JPH07120176B2 - Programmable controller - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Field of Industrial Application) The present invention relates to a programmable controller that is used by being integrally incorporated in an NC device.

(Prior Art) In a programmable controller used by being incorporated in an NC device, a predetermined signal is transmitted and received between the main control unit of the NC device and an input / output device connected to an external device. Executes a large number of sequences cyclically. The external devices are sensors such as an emergency stop button, an overtravel detection switch, a home position return limit switch, actuators such as various solenoids and various lamps.

In a conventional programmable controller, sequential addresses are added to a large number of sequences, and the sequences are sequentially executed from a start address to an end address.

In this case, for example, the execution time of the unit sequence is 10μ
If s and the number of sequences (steps) are 900, the cycle time is 9 ms.

(Problems to be Solved by the Invention) However, the conventional programmable controller as described above has a configuration in which a large number of sequences are sequentially and cyclically executed. There was a problem that the speed was delayed.

For example, in the example in which the number of sequences is 900, the emergency stop has a maximum delay of 9 ms. Further, in the origin return limit switch, a stop error occurs due to a delay in processing speed.

Therefore, it is an object of the present invention to speed up the processing speed of a sequence having an emergency in a programmable controller integrated in an NC device.

[Structure of the Invention] (Means for Solving the Problems) The present invention for solving the above problems is to provide a predetermined signal between an input / output device connected to a main control unit of an NC device and an external device. In a programmable controller that cyclically executes a large number of sequences while transmitting and receiving, the large number of sequences are divided into an emergency sequence group that requires an emergency and a plurality of normal sequence groups that do not require an emergency to form a group, and The feature is that the entire sequence is cyclically executed while interposing the emergency sequence group between each normal sequence group.

(Operation) In the present invention, since an urgent sequence group is inserted between each of a plurality of normal sequence groups, the number of groups is n, the number of sequences of each group is m, and it is necessary to execute a unit sequence. If the time is Δt, the processing cycle time of the urgent group is Ct, and the cycle time of the entire sequence is C ^T , then Ct = 2 · m · Δt (1) C ^T = 2 · (n−1) m · ΔT (2) In this case, the processing speed of the urgent sequence is S = n / 2 (3) times faster than the conventional one.

(Examples) Examples of the present invention will be described below with reference to the accompanying drawings.

FIG. 1 is a block diagram showing the positioning of a programmable controller (hereinafter abbreviated as PC) with respect to the NC device.

As shown in the figure, the PC 1 is connected to the main software 5 of the NC device 3 and is also connected to the machine 7 via Di (digital input) 9 and Do (digital output) 11. The machine 7 is, specifically, an emergency stop button,
It is subdivided into sensors such as overtravel detection switches and home return limit switches, and actuators such as solenoids and lamps.

The PC 1 has a CPU 13 and a memory (ROM and RAM) 15 built therein.

The memory 15 includes a controller program (sequence) area 15a, a bit expansion RAM area 15b, a communication area 15c, and a D area, as shown in the memory map in FIG.
It is divided into an i / Do area 15d, a memory mapped I / O area 15e, and the like.

In the PC having the above configuration, when the NC device 3 is powered on, the main software 5 activates the PC1, the PC1 enters a loop state, and the sequence program is periodically executed.

FIG. 3 is a ladder diagram of a sequence applied in this example.

As shown in the figure, the sequence of this example is divided into an emergency sequence group G1 that requires an emergency and eight normal sequence groups G2 to G9 that do not require an emergency. The number of steps in the sequence of each group is 100. The time required to execute each step is 100 μs.

FIG. 4 is a time chart of the execution cycle, and FIG. 5 is a flowchart showing the contents of processing.

As shown in FIG. 5, in this example, after the initial processing is performed in step 501, the emergency sequence group G1 is executed in step 502, and the next normal sequence group G2 to G9 executed previously in steps 503 to 508. To execute.

Therefore, in this example, as shown in FIG. 4, since the emergency sequence group G1 is executed by being interposed between the normal sequence groups G2 to G8, the emergency sequence group G1 is executed once in a unit of 2 ms and the entire normal sequence G2 is executed. ~ G9 is executed and then the emergency sequence group G1 is executed, while the processing speed is 4.
5 times faster.

In other words, in the past, a maximum delay of 9 ms occurred during an emergency stop, but this delay can be reduced by 4.5 times. Also, while there was a maximum delay of 9 ms in stop control after the home return limit switch signal was output, this can be suppressed to a maximum of 2 ms,
The stop position can be made so accurate.

On the other hand, the normal sequence groups G2 to 8 are conventionally executed in a cycle of 9 ms, but this is 18 ms, but since these sequences are lamps that do not require emergency, there is no delay of this extent. There is no obstacle.

In the above embodiment, the number of sequences in each group is the same, but this number does not necessarily have to be the same.

Further, in the above embodiment, an example in which the number of emergency sequence groups is singular is shown, but the number of emergency groups is plural according to the degree of urgency, and for example, these groups are normally skipped between each normal sequence group. You may make it interpose between sequence groups.

The present invention is not limited to the above embodiment, but can be implemented in other modes by making appropriate design changes.

[Effects of the Invention] As described above, the present invention divides a processing sequence into an emergency sequence group that requires an emergency and a plurality of normal sequence groups that do not require an emergency, and forms a group. Since this is a programmable controller that cyclically executes all sequences while intervening between them, it is possible to quickly execute urgent sequences according to the number of groups, and detect emergency stop, home return signal detection, and overtravel. You can quickly perform urgent processing such as position detection,
The performance of the NC device can be improved accordingly.

[Brief description of drawings]

FIG. 1 is a block diagram showing the positioning of the programmable controller in the NC device, FIG. 2 is a memory map of the programmable controller, FIG. 3 is a ladder diagram of the sequence applied in this example, and FIG. 4 is the execution cycle time. The chart and FIG. 5 are flowcharts showing the contents of the processing. In the drawing, 1 is a programmable controller, 3 is an NC device, 5 is main software, 7 is a machine, 9 is a digital input, 11 is a digital output, 13 is a CPU, and 15 is a memory.

Claims (1)

[Claims] 1. A programmable controller which is connected to a main control section of an NC device and an external device and cyclically executes a large number of sequences while exchanging predetermined signals with an input / output device. The sequence is divided into an urgent sequence group that requires urgency and a plurality of normal sequence groups that do not require urgency to form a group,
A programmable controller which cyclically executes all sequences while interposing the emergency sequence group between each normal sequence group.