JPH0387902A - Output abnormality detecting device for sequence controller parallel operation device - Google Patents

Abstract

PURPOSE:To warn an external output part of the occurrence of abnormality by outputting an output abnormality detection signal after deciding the occurrence of abnormality of an external output part when the discordance is detected between the OFF command value supplied to a load and the current conversion value obtained in an output state of the load side. CONSTITUTION:An OFF relay number arithmetic part 14 operates the number of relays kept OFF based on the input current value and supplies this operated result to a comparison/decision part 16. At the same time, an ON/OFF command value arithmetic part 13 always operates the ON/OFF command values outputted from the ON/OFF command output parts 11 and 12 and supplies these operated results to the part 16. The part 16 compares the bit value of an OFF command with the operated number of OFF relays. If no coincidence is obtained from the comparison, it is decided that the abnormality occurred at the final output stage of an external output part 5 (6). Then an output abnormality detection signal is outputted to a warning output part 7 via an output abnormality detection signal output part 17. Thus it is possible to quickly detect such an abnormal state where the output cannot be turned off owing to the trouble of the external output part.

Description

Detailed Description of the Invention [Objective of the Invention] (Industrial Field of Application) The present invention provides an output abnormality that can promptly detect an output abnormality of an external output section of a sequence controller in a sequence controller parallel operation device. Regarding a detection device.

(Prior Art) In recent years, for example, in oil refining plants, thermal power plants, etc., sequence controller parallel operation devices have been used that operate duplex sequence controllers.

FIG. 4 is a configuration diagram showing an example of this type of sequence controller parallel operation device.

In FIG. 4, two sequence controllers 100
, 101 are operated in parallel according to the same program, and their chassis each house an external output board in which external output units 102 and 103 are incorporated.

The outputs of the sequence controller main bodies 100 and 101 are respectively output in parallel from external output units 102 and 103 to a relay 104 that is a controlled object.

That is, in such a sequence controller parallel operation device, from the relay 104 side, even if the output of one sequence controller main body 100 is turned off due to a failure or maintenance, the other sequence controller main body 101 will not operate normally. If the output is on, the relay 104 can continue operating normally, although parallel operation is no longer possible.

(Problem to be Solved by the Invention) However, in such a sequence controller parallel operation device, one of the sequence controller main bodies 100 may be unable to output normally due to a failure of its external output section 102, for example, an output transistor. If the state is such that it cannot be turned off when it should be turned off, even if the output of the other normal sequence controller main body 101 is turned off, the relay 1
There was a problem in that the output for 04 could not be turned off, making it impossible to continue normal operation.

An object of the present invention is to provide an output abnormality detection device for a sequence controller parallel operation device that can promptly detect an abnormality in which the output cannot be turned off due to a failure in the external output section, which is the final output stage. It's about doing.

[Structure of the Invention] (Means for resolving the problem) In order to achieve the above object, the present invention provides a sequence controller parallel operation device that is operated in parallel by the same program and outputs an on/off command to a load via an external output section. means for converting the output state of the load side into a current, means for comparing the OFF command value supplied to the load with the current conversion value of the output state of the load side at this time, and the OFF command value. and means for determining that the external output section is abnormal and outputting an output abnormality detection signal when the current conversion value and the current conversion value do not match.

(Function) Each sequence controller is operated in parallel by the same program to control the load on and off.

If an abnormality occurs in the external output section, which is the final output stage, and the load cannot be turned off even though an off command is output, the present invention detects the output state of the load side by converting it into a current, The converted current value and the off command value are compared. Then, when the two are different, an output abnormality detection signal is output.

This provides a warning that an abnormality has occurred in the external output section, improving the reliability of the system.

(Embodiment) FIG. 1 is a configuration diagram of an embodiment of an output abnormality detection device for a sequence controller parallel operation device according to the present invention.

As shown in the figure, the two sequence controller bodies 1.2 are operated in parallel by the same control program.
External output section 5, which is individually incorporated into external output board 3.4,
6 to control relays Xi to X16, which are loads.

The external output sections 5 and 6 each include 16 output transistors T1 to T16 and T17 to T, as shown in FIG.
32, and supply each collector output to the corresponding relays X1 to X16 for parallel control. Each of the relays X1 to X16 includes an a contact (normally open contact) that turns the load on and off, and an auxiliary contact (normally closed contact) used to calculate the number of off relays, which will be described later.

In addition to the external output section 5, the external output board 3 of this embodiment has an alarm output section 7 equipped with an output transistor T built-in, and is turned on when an output abnormality signal is supplied from the sequence controller main body 1. Then, an alarm command is output to the alarm device 8 consisting of an alarm, a warning lamp, etc. to sound an alarm or turn on a warning lamp.

Furthermore, in this embodiment, an external analog current input section and
The off-relay detection circuit 10 is also provided.

As shown in FIG. 3, the off-relay detection circuit 10 connects resistors R1 to R16 in parallel to the auxiliary contacts (normally closed contacts) of the relays X1 to X16, and detects the current supplied from the DC power source E, that is, The current conversion value of the off-relay is supplied to the external analog current input section 9.

As shown in FIG. 3, the external analog current input section 9 includes a limiting resistor RO, and its maximum value is limited so that an excessive current is not input when all relays X1 to X16 are on. The manually inputted current is digitized and then output to the sequence controller main body 1.

The sequence controller main body 1 has external output sections 5 and 6.
On/off command output section 11
and an on-off command value calculation that takes in the on-command and off-command output from the on-off command output section 11 and the on-command and off-command output from the on-off command output section 12 of the sequence controller 2 and calculates the command value. Part 13
and the current value input section 1 via the external analog current input section 9.
5, an off-relay number calculation unit 14 that calculates the number of off-relays from the manually input current value; a comparison and determination unit 16 that compares the calculated number of off-relays with the off command value; The output abnormality detection signal output section 17 outputs an output abnormality detection signal to the alarm output section 7 when it is determined that the command value is different from the command value.

Next, the operation of this embodiment configured as described above will be explained.

On/off command output section 1 of sequence controller main body 1
When an ON command is output from 1 and 1 of the external output section 5, for example, the output transistor T1, is turned on, the relay X1 connected thereto is turned on. The sequence controller main body 1 and the sequence controller main body 2 are operated in parallel by the same program, so if the sequence controller main body 1゜2 and the external output parts 5 and 6 are functioning normally, the sequence controller main body An on command is output from the on/off command output section 12 of No. 2, and the output transistor T17 of the external output section 6 is also turned on.

At this time, even though the sequence controller main body 2 issues an ON command to the transistor T17,
Even when the transistor T17 cannot be turned on, since the sequence controller bodies 1 and 2 are connected in parallel, the relay X1 is turned on and normal operation is possible.

However, even though transistors T1 and T17 are commanded to turn off, when they cannot be turned off due to a failure of transistor (4B), relay You will not be able to drive properly. In order to detect this state, the off-relay detection circuit 10 shown in FIG. 2 operates as follows.

If the resistance values of the resistors R1, R2...R16 connected in parallel to the auxiliary contacts of each relay X1 to X16 are set to the same value R, for example, when only relay X1 is off, the voltage
Then, the current ■ flowing to the external analog current input section 15 is 1-E/(R2+◆...+R16+RO)-E/ (1
5*R+RO).

Also, if all relays Xi, X2, . . . X16 are off, 1-E/RO occurs. Therefore, the current I is proportional to the number of relays that are turned off.

After the current l is digitized by the external analog current input section 9, it is supplied to the off-relay number calculation section 14 via the current value input section 15.

The number of off-relays calculation unit 14 calculates the number of relays that are turned off from the input terminal value, and compares and determines the calculated value with the determination unit 16.
supply to

On the other hand, the on/off command value calculation unit 13 constantly calculates the on/off command values output from the on/off command output units 11 and 12 and supplies them to the comparison/judgment unit 16 .

The comparison/determination section 16 compares the bit value of the off command with the calculated number of off relays.

As a result, if the off command and the number of off relays are different, it is recognized that an abnormality has occurred in the final output stage of the external output section 5 or 6, and the alarm output section is outputted via the output abnormality detection signal output section 17. An output abnormality detection signal is output to 7.

As a result, the alarm device 8 sounds an alarm or lights up the alarm lamp, thereby notifying the external output section 5 or 6 that an abnormality has occurred.

In this way, according to this embodiment, it is possible to constantly check whether the external output section, which is the final output stage of the sequence controller, is in an abnormal state that cannot be turned off, and to issue an alarm.

[Effects of the Invention] As described above, according to the present invention, in the sequence controller parallel operation device, it is possible to promptly detect an abnormality in which the output cannot be turned off due to a failure in the external output section of the sequence controller.

[Brief explanation of drawings]

FIG. 1 is an overall configuration diagram of an embodiment of an output abnormality detection device for a sequence controller parallel operation device according to the present invention, and FIG.
The figure shows the configuration of the external output board in the same embodiment, Figure 3 shows the configuration of the external analog current input section and off-relay detection circuit in the same embodiment, and Figure 4 shows an outline of a conventional sequence controller parallel operation device. FIG. 1.2...Sequence controller main body 4...External output board 6...External output section 7...Alarm output section 8...Alarm device 0...External analog current input section 1.12... -On/off command output section 3...On/off command value calculation section 4...Off relay number calculation section 5...Current value input section 6...Comparison/judgment section 7...Output abnormality detection signal output section 3゜5゜

Claims (1)

[Scope of Claims] A sequence controller parallel operation device that operates in parallel according to the same program and outputs on/off commands to a load via an external output unit, comprising: means for converting the output state of the load side into a current and taking in the load; means for comparing the off command value supplied to the output unit with a current conversion value of the output state on the load side at this time, and determining that the external output section is abnormal if the off command value and the current conversion value do not match. 1. An output abnormality detection device for a sequence controller parallel operation device, comprising: means for outputting an output abnormality detection signal based on the output signal.