JPS63145502A - Back-up device for trouble of digital controller - Google Patents

Abstract

PURPOSE:To reduce the load of the CPU by controlling a process based on the signal obtained by applying D/A conversion to the output of an up-down counter when a main CPU has a trouble. CONSTITUTION:When a main CPU 1 has a trouble, an output is outputted from a trouble monitor part 16 together with a signal A outputted from an OR circuit 17. While an auto/manual switch 19 is changed to a manual side. Thus the data set at an up-down counter 4 is manually changed and a process 8 is manually controlled. At the same time, the output signal of the part 16 is also supplied to a digital display CRT 15 and the digital displays PV, SV and MV of a digital display device 14 are erased. The signal A is also supplied to a secondary CPU 9 when the CPU 1 has a trouble. The CPU 9 uses the data on the measured value PV and the manipulated variable MV of the process 8 supplied via an A/D converter 9a to actuate a bar display device for display of bars. In such a way, the load of the CPU 1 is reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION A. Field of Industrial Application The present invention relates to a failure backup device for a digital controller that performs process control.

B3 Summary of the Invention The present invention provides a digital controller that captures information indicating the state of a process in the form of a digital signal into a main processing unit, and controls the process by specifying the operating amount of the process based on the captured digital information. , When the main processing unit is normal, the operation amount calculated by the main processing unit is set in an up/down counter, the process is controlled based on the output of the counter, and process information is displayed as a bar, and the main processing unit When a failure occurs in the up/down counter, the data set in the up/down counter is manually changed, and the process is controlled based on the changed data, and the sub-processing process information is taken in without passing through the main processing unit. By displaying process information in bars using the processing unit, it is possible to ensure process control and data display in the event of a failure of the main processing unit, and it also reduces the burden on the main processing unit for displaying process data. This is what I did.

C0 Conventional Technology In a conventional controller for controlling a process, an analog display method (display using an analog meter, etc.) was used to display measured values PV, manipulated values MV, set values SV, etc. However, in recent years, information indicating the state of the process is imported into the central processing unit (hereinafter abbreviated as CPU) as a digital signal, and based on the imported digital information, the amount of operation of the process is specified, and the measured value PV
.

Digital controllers configured to digitally display operating values MV and set values Sv have been employed.

D. Problems to be Solved by the Invention The digital controller configured as described above necessarily uses the CPU for display, and therefore has the disadvantage that the processing load on the CPU becomes heavy. In addition, in the event of a CPU failure, the measured value PV, operating value MV, and set value S in process control
There was a problem that it became impossible to display V, etc.

The present invention has been made in view of the above points, and its purpose is to reduce the burden on the CPU for displaying data, to ensure manual backup in the event of a CPU failure; An object of the present invention is to provide a failure backup device for a digital controller that can perform display.

Means for Solving Problem E5 The present invention provides an arithmetic operation in which information indicating the state of the process is taken into the main processing unit in the form of a digital signal, and the amount of operation of the process is specified by a predetermined program based on the taken-in digital information. The digital controller has an internal analog-to-digital converter, and when the main processing section is normal, takes in digital information derived from the main processing section and processes it based on the calculation results. At the same time, when the main processing section fails, a sub processing section takes in digital information of the process guided through the analog-to-digital converter and processes it, and when the main processing section is normal, the main processing section and a bar display having a plurality of light emitting elements arranged in a bar shape and displaying the digital information of the process derived from the sub-processing section as a bar. , an up/down counter in which data representing the operation amount of the process specified by the main processing unit is set; and a data change that manually changes the data set in the up/down counter when the main processing unit fails. The process is controlled based on a signal obtained by digital-to-analog conversion of the output of the up-down counter.

When the F1 main processing section is normal, the operation amount calculated by the main processing section is set in an up/down counter, and the process is controlled based on the output of the counter. At this time, the sub-processing section takes in digital information indicating the state of the process guided by the main processing section, processes it, and supplies it to the bar display.

This causes the bar display to show the process measurement value P■.

Displays the operation value MV, set value SV, etc. as a bar. In this way, the bar display of the measured value PV, operation value MV, set value SV, etc. (these two are handled by the sub-processing section, reduces the burden on the main processing section. In the event of a failure, the process is manually controlled by manually changing the data set in the up/down counter using a data change circuit.At this time, the sub-processing section uses analog data without passing through the main processing section. The process information is taken in through the digital converter, processed and supplied to the bar display.Thereby, the bar display shows the process measured value PV even if the main processing unit is out of order.

Display the operation value MV as a bar. In this way, even if the main processing unit fails, the process can be reliably controlled manually and process data can be displayed.

G. Embodiment Hereinafter, an embodiment of the present invention will be described with reference to the drawings. The drawing is a block diagram when the device of the present invention is applied to flow control, and l is the main CP of the digital controller.
It is U. This main CPU takes in information indicating the state of the process via an analog-to-digital converter (hereinafter abbreviated as A/D converter) 2, and also performs calculations to obtain the operation amount of the process using the taken in digital information. conduct. The calculation result of the main CPU (signal corresponding to the manipulated variable) is set in the up/down counter 4 via the buffer 3. The output of the up/down counter 4 is sent to the buffer 5 and digitally as the manipulated value (MVA).
The signal is supplied to the A/D converter 2 via an analog converter (hereinafter referred to as a D/A converter) 6, and then to the V/I converter 7. The V/I converter 7 converts the voltage signal of, for example, 1 to 5 V output from the D/A converter 6 to 4 to 20 mA.
is converted into a current signal and output as a manipulated value MV.

The process (valve) 8 is controlled by the output signal of the V/I converter 7. Reference numeral 9 denotes a sub-CPU (for example, a one-chip CPU) equipped with an A/D conversion W9a inside.

The sub CPU 9 takes in and processes digital information (information indicating the status of the process 8) led from the main CPU via the one-chip interface 10 when the main CPU is normal, and also processes digital information when the main CPU fails.
Process information (MVA, PV) led from the A converter 6 and the process 8 via the A/D converter 91 is taken in and processed. Reference numeral 11 indicates process information (measured value P■,
This is a bar display device that displays the operating value MV and set value SV as a bar by causing a plurality of light emitting elements arranged in a bar shape to emit light.

23 is a data memory, 13 is a system program memory, and 14 is a digital display driven and controlled by a digital display CTR (controller) 15. This digital display 14 digitally displays the measured value PV, the manipulated value MV, and the set value S■. Reference numeral 16 denotes a failure monitoring unit that outputs an output when the main CPUI fails. Failure monitoring section 16
The output of is the OR circuit I7 and the digital display CTRl.
5. 18 is an output port, the output of which is supplied to the OR circuit 17. The output signal of the OR circuit 17 is supplied to the automatic/manual switch 19 as a switching signal, and is also supplied to the failure indicator lamp 20 and the sub CPU 9. Reference numerals 21a and 21b are operation switches for manually operating the counter 4 up and down when the automatic/manual switch 19 is switched to the manual side. 22 is a bus.

In the device configured as above, the main CPU
It is assumed that the process 8 is operating normally and the process 8 is controlled based on the calculation result of the nuclear CPU.

In this case, the upper CPU passes the process 8 through the A/D converter 2 according to the program in the system program memory 13.
The operations ffiMVA, measurements (i! PV, etc.) are taken in and the information is supplied to the sub CPU 9 via the one-step interface 10, while the taken in information is processed and the digital display CTRl 5 is driven to display the operation value MV.
, measurement (rip v ), and set value Sv are displayed on the digital display 14 .

W'l CPU 9 is a one-deep interface
The process information supplied from O is processed and the bar display 11 is driven based on the result of the calculation. As a result, the bar display 11 displays the operating value MV, measured value pv, and set value SV.
is displayed as a bar.

Next, when the main CPU 1 fails, the failure monitoring section 1G outputs an output, and the OR circuit 17 outputs a signal. This signal A lights up the failure indicator lamp 20 and switches the automatic/manual switch 19 to the manual side (forced manual mode M). Therefore, operation switch 2
If you operate 1a and 21b, a.
The data set in 8 is manually changed, and the process 8 is controlled manually. Further, the output signal of the failure monitoring section 1G is also supplied to the digital display CTR15. Above this, the digital display of the digital display 14 (P
V, SV, MV) are canceled.

In addition, the output signal A of the OR circuit 17 when the main CPUI fails
is also supplied to the sub CPU 9. When this signal A is supplied, the sub CPU 9 does not use the data derived from the main CPU, but instead uses the data of the measured value PV and operation value MV of the process 8 inputted via the A/D converter 9a. Use to display the bar display +1 as a bar.

The check for the opposite side CPU 9 is performed by displaying all the bar indicators 11 up to a specific value when the check switch 24 is turned on. In addition, when the sub CPU 9 breaks down, it is monitored using the digital display on the main CPU.

H. Effects of the Invention As described above, according to the present invention, since the sub-processing section is provided, the burden on the main processing section for displaying process data is reduced. Furthermore, even if the main processing unit fails, the process can be controlled manually using the data change circuit, and the process data can be displayed as a bar.

[Brief explanation of the drawing]

The drawing is a block diagram showing one embodiment of the present invention. l...Main CPU, 4...Up/down counter, 8
...Process, 9...Sub CPU, 9a...A/D
Converter, 11... Bar display, 14... Digital display, 16... Failure monitoring section, 19... Automatic/manual switch, 21a, 21b... Operation switch.

Claims (1)

[Claims] Information indicating the state of the process is taken into the main processing unit as a digital signal, and based on the taken digital information, a calculation is performed to specify the amount of operation of the process using a predetermined program, and the result of the calculation is A digital controller that controls a process based on an internal analog-to-digital converter, and when the main processing section is normal, it takes in and processes digital information derived from the main processing section, and a sub-processing section that takes in and processes digital information of the process guided through the analog-to-digital converter when the processing section is out of order; a digital display that digitally displays information; a bar display that has a plurality of light emitting elements arranged in a bar shape and displays digital information of a process led from the sub-processing section as a bar; and the main processing section. an up-down counter in which data representing the operation amount of the process specified by is set; and a data change circuit that manually changes the data set in the up-down counter in the event of a failure of the main processing unit. A failure backup device for a digital controller, characterized in that a process is controlled based on a signal obtained by digital-to-analog conversion of the output of the up-down counter.