JPS5938801A - Backup system of sequence control - Google Patents

Abstract

PURPOSE:To make it possible that an auxiliary controller follows completely the operation of a faulty main controller, by allowing the data base transferred to a corresponding switching part to include command information to another main controller after the control operation of the main controller. CONSTITUTION:The data base, which includes command information to a main controller MDC2 or MDC1, just after the control operation is transferred from the main controller MDC1 or MDC2 to a variable memory RAMs1 or RAMs2 of a corresponding switching part SW1 or SW2. If a trouble occurs before the transfer of the data base, an auxiliary controller BDC starts the substituting operation retroactively to the time of the preceding transfer of the data base. If a trouble occurs after the transfer of the data base, the auxiliary controller BDC starts the substituting operation retroactively to the time of the transfer of the data base even if the command transmission is already performed.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a backup system for a sequence control device that has one sub-controller as a backup for a plurality of main controllers.

Recently, a duplex system with several main controllers (as opposed to one sub-controller) has generally been adopted.
However, when a failure occurs in one of the main controllers and control is switched to the sub-controller, the standby sub-controller starts a new control operation, so the start situation of the control operation is unspecified. This has the disadvantage that the control operation cannot be taken over smoothly1.The "backup method for sequence control" (Japanese Patent Application No. 120143/1983), which was filed separately by the applicant, is effective when a failure occurs in the main controller. A method has been proposed in which the sub-controller starts the act on behalf of the main controller.

However, when multiple main controllers (El-Ra) malfunctioned after transmitting control calculations, the other controller (P-2) that had received the commands performed control operations based on the commands. Since the sub-controller acting on behalf of the faulty main controller starts the action from the retroactive step, the main controller that has caused the p1 fault due to current process value fluctuations, etc. will not be able to send commands. The operation status of the sub-controller 2 does not always match the state in which the sub-controller 2 performs the operation successfully, and there is a possibility that the substitute operation of the sub-controller and the operation status of other main controllers 2 will be in a mismatched state.

The present invention has an object of fundamentally eliminating such drawbacks of the conventional art, and has a plurality of main controllers and six main controllers that receive database transfers. In the sequence control method in which the sub-controller starts acting on behalf of the operation, the main controller performs control calculations. This is an extremely effective method that completely follows the operation of the main controller in which the sub-controller has failed. , which provides a backup method for sequence control.

Hereinafter, the present invention will be explained in detail with reference to figures showing examples.

FIG. 1 is a block diagram showing the configuration. In this example, the main controller MDC, MDC, the sub-controller BDC, the switching section SW1, and the switch switch are provided. .

MDC! The operating state of the switching unit SWs is monitored.

A director DRT is provided to give commands to the SWi K, and each has a processor C such as a microphone 4 processor.
PU ml e CP U ma a CP U b
e CPU U I.

CPUd is equipped with fixed memory ROMm1 @R
Each of them executes a predetermined operation based on the instructions stored in b*ROMg*ROMd in OMmRAMm1.

The main controllers MDC1 and MDCz also control flowmeters, etc. in the process via interfaces I/F ml, I/F mz and input/output circuits I/Oml and I/Omz, which have functions such as converting analog signals and digital signals. Sensor SSt, 8S
In addition to receiving the output from the valves MV and MVt in the process, it also sends out control outputs to the ICs, and records the control calculations based on the outputs of the sensors sst and SS. JRAMmt is executed while accessing data to the RAM town, thereby determining the output value of the control output, and then controlling the access with the controller.

Note that the main controllers MDCs and MDCz are provided with watchdogs WDTs and VDTs for monitoring the operations of the processors CPUml and CPUmx.
The results of the self-diagnosis periodically performed by U m 1 and CP Umx are sent to the switching units SW1 and SWz via OR gates Gm1 and Gmz, and are also sent to the variable memory RAM ml6. Database f buffer memory B F M m required for control in RAM m1
1 r B FM m z included switching section SWI
, SWz.

In addition, the main controller MDC! 1MDC! and the sub-controller BDCvr- is ~transmission circuit 8Rml*
SRms and SRb are provided, through which commands necessary for controlling the transmission line IJjl:l are exchanged.

On the other hand, switching unit SW'1. SWn is interface I
/Fs1, periodically receives the database from the buffer memory BFMm+ v BFMm* via I/Fms'fr, and transfers this fL to the variable memory RAM5tIR.
A M s 2 is updated and stored sequentially, and the main controller 9 M D Ct is stored. The sub-controller BDC is always on standby, but the main controller MD C1"t'ft:,
ldM D C OR game depending on the occurrence of a problem) Gmt
The fault signal sent from t7tliG m* is sent to the interface I/F a1.
Processor CPU m t or C via s
PUI! When the receiver is received, the interface I /
F vr 1 or I/F s * Through the interface I/F b 1 of the sub-controller BDC, the variable memory RAM 111 receives the database transfer from the RAM 5l, and stores this as its own variable memo')
After storing it in RAMb, control operation is started according to this content, and the input/output circuit I/Omt, which is similar to l10m5, is installed in the interface I/Fb.
/Ob, receives and receives the output from the sensor SSt or SS, performs control calculations to determine the output value of the control output, and applies this to the motor valve MV1 or MVt.
It is intended to be sent to K.

In addition, the director and DRT are connected to the interface I/Fs, I/F as through its own interface
Game) Gmt.

While monitoring the fault signal from Q m 2, when a fault signal occurs, the switch SWl hole is 8Wx and variable memo! Database required for control in JRAMs1 or RAM 112) o-ra BD
Sends a transfer command to transfer the data to the switching unit SW via one interface I/F d.
The switch 81 inside the SW mushroom controls the SS, and until now the main controller MDC1't or MDC
The control output of * is selected and the next state is switched to the state where the control output of the sub-controller BDC is selected.
Information about which controller is currently executing the control operation is stored in RAMd n1.

In addition, the director interface I/Fd2)-
RaU, each"n) Lower MD Ct s MD C
m, BDC each interface I/F m
A control signal is sent to I/F ms, I/Fb, and commands are given to stop the operation and start the substitute operation in response to the occurrence of a fault.

For the control operation in the main and sub-controllers MDCI-MDC and BDC, a cycle for sampling the outputs of the sensor 881 and SS is determined, and control calculations and control outputs are performed according to this sampling cycle. Figure 2 is a flowchart showing the main operating conditions of the main controller MDCI and MDC.
Mm1- Database processing sensor S in RAMmx
After performing control calculations based on the outputs of St and SS1,
1 performance, including information on commands to other main controllers.
Variable memo of calculation results! j'RAMm and then transfer the database to the variable memory RAMm1.
, transfer the database in RAMm5, including command information, to the buffer memories BFMml and BFMml, and then
'LK makes it possible to transfer the database to the switching parts SWI and sw2, and then sends one command I to other main controllers as necessary, and then sends the control output to the motor valves MNt and MV. Do the following.

Therefore, the databases transferred to the variable memories RAM s 1 and RAM @ z of the switching units SVI/'l and SW* are the ones immediately after the six control calculations including the command information, and if one database is transferred. If a failure occurs before the next step, the sub-controller BDC will start acting on your behalf retroactively to the time of the previous Qi database transfer.
One command shall be sent from the sub-controller BDC.1. Since one command has not yet been transmitted from the faulty main controller, the commands from the sub-controller 9BDC will no longer conflict with the commands from the main controller before the fault occurred.

- If a failure occurs after the database is transferred, the secondary controller BDC will
Since the proxy operation is started retroactively to the point in time when the Qi database was transferred, a failure occurs and the sub-controller BDC sends the Qi command (IIR) with the same content as the Qi command transmission from the main controller. The sub-controller BDC completely follows the operation of the main controller that has occurred, and no contradiction occurs in this case as well.

That is, the main controller MDC1t or MDC2
Even if a failure occurs at any point in time, the secondary controller will continue to follow the operations of the failed main controller, and consistency in operation with other primary controllers will be maintained. In Figure 1,
The number of main controllers MDCs % MDCl is increased further, and the switching unit SW! , SWz k may be added, and the function of the director DTR can be changed to the switching unit SWI, SW
The same applies to the case where the control device is accommodated in the control device 2, and the present invention can be applied to control devices having various configurations.

As is clear from the above explanation, according to one aspect of the present invention, even when a plurality of main controllers exchange commands among themselves, there is a Since consistency is maintained, significant effects can be obtained in sequence control for various applications.

BRIEF DESCRIPTION OF THE DRAWINGS The drawings show an embodiment of the present invention, FIG. 1 is a block diagram showing the configuration, and FIG. 2 is a flowchart showing the main operating status of the raw controller. MDCs, MDCz... Main controller,
BDC... Sub controller, SWx - SW2 ・
...Switching unit, CPUmt, CPUmx, cpU,
b's. CPU11, CPU5!・・・Processor, ROM
m+% ROMrr+2, ROMb, ROMm1
% ROM5g・・・Fixed memory, RAMm5, R
AMm2, "RAMb1RAM8K, RAMI spirit...
・Variable memory, WDTml, WDTml... Watchdog timer, BFMm11BFMm2... Buffer memory, I/Fml, I/Fm*, engineering/
Fb1, -I/Fb,, I/Fsl, I/FII
x HH threat 1 interface, I 10mt, 'I
/ Oma, l10b --- input/output circuit, St,
8m...Switch, SSl, SS,...Sensor, MVt -MVt...Motor valve. Patent applicant: Yamatake Honeywell Co., Ltd. Agent Masaki Yamakawa (and one other person) 13-

Claims (1)

[Claims] A plurality of main controllers that perform control calculations and exchange control commands between each other, and a switching unit provided corresponding to each of the main controllers, which is provided with a memo IJ' that receives a database from the soil-containing controller. , when a failure occurs in any of the above-mentioned main controllers.
In a sequence control backup method, the secondary controller starts acting on behalf of the operation from an operation step retroactive from the time when the failure occurred after receiving the transfer of the database from the switching unit corresponding to the failure. A sequence control backup method, wherein each of the main controllers performs the control calculation, transfers the database to the corresponding switching unit, and then transmits the command.