the execution locus of AQ = R corresponding to ACTION1 is turned on (process A1).
2). Next, the action bit of ACTION1 in step S0 is originally off in this case, but is turned off regardless of it (process A13).

The above is the AQ process of step S0.
Next, the AQ process (AQ = S) in step S1 is performed as shown in FIG.
The flow is shown in (b). In this case, step S
1 is active (process A21), but since the execution locus of AQ = R is on at this time (process A22), the action bit corresponding to ACTION1 in step S1 is not turned on (process S23) and is turned off. The AQ process is terminated while the data is held at, and the process proceeds to the next AQ process.

After all the action qualifiers have been processed in this manner, then all the actions are executed (process A5 in FIG. 2). Then, the output device is controlled based on the action (process A6).

FIG. 4 shows a processing flow of the above-described action execution (processing A5 in FIG. 2). After the AQ processing is finished, the flow shown in FIG. 4 is entered. In this action execution flow, execution / non-execution of the action or reset processing is determined by turning on or off the action bit corresponding to the action number. That is, in the process flow of FIG. 4, it is determined whether the action bit corresponding to the action number to be executed is on (process A31), and if it is on, the action is executed (process A32). If the action bit is off, it is determined whether it was on or off in the previous scan state (process A33), and if it is on in the previous scan state, the action is reset (process A34).

In the case of this embodiment, each step S0, S1
Since the action bit of ACTION1 in 1 is not turned on, Y000 shown in FIG. 1 remains held in the off state, and AQ of SFC can be reset priority. In this way, the reset priority process can be performed by performing the processes according to the process flows of FIGS. 2 and 3. The execution trace of AQ = R needs to be cleared at the end of calculation or the start of calculation of one scan (process A1 to process A6 in FIG. 2).

[0022]

According to the present invention, the execution locus is set when the action qualifier that controls the action is reset (AQ = R), and the execution locus is turned on when AQ = R is executed. In addition, by executing all actions after executing AQ in all steps, the execution locus of AQ = R is always checked even when AQ = S (set) is executed, so that AQ = The processing in which R is prioritized can be performed, and the control according to the IEC of reset priority can be performed.

[Brief description of drawings]

FIG. 1 is a diagram showing an example of SFC description for explaining an embodiment of the present invention.

FIG. 2 is a flowchart illustrating an overall processing procedure of SFC description in a PC.

FIG. 3 is a flowchart illustrating a processing procedure based on the content of an action qualifier.

FIG. 4 is a flowchart illustrating an action execution procedure.

FIG. 5 is a diagram illustrating an SFC description of a conventional PC.

FIG. 6 is a diagram illustrating a set / reset instruction in a conventional PC.

FIG. 7 is a diagram illustrating post-execution priority processing in a set / reset instruction in a conventional PC.

8 is a diagram for explaining the post-execution priority process shown in FIG. 7 with an SFC description.

[Explanation of symbols]

 S0, S1 step AQ action qualifier S set instruction R reset instruction

Claims (1)

[Claims] 1. SFC (Sequencial Functiont Chart)
In a programmable controller that operates by setting execution or non-execution of an action based on the description, when the action qualifier set to control the action corresponding to each action is reset, the action qualifier While setting the reset execution trajectory, the action qualifier is first processed for all actions, then all actions are executed, and the action qualifier performs the reset execution trajectory. The programmable controller is characterized in that, when is set, the action bit of the corresponding action is held in the off state.