JP3260005B2 - A / D conversion processing method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an A / D conversion processing system used in a processing board for taking in an analog signal, A / D converting the analog signal and processing it.

[0002]

2. Description of the Related Art A processing board which is arranged in a computer for performing various processes, takes in an analog signal such as a power supply voltage in the computer, and processes the analog signal, takes in the analog signal, performs A / D conversion, and generates data. An A / D converter circuit, and a CPU such as a microprocessor that processes data obtained by the A / D converter circuit;
A ROM storing a program for defining the operation of the CPU and various constant data, a RAM used as a work area of the CPU, a serial input / output circuit for transmitting processing results of the CPU to a host device, and the like; It has.

Then, an analog signal such as a power supply voltage to be processed is taken in, the data is A / D converted to generate data, and the data is processed based on a program stored in a ROM. The data obtained by this processing operation is transmitted to the host computer.

[0004]

However, the above-mentioned conventional processing board has the following problems.

That is, an analog signal to be processed is fetched, A / D converted by an A / D converter circuit to create data, and this data is processed. Quantization errors occur due to variations in constituent elements.

For this reason, conventionally, the quantization error is reduced by reducing the variation of the elements constituting the A / D converter circuit or by using a high-precision element. In order to reduce the variation, it is necessary to perform a troublesome operation such as a hardware adjustment operation, and there is a problem that using a high-precision element increases the cost.

In view of the above circumstances, the present invention reduces the quantization error when converting an analog signal into a digital signal without using expensive elements and without performing adjustment work such as hardware. It is an object of the present invention to provide an A / D conversion processing method capable of greatly improving processing accuracy.

[0008]

In order to achieve the above object, an A / D conversion processing system according to the present invention comprises a plurality of analog / digital converters.
Input signal is input and the selected analog input signal is
An A / D conversion circuit for performing A / D conversion on one of the signals;
Select one of a number of analog input signals and perform the A / D conversion
The digital signal from the circuit is corrected and output to the host device.
And a processing circuit for controlling the host device.
Each analog input according to the threshold setting command from the
The threshold for the signal is stored in internal memory,
Subsequently, the plurality of analog input signals are appropriately selected and
Output from the A / D conversion circuit and the analog input
Compare the preset value corresponding to the signal with the preset value.
As a correction value for each analog input signal.
Command to start measurement from the higher-level device.
Select one of the plurality of analog input signals in response to the
A digital signal from the A / D conversion circuit;
The analog input signal read from the internal memory
The correction processing is performed by calculating the corresponding correction value.
The processed value corresponds to the corresponding value read from the internal memory.
If an abnormality is detected by comparing with a threshold value,
It is characterized in that abnormality notification is performed.

[0009]

According to the above arrangement, in response to a command from a higher-level device,
Before starting the measurement,
Stored in the internal memory, and
Output signal from the A / D conversion circuit
And a preset setting corresponding to the analog input signal.
Compared to the fixed value, the difference is taken as the correction value,
Each input signal is stored in the internal memory. Then, open the measurement
One of the multiple analog input signals in response to the start command
And a digital signal from the A / D conversion circuit,
Corresponds to the analog input signal read from the internal memory
And the correction value is calculated. This correction
Processed value and corresponding threshold read from internal memory
If an error is detected by comparing the value with the
Knowledge is done.

[0010]

FIG. 1 is a block diagram showing an example of a processing board to which an embodiment of an A / D conversion processing system according to the present invention is applied.

A processing board 1 shown in FIG. 1 connects an A / D converter circuit 2, a serial input / output circuit (SIO) 3, a processing circuit 4, and these A / D converter circuits 2 to 4 mutually. And an analog signal to be processed, for example, an analog signal such as a power supply voltage and a temperature signal in a computer, and A / D-converting the analog signal. After the data is corrected, the data is processed. When it is determined that the data needs to be transmitted to the host device based on the processing result, the processing result is transmitted to the host device 6 via the serial input / output circuit 3.

The A / D converter circuit 2 includes the processing circuit 4
Input terminal to ninth input terminal based on a selection command output from
An analog signal input to the input terminal is selected, and the selected analog signal is A / D converted to generate data and supplied to the processing circuit 4.

When the parallel input / output circuit 3 outputs the parallel data from the processing circuit 4, the serial input / output circuit 3 converts the data into serial data and transmits it to the host device 6. When serial format data is output from the host device 6, it is taken in, converted to parallel format data and supplied to the processing circuit 4.

The processing circuit 4 includes a CPU 10 such as a microprocessor for performing various data processing,
ROM 11 that stores a program defining various operations and various constant data, RAM 12 used as a work area of the CPU 10, various correction data used in the CPU 10, for example, the A / D converter circuit (Electrically erasable ROM) for storing correction value data and the like obtained based on the difference between the measurement data of the reference data (for example, power supply voltage) obtained by the method 2 and the set value data of the reference data. A correction value calculation process for controlling the A / D converter circuit 2 based on a program stored in the ROM 11 to A / D convert a power supply voltage and a temperature signal to calculate a correction value. And an A / D converter that controls the A / D converter circuit 2 to A / D convert an analog signal to generate data.
D conversion processing, correction processing for correcting data obtained by the A / D conversion processing with correction value data obtained by the correction value calculation processing, processing processing for processing data obtained by this correction processing, A process such as a process of supplying data obtained by the / D conversion process and the processing process to the serial input / output circuit 3 and transmitting the data to the higher-level device 6 is performed.

Next, the operation of this embodiment will be described with reference to the flowchart shown in FIG.

First, when a series of processing (other processing) is completed, the CPU 10 of the processing board 1 outputs a threshold setting command from the host device 6 and checks whether or not this is received by the serial input / output circuit 3. Then, if the threshold setting command has been received (step ST1), A / A
The threshold value for each of the first to ninth input terminals of the D converter circuit 2 is fetched and stored in the EEPROM 13 (step ST2).

Thereafter, the CPU 10 executes a correction value calculation process 1
Step 5 is executed.

In this correction value calculation processing 15, the CPU 1
0 first performs A / D conversion on an analog signal to be measured input to the first input terminal of the A / D converter circuit 2, for example, a + 5V power supply voltage signal whose voltage value is known in advance (step ST3). ), The value of the voltage data obtained by the A / D conversion processing, and the set value data indicating the value of the power supply voltage signal (the set value data is +5
V (indicating the value of V), and the difference is stored as a correction value (step ST4) in the EEPROM 13 (step ST5).

Thereafter, the CPU 10 performs the above-described correction value calculation processing for the remaining terminals of the A / D converter circuit 2, that is, the second to ninth input terminals, and executes the above-described correction processing. The correction value data is calculated for each terminal and stored in the EEPROM 13 (steps ST3 to ST6).

After the correction value calculation processing 15 is completed, if a measurement start command is output from the host device 6 (step ST7), the CPU 10 determines whether the correction value calculation processing 15 has been completed. A check is made (step ST8), and if the correction value calculation processing 15 is not completed, the unset status information is created, supplied to the serial input / output circuit 3, and transmitted to the host device 6 (step ST9). ).

When the measurement start command is output from the host device 6 and the correction value calculation processing 15 has been completed, the CPU 10 starts the voltage measurement processing 16.

In the voltage measurement process 16, the CPU 10 first selects any one of the first to ninth input terminals of the A / D converter circuit 2, and selects the first to ninth input terminals.
A / D conversion is performed on the analog signal input to the input terminal to generate data (step ST1).
0), among the correction value data stored in the EEPROM 13, the correction value data corresponding to the selected input terminal is read (step ST11), and the correction value data
After adding the data output from the A / D converter circuit 2 to create corrected data (step ST
12) Based on the data, look up a voltage conversion table stored in the ROM 11, convert the data to voltage value data, and store this in the RAM 12 (step ST13).

Thereafter, the CPU 10 sequentially selects the remaining input terminals from the first to ninth input terminals of the A / D converter circuit 2 and repeats the above-described processing.

In parallel with this operation, the CPU 10 compares each of the voltage value data obtained by the above-described voltage measurement processing 16 with each of the threshold values stored in the EEPROM 13 to correspond. When there is voltage value data out of the range of the threshold value, voltage abnormality detection information is generated, supplied to the serial input / output circuit 3, and transmitted to the host device 6.

As described above, in this embodiment, when the host device 6 outputs the threshold setting command, A /
The analog signal whose voltage value is known in advance by the D converter circuit 2 is A / D converted, and the A / D conversion is performed.
The correction value data is calculated by comparing the value of the data obtained by the conversion operation with the original value of the analog signal, and when performing the actual voltage measurement operation, based on the correction value data obtained in advance. Since the data output from the A / D converter circuit 2 is corrected to correct the quantization error of the A / D converter circuit 2, adjustment work of hardware and the like can be performed without using expensive elements. , The quantization error when converting an analog signal into a digital signal can be reduced, and the processing accuracy can be greatly improved.

In the above-described embodiment, when the threshold value setting command is output from the host device 6, the correction value calculation processing 15 is executed.
When the value of the analog signal input to the converter circuit 2 is accurately adjusted, for example, at the time of system startup, the correction value calculation processing 15 may be executed immediately after the power supply voltage is adjusted. good.

[0027]

As described above, according to the present invention, a quantization error when converting an analog signal into a digital signal without using expensive elements and without performing adjustment work such as hardware. And the processing accuracy can be greatly improved.

[Brief description of the drawings]

FIG. 1 is a block diagram showing an example of a processing board to which an embodiment of an A / D conversion processing system according to the present invention is applied.

FIG. 2 is a flowchart showing an operation example of the processing board shown in FIG. 1;

[Explanation of symbols]

Reference Signs List 1 processing board 2 A / D converter circuit 3 serial input / output circuit 4 processing circuit 5 bus 6 host device 10 CPU (correction value data calculation unit, voltage data correction unit) 11 ROM 12 RAM 13 EEPROM

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-63-116523 (JP, A) JP-A-3-179919 (JP, A) JP-A-1-94724 (JP, A) JP-A-63-116 222516 (JP, A) (58) Field surveyed (Int. Cl. ⁷ , DB name) G06F 3/05 311

Claims (1)

(57) [Claims] A plurality of analog input signals are input and selected.
A / D conversion is performed on one of the selected analog input signals.
A / D conversion circuit and one of the plurality of analog input signals are selected,
The digital signal from the D conversion circuit is corrected and
And a processing circuit for outputting the location, the processing circuit in accordance with the threshold setting command from the host system, the A
Threshold value for analog input signal is stored in internal memory
Subsequently, the plurality of analog input signals are appropriately selected.
And the output from the A / D conversion circuit and the
Compare with the preset value corresponding to the analog input signal.
And comparing the difference with the analog input signal
Stored in the internal memory every time, and in response to a measurement start command from the higher-level device,
One of a plurality of analog input signals is selected, and the A /
From the digital signal from the D conversion circuit and from the internal memory
The correction value corresponding to the read analog input signal
And a correction process is performed to calculate a pair of the corrected value and the value read from the internal memory.
If an abnormality is detected by comparing the
It is characterized by performing abnormality notification to a higher-level device.
A / D conversion processing method.