JPH02275503A - Programmable logic controller - Google Patents

Abstract

PURPOSE:To rapidly restart an interrupted sequence by driving all switches corresponding to executed steps and indicating the step to be executed next by the head of undriven switches. CONSTITUTION:The switches 10-1 to 10N are connected in series and respectively driven by executing their corresponding steps 1 to N. Namely, sequence control processing using a RAM 22 is executed by an MPU 24 in accordance with the contents of a ROM 20. Various sensors (e.g. a sensor for generating an alarm signal at the time of detecting a fault is also included) and actuators (e.g. an electromagnetic valve of a cylinder) are connected to an I/O interface 26 and the sequence of respective actuators are controlled in accordance with the outputs of those sensors. Consequently, a fault can be restored within a short time and sequence control can be rapidly restarted from its interrupted state.

Description

[Detailed Description of the Invention] [Summary] The present invention relates to a programmable logic controller in which processing of each step is sequentially executed, and the purpose of the present invention is to provide a programmable logic controller that can quickly restart an interrupted sequence. In the controller,
It is constructed by connecting a plurality of switches in series, each of which is driven by the execution of a corresponding step.

[Industrial Application Field] The present invention relates to a programmable logic controller in which processing of each step is executed sequentially.

Programmable logic controllers are widely used to automate various processes on assembly lines and manufacturing lines.

[Prior Art] In a controller, such as a ladder type programmable logic controller, in which processing of each step is executed sequentially, a counter indicating a step to be processed is reset by an alarm signal indicating the occurrence of a failure. Sequence is interrupted.

[Invention tries to solve! ! In conventional programmable logic controllers, the counter indicating the steps to be processed is reset when a fault occurs, so the sequence is started from the beginning when operation is resumed after the fault is recovered.

Therefore, if it is desired to continue the sequence from an interrupted state, it is necessary to set the value of the above-mentioned counter to indicate the next step.
It took a long time to restart the sequence.

The present invention has been made in view of the above-mentioned conventional problems,
The aim is to provide a programmable logic controller that allows to quickly resume interrupted sequences.

[Means for Solving the Problems] In order to achieve the above object, a controller according to the present invention is configured as shown in FIG.

In FIG. 1, switches 10-1, 10-2...1
0-N are connected in series, and the corresponding steps 1.
2...N are each driven.

[Operation] In the present invention, all the switches corresponding to the executed step are activated, so that the first unactivated switch indicates the next step to be executed.

[Embodiments] Hereinafter, preferred embodiments of the controller according to the present invention will be described based on the drawings.

FIG. 2 shows the configuration of the embodiment, in which sequence control processing using the RAM 22 is performed in the MPU 24 according to the contents of the ROM 20.

The human output interface 26 is equipped with various sensors (
(including those that generate an alarm signal when a fault is detected) and actuators (for example, a solenoid valve of a cylinder) are connected, and each actuator is sequence-controlled according to the output of these sensors.

The ladder diagram in FIG. 3 explains the processing contents of the MPU 24, and the number 8? ? (??=01.02.03--
#15), the input/output relay has the code M? ? (??:
00. I! IL20...30.31) causes the internal relay to switch to code S? ,? ? (?, ??=1..00.
1.0! , 1.02. 1.03...1.23
．． 1.24. 1.25? Koyori Sequence Station・
Tsuburi Relay.

Code T? ? (77:18.19.20- ・-30,
31) Timers are shown from d to d.

In the circuit showing the first sequence step in the same area, pickpocket, -Sl, 00 (7) Koi) L, Nirei 51.0! .

Sl, 02. Sl, 03... Sl, 23. Sl,
24.51.25 normally closed contacts are connected in series.

And relay 51.01. Sl, 02. Sl, 0
3...Sl.

The normally closed contact of relay 815 is connected in parallel to the normally closed contact of 23, Sl, 24.51.25, and the contact is closed when the sequence is reset.

Therefore, the coils of relays st and oo are forcibly energized when the sequence is reset.

In the circuit showing the next sequence step, the relay contact of relay MOO, the relay contact of relay 801, and the normally closed contact of relay 803 are connected in series to relay 51.01, and the normally closed contact of relay MOO is The normally closed contact of relay 801 is closed when the sequence control activation condition is satisfied, and the normally closed contact of relay 803 is closed when sequence control is interrupted.

As a result, relays S+ and Ot are energized when sequence control is activated, and de-energized when sequence control is interrupted.

Furthermore, in each circuit representing subsequent sequence steps, relays S1.01. Sl, 02.51.03・
...51.23. Sl, 24. Sl, 25 coils are inserted in order.

Therefore, when the processing of these sequence steps is performed in order, relays 51.0+, Sl, 02. Sl, 0
3...-51, 23, 5+, 24.51.25 (7) When the power is turned on to a controller whose normally closed contacts are successively open or higher, relay 51.0 is activated in the first sequence step.
+, 51.02°Sl, 03...51.23. S
l, 24.51.25 normally closed contacts are closed, relay 5
1.00 coil is energized.

In the next sequence step, the normally closed contact of relay MOO is closed due to the fulfillment of the activation condition of the sequence control, and at that time, when the normally closed contact of internal relay 801 is closed, relay S1. The coil of Ol is energized and sequence control is activated.

When the coil of relay 51.01 is energized in this sequence step, the normally closed contacts of relay Sl, 01 are closed in the roughly next sequence step, so that
The normally closed contacts of relay 51.1.01 are opened and the normally closed contacts of relay 51.
02 coil is energized.

Also, in the next sequence step, relay 51.0
2 coil energization closes its normally closed contacts, resulting in
The normally closed contacts of relay S1.02 are closed and the coil of relay 51.03 is energized.

Thereafter, each relay coil is energized in turn in the same way. For example, when the coil of relay 51.12 is energized,
Relay S1 in the previous step sequence. O
1, 5+, 02.51.03...Sl, 11 normally closed contacts are all opened.

At this time, if a fault occurs and the normally closed contact 803 of relay BO3 is opened manually by the alarm shield, relay S! , 12 coils remain energized, timer T19
When the time-up occurs and the normally closed contact closes, sequence control is interrupted and the controller stops.

At this time, the administrator determines whether sequence control should be performed from the beginning or whether it should be continued from the interrupted state.

If it is determined that sequence control should be performed from the beginning, the normally closed contact 815 in the first step sequence is opened.

This causes relay S1. The coil of OO is energized and the sequence control starts again from the beginning.

Further, when it is determined that sequence control should be continued from the interrupted state, relay 51.01.
Sl, 02. 51.03・・・Sl, 23.
Sl, 24. The first one (relay S+, 13) whose normally closed contact is closed among Sl, 25 is checked, and the conditions for energizing the coil of this relay (51, 13) are established.

That is, internal relay M20 is driven and normally closed contact 802 for starting is connected.

As a result, the coil of relay 51.13 is energized, and sequence control is continued and performed from this interrupted state.

In FIGS. 4, 5, and 6, sequence control of a controller applied to a printed circuit board function tester is explained using a ladder diagram.

In these 4th ward, Figures 5 and 6, the number 3 is
'>7 (??=01...), the contact (of the human output relay) has a code of M? ? (??=OO...) causes the internal relay to switch to code 7':+7 (')')=:IQ
), the timer is set to the code S? ,? ? (?,??
:1.00...) indicates the relays of each sequence step.

Contact 815 is used to reset sequence control, contact 832 is used as a manual motor switch, contact 801 is used to start sequence control,
Contact 803 is used for sequence floating.

Note that this functional testing machine performs sequence control of the cylinders, and when a failure occurs during the control, it is required to immediately stop each cylinder.

It is also required to continue sequence control from that state as necessary.

In the sequence control shown in Figure 'is4, Figure 5, Figure 6, relays S+, 01
．． Sl, 02. Sl, 03◆-・51.23. S
The coils L, 24, 51, and 25 are energized in order, and the front normally closed contacts are opened one after another.

Then relay 51.01.51.02. Sl, 03
...St.

When all the coils 23, 5+, 24, 51, and 25 are energized, one sequence control is successfully completed.

Here, when the sequence control is interrupted by an alarm signal due to the occurrence of a failure and the controller is stopped, the administrator determines whether to perform the sequence control from the beginning or continue from the interrupted state.

At that time, if it is determined that sequence control should be performed from the beginning, contact 832 is operated to switch to manual mode, and then contact 815 is closed.

This energizes the coils of relays st and oo again,
Sequence $III is started from the beginning.

Further, when it is determined that sequence control should be continued from the interrupted state, relay 81.01.
Sl, 02.51.03- ・-51,23, sl, 2
4. The first of Sl, 25 whose normally closed contacts are closed (for example relay 51.13) is checked and, after the fault recovery work, conditions are established for energizing the coil of this relay (Sl, +3).

As a result, the relay coil in the next sequence step is energized and sequence control is restarted from that state.

As explained above, according to this embodiment, a plurality of normally closed contacts, each of which is opened by the execution of a corresponding sequence step, are connected in series, and the first closed contact, which remains closed, is Since the correct sequence step can be confirmed, it is possible to recover from a failure within a short period of time and quickly resume sequence control from an interrupted state.

[Effects of the Invention] As explained above, according to the present invention, a plurality of switches each driven by the execution of a corresponding sequence step are connected in series, so the first switch that is not driven is used to control the next execution. The correct sequence step can be confirmed, and therefore, it is possible to recover from a failure within a short period of time and quickly resume sequence control from the interrupted state.

[Brief explanation of drawings]

Fig. 1 is a diagram explaining the principle of the invention, Fig. 2 is an illustration of the groove bottom of the embodiment, Fig. 3 is a ladder diagram explaining the basic operation of the embodiment, Figs. 4, 5, and 6. is a ladder diagram explaining a more specific effect of the implementation sequence. 20 φ ・ ・ ROM 22 --- RAM 24 ◆ ・ ・ MPU 26...Person output interface 801, 8 (12,803, old 5.MOO, M2O・
・・Contact S1.00.51.0+, SL, 02.51
．． 03・Φ Bow 1.23.5+, 24. Sl, 25...
・Relay TI9...Timer Figure 1

Claims (1)

[Claims] In a programmable logic controller in which processing of each step is sequentially executed, a plurality of switches (10-1, 10-2) each driven by execution of a corresponding step (1, 2...N) are provided. ...10
-N) connected in series.