Analog quantity conditioning and distributing device with high precision and all-digital calibration

A distribution device and analog quantity technology, which is applied in the direction of adjusting electric variables, control/regulation systems, instruments, etc., can solve problems such as poor reliability, low efficiency, and large errors, and achieve high production efficiency, avoid human errors, and small temperature coefficients Effect

CN102929321AActive Publication Date: 2013-02-13CHINA TECHENERGY +1
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Patent Information

Authority / Receiving Office
CN · China
Patent Type
Applications(China)
Current Assignee / Owner
Publication Date
2013-02-13

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Abstract

The invention discloses an analog quantity conditioning and distributing device with high precision and all-digital calibration, which comprises an instrumentation amplifier, an isolation amplifier, a verification module and an output drive module, wherein the instrumentation amplifier is used for receiving and treating field signals; the isolation amplifier is used for receiving the field signals processed by the instrumentation amplifier and then performing isolation output on the field signals; the verification module is used for receiving and verifying the signals output by the isolation amplifier; the output drive module is used for receiving the signals from the verification module and outputting the signals to a corresponding system; the verification module is connected with a general calibration device which is used for verifying the field signals output by the verification module; the general calibration device comprises an upper computer controlling the verification process and a calibration instrument controlled by the upper computer to generate standard voltage and current signals and transferring the standard voltage and current signals to the verification module; the upper computer is connected with the verification module through an SPI (serial peripheral interface); and the output drive module is connected with the calibration instrument. According to the invention, a digital potentiometer is adopted to replace a mechanical potentiometer, and the digital potentiometer is operated to change value of resistance through the SPI, so that detuning and linear error of the analog quantity conditioning and distributing device can be eliminated.
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Description

technical field

[0001] The invention relates to the field of signal acquisition, in particular to an analog quantity acquisition, conditioning and distribution device for acquiring and distributing analog signals and realizing full digital calibration. Background technique

[0002] In many industrial sites, when different systems are connected, it is hoped that the signals of both parties will not affect each other. In particular, the system failure of one party will not damage the normal operation of the other party. In this case, it is usually necessary to isolate the signal before connecting it. At the same time, signal isolation can also eliminate the impact of ground loops. The main function of the analog signal conditioning and distribution device is signal isolation and signal distribution, and it is used in occasions where on-site signals need to be transmitted to multiple different systems. The input of the analog signal conditioning distribution device is a 0~20m...

Examples

Embodiment 1

[0024] Example 1: In the actual inspection, when the field transmitter sends a 0~20mA current signal, it is converted into a 0~5V differential voltage signal through the 250Ω sampling resistor R of the instrument amplifier; or the field transmitter sends 0~5V When the voltage is input, the differential voltage signal becomes a 0~5V single-ended voltage signal through the instrumentation amplifier TA with a gain of 1. The 0~5V voltage signal is isolated from the input and output through the isolation amplifier (U1~U4). The offset error and gain error of the voltage signal after isolation are adjusted by the universal calibration device of the present invention to ensure the accuracy of the output voltage signal, and the final output voltage signal is output 0~20mA through the voltage-current conversion chip of the output drive module (where the effective value is 4~20mA) the current signal is output to the corresponding system. When calibrating, the calibrator of the universal ...