JPH03214816A - Analog data input circuit - Google Patents

Abstract

PURPOSE:To prevent transmission of an erroneous digital data due to a change in a reference voltage by comparing a data subject to A/D conversion with a prescribed set value and correcting the gain of an A/D converter means only when the result of comparison exceeds a prescribed range. CONSTITUTION:An analog data is inputted from input terminals 11,12 and fed to an analog data switching section 3 and converted into a digital data by an A/D converter 5 via an automatic gain control amplifier AGC 4. Then an output is given to a line from an output terminal 13 via a logic section 9 and a line interface section 12. Reference voltage generating sections 21, 22 generate a reference voltage at all times and gives it to a voltage comparator 10 and a switching section 3. The switching section 3 compares the received signal with a comparison data set at a comparison data setting section 7 via a data comparison section 6 by the control of the logic section 9 and corrects automatically the gain of the AGC 4 when there is a dissidence over a prescribed range or over. Thus, an analog data error is detected at an output device side and erroneous transmission of a digital data due to a change in the reference voltage is prevented.

Description

[Detailed description of the invention] ? INDUSTRIAL APPLICATION FIELD] The present invention relates to an analog data input circuit used for data transmission, and particularly to a circuit that converts analog data into digital data using an input device and transmits it, and converts the digital data into analog data using an output device. The present invention relates to an analog data input circuit in an output analog data transmission method.

[Prior Art] When analog data is added to this type of analog data input circuit, the analog data is converted into digital data and sent to an output device.

An example of such an analog data human circuit is shown in FIG.

As shown in Figure 2, analog data is input to input terminal 2.
1,. 21■, the A/D (analog/
(digital) converter 25. A/D converter 2
The analog data input to 5 is converted into digital data and sent to the line interface section 3 via the logic section 29.
0, is output to the line through the output terminal 31.

On the other hand, the reference voltage is constantly generated by the reference voltage generation section 22, and is controlled by the logic section 29 via the buffer 28.
Switch the analog data switching unit 23 to
The signal is input to the A/D converter 25 via the AMP 24. Further, at the same time as switching the analog data switching section 23, the data comparing section 26 is operated under the control of the logic section 29. The reference voltage input to the A/D converter 25 is converted to digital data, guided to the data comparison section 26, and compared with arbitrarily set comparison data in the comparison data setting section 27, and the reference voltage is converted into digital data and is compared with arbitrarily set comparison data in the comparison data setting section 27. If there is a discrepancy, AGC
- Automatically correct the gain of AMP24.

In this way, the input circuit of the conventional analog data transmission method converts the reference voltage into digital data by A/D conversion, compares it with arbitrarily set data, and if there is a discrepancy beyond a given range, the AGC- AMP gain is automatically corrected.

[Problem to be solved by the invention]

The above-mentioned manual circuit of the conventional analog data transmission method 2 automatically corrects the gain to ^CC- based on the voltage value of the reference voltage, so when the reference voltage changes, the AGC-A
The gain of MP also changes. Therefore, the A/D converted digital data also becomes erroneous data, resulting in the disadvantage that erroneous analog data is outputted by the output device.

SUMMARY OF THE INVENTION An object of the present invention is to provide an analog data input circuit that can eliminate such drawbacks and prevent erroneous digital data transmission.

[Means to solve the problem]

The present invention provides an analog data input circuit which, when analog data is added, sends digital data converted from the analog data to a line via an interface section, comprising: a plurality of voltage generating means for generating reference voltages; Alarm means that compares the reference voltages of the means with each other and generates an alarm due to a change in one reference voltage; Conversion means that amplifies the applied selection signal by a set gain and converts it into digital data; logic means for sending digital data from the conversion means to the interface section and sending this alarm to the interface section when an alarm occurs in the alarm means; and under control of the logic means, the analog data and the voltage of l a switching means for switching a reference voltage from the generating means to produce a selection signal; and when the logic unit is activated and the digital data from the converting means is based on the reference voltage, the digital data is converted to a predetermined setting value. and comparing means for correcting the gain of the converting means if the comparison result exceeds a predetermined range.

Further, the present invention provides first and second voltage generators that generate a reference voltage in an analog data input circuit that converts analog data and sends digital data to a line via an interface section when analog data is added. means for comparing the reference voltages of the first and second voltage generating means with each other and generating an alarm due to a change in either of the reference voltages; converting means for amplifying and converting into digital data; logic means for sending the digital data from the converting means to the interface section and sending this alarm to the interface section when an alarm is generated by the alarm means; Under the control of the logic means, the analog data and the first
switching means for switching the reference voltage from the voltage generating means to produce a selection signal; and comparing means for comparing the gain of the converting means with a set value, and correcting the gain of the converting means if the comparison result exceeds a predetermined range.

? In the present invention described above, the alarm means for generating an alarm includes: a voltage comparator that compares reference voltages from the first and second voltage generation means; and an alarm generation section that generates an alarm based on input from the comparator. It is preferable to have the following.

(Example) Next, an example of the present invention will be described with reference to the drawings.

FIG. 1 is a circuit block diagram showing one embodiment of the present invention. This analog data input circuit consists of an analog data switching unit (A-SW) 3, an AGC (Banpha amplifier with automatic gain adjustment function) 4, and an A/D converter (A-SW) 4.
/D) 5, a data comparison section (CoMP) 6, a data setting section 7, a buffer 8, a logic section (LOG) 9, a reference voltage generation section 21.2■, and a voltage comparator (CO?l).
P) 10, an alarm generating section 11, and a line interface section 12.

Such an analog data input circuit has input terminals 11,
Digi the analog data added to 1■? This digital data is sent from the output terminal 13 to an output device not shown in FIG. The output device converts the digital data into analog data and outputs it.

The reference voltage generating section 21.2■ of the analog data input circuit generates a reference voltage.

The analog data switching circuit 3 controls input terminals 1+ . One of the analog data applied to 1z and the reference voltage from the reference voltage generator 2 is selected and sent as an output.

The AGC-AMP 4 amplifies the output from the analog data switching section 3 based on the gain corrected by the data comparison section 6.

A/D converter 5 converts the output from AGC-AMP 4 into digital data.

The data comparison section 6 is operated by a logic section 9 via a buffer 8. The data comparator 6 then receives digital data of the reference voltage sent from the A/D converter 5, and
Arbitrarily in the comparison data setting section 7? Compare with the specified comparison data, and if there is a discrepancy exceeding the specified range,
Automatically correct MP4 gain.

The logic section 9 controls the switching of the analog data switching section 3 via the buffer 8, and the data comparing section 6
make it work. Furthermore, when digital data is added from the A/D converter 5, the logic section 9 sends this digital data to the output terminal l3 via the line interface section 12. Furthermore, the logic section 9 includes an alarm generation section 11
The alarm is sent to the output terminal 13 via the line interface section 12.

The voltage comparator 10 compares the reference voltages from the reference voltage generators 2l and 2■, and if either of the reference voltages changes,
Send output.

The alarm generating section l1 generates an alarm when the output from the voltage comparator 10 is applied.

Next, the operation of this analog data input circuit will be explained.

Analog data is input from input terminals 1 and 1■ and sent to analog data switching section 3.

The analog data switching section 3 sends out the added analog data under the control of the logic section 9 via the buffer 8. The analog data sent out from the analog data switching unit 3 is added to the AGC-AMP 4. A
The GC-AMP 4 amplifies this analog data using a set gain and applies it to the A/D converter 5. A
The analog data inputted to the /D converter 5 is converted into digital data and outputted to the line from the output terminal 13 via the logic section 9 and the line interface section 12.

On the other hand, the reference voltage generating section 2. constantly generates a reference voltage,
This reference voltage is sent to the voltage comparator 10 and the analog data switching section 3. The analog data switching section 3 is switched under the control of the logic section 9 via the buffer 8, and sends out this reference voltage. The reference voltage sent out from the analog data switching unit 3 is the AGC-AMP 4
The signal is applied to the A/D converter 5 via the . The A/D converter 5 converts this reference voltage into digital data and calculates the data ratio? Send to section 6.

The logic unit 9 controls the switching of the analog data switching unit 3 mentioned above via the buffer 8, and
The data comparison section 6 is operated. The reference voltage converted into digital data by the A/D converter 5 is led to this operating data comparison section 6, and is compared with comparison data arbitrarily set by the comparison data setting section 7, and is converted into digital data within an arbitrary range. If there is any discrepancy, the gain of AGC-AMP 4 is automatically corrected.

By the way, the reference voltage generation section 2■ is the reference voltage generation section 21.
Separately, a reference voltage is generated. The voltage comparator 10 constantly compares the reference voltage from the reference voltage generator 2l and the reference voltage from the reference voltage generator 22. If either of the reference voltages changes, an output is generated in the voltage comparator 10, and an alarm is generated by the alarm generating section 11 at the next stage. This alarm is input to the logic section 9 and transmitted via the line interface section 12 to an output device not shown in FIG. Therefore, it becomes possible to detect errors in analog data on the output device side, resulting in can output new analog data.

Note that the voltage value of the reference voltage can be set arbitrarily, and the number of reference voltage generators and the number of input terminals are not limited.

〔Effect of the invention〕

As explained above, since the present invention can constantly monitor changes in the reference voltage, even if the gain of the conversion means is automatically corrected, incorrect digital data will not be transmitted to the output device, and as a result, correct analog data will be transmitted to the output device. Data can be transmitted.

[Brief explanation of drawings]

FIG. 1 is a functional block diagram of an analog data input device according to an embodiment of the present invention, and FIG. 2 is a functional block diagram showing an example of a conventional analog data input device. 1,,1■...Input terminal 21.2■...Reference voltage generation section 3...Analog data switching section 4...
・＾GC-＾MP 5... A/D converter 6 ・ 7 ・ 8 ・ 9 ・ 10 ・ 1l ・ 12 ・ 13 ・ ・Data comparison section ・Comparison data setting section Logic buffer ・Logic section ・Voltage Comparator, alarm generation section, line interface section, output terminal

Claims (3)

[Claims] (1) When analog data is added, the analog data input circuit sends digital data converted from the analog data to the line via the interface section, which includes a plurality of voltage generating means for generating reference voltages, and the voltage generating means. an alarm means that compares the reference voltages of the reference voltages with each other and generates an alarm due to a change in one reference voltage; a conversion means that amplifies the applied selection signal by a set gain and converts it into digital data; logic means for sending digital data from the means to the interface section, and sending this alarm to the interface section when an alarm occurs in the alarm means; and under the control of the logic means, analog data and voltage generation of 1 switching means for switching a reference voltage from the means to a selection signal; and switching means for converting the digital data into a predetermined setting value when the logic unit is activated and the digital data from the converting means is based on the reference voltage. 1. An analog data input circuit comprising comparing means for comparing and correcting the gain of said converting means when the comparison result exceeds a predetermined range. (2) first and second voltage generating means for generating a reference voltage in an analog data input circuit that converts the analog data and sends the digital data to the line via the interface section when analog data is added; Alarm means for comparing the reference voltages of the first and second voltage generation means and generating an alarm due to a change in either of the reference voltages; and amplifying the applied selection signal by a set gain. converting means for converting into digital data; logic means for sending the digital data from the converting means to the interface section and sending this alarm to the interface section when an alarm occurs in the alarm means; and the logic means. control, the analog data and the first
switching means for switching the reference voltage from the voltage generating means to produce a selection signal; an analog data input circuit, comprising comparison means for comparing the gain of the conversion means with a set value and correcting the gain of the conversion means if the comparison result exceeds a predetermined range. (3) The alarm means for generating an alarm includes a voltage comparator that compares reference voltages from the first and second voltage generation means, and an alarm generation section that generates an alarm based on input from the comparator. The analog data input circuit according to item 2.