JP2769272B2 - Input processing card and output processing card - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is used in a digital main control unit which takes in an analog signal from an input terminal of a plant transmitter or the like and controls and monitors a plant control device based on the signal. The present invention relates to an analog signal input processing card and a digital signal output processing card.

[0002]

2. Description of the Related Art FIG. 3 is a block diagram showing an analog signal processing device used in a conventional digital main control unit. In FIG. 3, 1 is a main CPU, 2 is a monitoring monitor, 3 is a memory, and 4 is a memory. An analog input card 5 for inputting an output of the signal conversion card 11 as an input processing card, and a digital output card 5 for outputting a digital switching signal when testing the signal conversion card 11, which are operated by the main CPU 1 or the like. The control unit 6 is configured. Reference numeral 7 denotes a test signal switching circuit, 8 denotes an input circuit, 9 denotes an active filter, and these circuits constitute a signal conversion card 11 for outputting an analog signal to the analog input card 4. Reference numeral 12 denotes a transmitter as an input terminal, which is mounted on the site for detecting a process signal of a plant.
Be killed.

Next, the operation will be described. The analog signal of the transmitter 12 is normally input to the input circuit 8 in the signal conversion card 11 via the test signal switching circuit,
Further, after being converted into a reference signal of 1 to 5 V through the active filter 9, the reference signal is supplied to the main control unit 6. The main CPU 1 inputs an analog signal from the signal conversion card 11 via the analog input card 4, converts the analog signal into a digital signal after A / D conversion. On the other hand, the main CPU 1
Sends a 0% and 100% reference signal switching command to the signal conversion card 11, and converts the read value of the analog input card 4 at that time into a digital signal. Based on the read value of the reference signal, the error (deviation) of the signal conversion card with respect to the process signal is automatically corrected using the following equation. Xtemp = (X-CL) / (CH-CL) × 3200
+800 where CH is a 100% reference signal input count value, CL is a 0% reference signal input count value, X is an actual input count value,
Xtemp is the count value after correction, and the correction processing characteristics are shown in FIG.

[0004]

Since the conventional signal conversion processing circuit of the digital main control section is constructed as described above, the main CPU 1 controls the signal conversion card 1.
It is necessary to periodically execute a process for generating a test switching command and automatically correct a process signal for the automatic correction of 1, which places a heavy burden on the main CPU. Further, there is a problem that the timing of the test switching is affected by the calculation load of the main CPU 1 and the speed-up is limited.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and has a main CPU of a main control unit.
It is an object of the present invention to provide an analog signal input processing card capable of performing automatic correction and filter processing of an analog signal sequentially at a high speed without being affected by the processing load of the analog signal. It is another object of the present invention to obtain an output processing card for converting a digital signal from a main control unit into an analog signal and supplying an automatically corrected and filtered process signal to an output terminal.

[0006]

The input processing card according to the first aspect of the present invention has a dedicated signal processing processor built in the input processing card.
A test switching command and automatic correction are performed, and the corrected digital signal is transmitted to the main CPU of the main control unit.

An output processing card according to a second aspect of the present invention has a dedicated signal processing processor built in the output processing card. The dedicated signal processing processor performs a test switching command and performs automatic correction, and corrects the corrected analog signal. Is transmitted to the operation terminal.

[0008]

In the input processing card according to the first aspect of the present invention, after the dedicated signal processor performs test switching and automatic correction of the analog signal from the input terminal, the signal is transmitted to the main control unit.

In the output processing card according to the second aspect of the invention, the dedicated signal processor performs test switching and automatic correction of the process signal from the main control unit, and then outputs the analog signal to the operation terminal.

[0010]

[Embodiment 1] Hereinafter, a first embodiment of the present invention will be described with reference to FIG. In the drawing, the same components as those in FIG. 3 are denoted by the same reference numerals. In FIG. 1, reference numeral 30 denotes an input processing card for converting an analog signal (eg, 4 to 20 mA) of a transmitter into count data (bit information that can be recognized by a CPU);
Is a bus master card that performs a serial transmission interface with the input processing card 30, and 24 is the input processing card 3
0, a signal processor provided exclusively for 0, 25, a serial interface for serially inputting the output of an A / D converter 29, 26, a work memory, 27, a bus slave for serial transmission to the main control unit 6, and 28, 0 %, 10
Switching signal output means for outputting a digital signal for a test switching command to a 0% reference signal. The signal processor 24 includes a processing unit 31 for active filter processing and automatic correction processing based on a software processing function.

Next, the operation will be described. The dedicated signal processor 24 switches the A / D converter 29 from the switching circuit 7.
And the amount of process from the transmitter 12 converted to a digital signal via the serial interface 25. On the other hand, the signal processor 24
In the next operation, digital output for test switching command is performed from the switching signal output means 28, the process signal is separated by the switching circuit 7, and the reference signal generator 10 is controlled to 0% and 100%.
Switch to the reference signal. The input signal at this time is read via the A / D converter 29. The processing unit 31 of the signal processor 24 processes these process signals, the 0% reference signal,
Active filter processing (processing to remove high-frequency noise with a low-pass filter or the like) based on a known operation on digital data of a 100% reference signal, and automatic correction (calibration) of a process signal by obtaining a linear conversion coefficient of an input line Processing). The above processing is performed at a high speed every cycle.

On the other hand, the corrected data is transmitted to the main CPU 1 of the main control unit 6 via a serial transmission bus and used for control calculations. Also, digital data of the 0% and 100% reference signals are serially transmitted to the main CPU 1 and the read count of the 0% and 100% reference signals is read. Can be grasped for each input signal. The main control unit 6 receives a digital signal which is received by the transmitter 12 and processed by the input processing card 30, outputs an analog signal via the output processing card 35, and operates the valve 34 or an operating terminal such as a valve. Will be controlled.

Embodiment 2 FIG. Next, a second embodiment will be described. In the first embodiment described above, the present invention is applied to the input processing card 11 for inputting a process signal. However, as shown in FIG. The present invention can also be applied to an output processing card 35 for controlling an operation terminal such as. That is, the output processing card 35 has a serial interface 36, a D / A
By providing the converter 32 and the output circuit 33, the process signal is output to the operation end of the valve 34 or the like, and the function is changed as an output processing card for controlling this.
In this case, the output analog signal (process signal) of the output circuit 33 is read back to the input circuit 8 side,
By reading the reference signal generator 10, the output analog signal can be sequentially and automatically corrected, and the analog process signal thus automatically corrected is finally supplied to the valve 34. As a result, the CPU incorporated in the signal conditioner card performs automatic calibration at high speed, so that the accuracy change due to the ambient temperature can be automatically corrected immediately, and the drift of the analog output circuit due to the change in the ambient temperature. Does not need to be considered, and a circuit having excellent environmental resistance can be obtained. Further, if serial transmission is performed between the input / output processing card and the main control unit 6, the number of signal cables can be greatly reduced, and the apparatus can be configured at low cost.

[0014]

As described above, according to the first aspect, a dedicated signal processor is built in the input processing card.
Since the automatic switching of the test switching command and the A / D conversion process and the signal input from the input terminal are performed and the corrected digital signal is supplied to the main control unit, the main CPU of the main control unit is provided with the digital signal. Regardless of the load,
At high speed, automatic correction and filtering of an input process signal can be performed. As a result, an input processing card having excellent environmental resistance without having to consider the drift of the analog circuit due to a change in ambient temperature can be obtained.

According to the second aspect of the present invention, a dedicated signal processing processor is incorporated in the output processing card, and a test switching command and A / D conversion processing and automatic correction of a process signal to be supplied to the operation terminal are performed. So that the corrected analog signal is supplied to the main controller.
Automatic correction and filtering of a process signal to be output can be performed at high speed regardless of the load on the main CPU in the main control unit. As a result, it is possible to obtain an output processing card having excellent environmental resistance which does not need to consider the drift of the analog circuit due to a change in the ambient temperature.

[Brief description of the drawings]

FIG. 1 is a system configuration diagram showing a first embodiment of the present invention.

FIG. 2 is a system configuration diagram showing a second embodiment of the present invention.

FIG. 3 is a configuration diagram illustrating an example of a signal conversion circuit of a conventional digital main control unit.

FIG. 4 is a diagram showing correction processing characteristics of the carburetion processing.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Main CPU 2 Monitoring monitor 3 Memory 4 Analog input card 5 Digital output card 6 Main control unit 7 Test switching circuit 8 Input circuit 9 Active filter 10 Reference signal generator 11 Signal conversion card 12 Transmitter 21 Serial transmission bus master 22 Modem 23 Modem 24 signal processor 25 A / D conversion serial interface 26 memory 27 serial transmission bus slave 28 switching signal output circuit 29 A / D converter 30 input processing card 31 software processing unit

Claims (2)

(57) [Claims] 1. A signal input target of a transmitter or the like.
The input analog signal from one input terminal is converted into a digital signal, and the signal is corrected to an appropriate value and the analog signal is processed.
Met input processing cards to be output to the main control unit of the management device
Te, a switching signal output means for selecting switching of the reference signal from the input analog signal and the reference signal generator, an AD converter for converting the signal selected by the switching signal output means into a digital signal, the switching A signal processor for controlling signal output means and inputting and calculating a digital signal from the AD conversion means via a serial interface to perform active filter processing and automatic correction processing; card. 2. An output processing card which converts a digital signal from a main control section of an analog signal processing device into an analog signal, corrects the signal to an appropriate value, and supplies it as a process signal to an operation terminal such as a valve. Switching signal output means for selectively switching between a process signal obtained by reading back the process signal and a reference signal from a reference signal generator, and AD conversion means for converting the signal selected by the switching signal output means into a digital signal And a signal processor for controlling the switching signal output means, inputting and calculating a digital signal from the AD conversion means via a serial interface, and performing active filter processing and automatic correction processing. And output processing card.