JPS5979116A - Indication controller - Google Patents

Abstract

PURPOSE:To make the processing of the safe operation of a control system adequate, by supplying a measured value signal from a signal generating circuit part to a driving part of a measured value indicator to indicate the measured value even if an incorporated microprocessor or the like becomes abnormal. CONSTITUTION:Input signals AI1-AIn selected by a multiplexer 1 pass through voltage-frequency converter 3 and a counter 4 and are stored in an RAM8 under the control of a microprocessor muP6. The signal AI1 is subjected to data conversion as a measured value of the PID control operation and is supplied as data I indicating a bar graph shape on an indicator 12 through an output port 9 to a selector 10. The selector 10 selects measurement indicating data H from a latch circuit 17 and data I and sends them to the indicating part 12. A watchdog timer 2 detects the abnormal operation of the processor 6, and a detection signal A resets the port 9, and a signal selecting data K of an output port 5 is changed to data by which the signal AI1 is selected.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Application of the Invention] The present invention relates to an indicating controller, and more particularly to an indicating controller that has a built-in microprocessor and is capable of performing various calculations in addition to PID control operations.

[Prior art]

In the past, indicating controllers with a built-in microprocessor used an indicator that indicated measured values and target values, and an indicator that operated with analog signals.However, in recent years, liquid crystal, LEIJ, Indicators using fluorescent display tubes, plasma displays, etc. are used as indicators for measured values and target values of indicating controllers because they can be driven by digital signals and are easy to maintain.

However, if the meter becomes abnormal due to a failure of the microprocessor or a change in the data in the ROM storing the program, there is a problem in that the correct data of the measured value is not indicated.

[Purpose of the invention]

SUMMARY OF THE INVENTION An object of the present invention is to provide an indicating controller that can indicate a measured value even if a microprocessor or the like within the indicating controller becomes abnormal.

[Summary of the invention]

The present invention has a generating circuit section for the measured value (g) that is supplied to the drive circuit section of the indicator, independent of the circuit section that supplies the measured value to the microprocessor. The signal generating circuit section of the device supplies a measured value signal to the driving section of the measured value indicator.

[Embodiments of the invention]

The present invention will be explained in detail with reference to FIG. In Figure 1,
The multiplexer 1 receives a plurality of analog input signals AIL~
AIn is selected by signal K.

The input signal selected by 1 is output to the voltage/frequency converter 3 as a digital signal B, and is output to the counter 4 as a digital signal B.
The microprocessor 6 is operated according to the program stored in 7, and the analog input signal AIL is stored in AM8. Then, the data (2) which instructs the indicator 12 in the form of a bar graph as a measurement value is outputted to the selector 10 by valving the output port 9.10 selects the measurement instruction data H and data I from the latch circuit 17. It is composed of a single OR circuit and outputs data J to the indicator drive circuit 11. 11 supplies signals A1 to A for driving the bar graph indicator 12 to 12;
12 indicates the measured value signal AIL in the form of a bar graph. Here, data J is expressed in binary numbers, and each signal is 20+2
', 22, 23. .

The weights are 24, 25, and 26. For this reason 1
1 is supplied with a CLOCK for reading the value of data J, and further outputs a signal C for counting this CLOCK and refreshing 12 at a constant cycle. This signal C is input to the funshot circuit 13,
It becomes a refresh signal.

The watchdog timer 2 detects whether the microprocessor 6 is operating normally and outputs a signal A. This signal A resets 9 when 6 becomes a different division, sets all data ■ to 0'', and converts signal selection data K of 1 output from output port 5 to data selected by AIL. Therefore, when 2 operates, the AII signal is converted to the 2nd frequency by 3, and A
It passes through the ND circuit 15 and becomes the signal E. This signal E is converted into the same binary number as the data 2 by the counter 6, latched by the latch circuit 17, and rewritten at a constant cycle by the refresh signal.

The one-shot circuit 14 is only for outputting 16 reset signals F, and is activated by the refresh signal.
After the value obtained by counting the signal E for a certain period at 16 is latched at 17, the reset signal F is output. FIG. 2 shows a waveform diagram of the main signals.

In this embodiment, as shown in FIG.
, the frequency of OCK is counted, and a refresh signal is created at 100 kasonto. Signal a is a signal from output port 9, and b, ctd is a signal from output port 17 in this embodiment. The signal J is a measured value signal, and after the reset signal A is activated, the two refresh cycles are as follows.
Although the measured value data is not accurate (between signals c and b), 1
If the period is 100Hz, it is 0.02 seconds, which is no problem. In this embodiment, signal multiplexer 1 and A
Since the voltage/frequency converter 3, which is a /'D converter, is shared, the configuration is simple, and it is effective in improving maintainability and reliability, and can be provided easily and easily.

〔Effect of the invention〕

According to the present invention, since the target measurement value of the control system is instructed even when the microprocessor or the like is abnormal, there is an effect that the safe operation of the control system can be appropriately processed.

[Brief explanation of drawings]

FIG.
The figure is a diagram showing the operation signals of FIG. 1. 1...Multiplexer, 2 river watchdog timer
23... Voltage/frequency converter, 4... Counter, 6
...Microprocessor, 5.9...Output port,
10...0 circuit, 11...indicator drive section, 12...
... Bar graph indicator, 16 river counter, 17... latch circuit, 13.14 river one shot circuit.゛Thousand? rJJ Koichi

Claims (1)

[Claims] 1. In an indicating controller that is equipped with a multiplexer for selecting an input signal and a voltage/frequency converter, the internal arithmetic circuit processes the measured value signal and supplies it to the indicator drive circuit. is equipped with a counter that independently inputs the signals from the multiplexer and the voltage/frequency converter and counts the input signals between the signal from the circuit for detecting an abnormality in the arithmetic circuit section and the constant period signal, It has a latch circuit that holds the value of this counter for a fixed period, and a circuit that selects the output signal of the latch circuit and the output signal from the internal arithmetic processing section, and the output signal of this selection circuit drives the indicator. An indicating controller characterized by having a circuit section for supplying a signal to a circuit.