Anti-interference multi-channel analog sampling circuit and method

Abstract

The present invention discloses an anti-interference multi-channel analog sampling circuit and method. The anti-interference multi-channel analog sampling circuit comprises a controller, an A / D converter, M SPI chips, and N sensors. The data output end DoutaM of the Mth SPI chip is connected to the verification signal input terminal Douta of the controller. The M SPI chips are subjected to cascade connection to form a daisy chain sampling structure, and thus the sampling of any sensor can be controlled. An isolation chip is arranged between a first SPI chip and the controller. An isolation chip is arranged between the A / D converter and the controller. The isolation chips are ADuM1411 chips. The SPI chips are ADG739 chips. AD7793 is employed by the A / D converter. The anti-interference multi-channel analog sampling circuit and method are easy to implement, and the anti-interference effect is prominent.

Description

technical field [0001] The invention belongs to the field of industrial automatic control, monitoring system and process control, and relates to an anti-interference multi-channel analog quantity sampling circuit and method. Background technique [0002] In the industrial production process automation system, the industrial site needs to monitor various on-site physical quantities such as voltage, current, temperature, pressure, stress, and flow. Considering the cost and applicability, the I / O board and signal transmission of DCS are related to the signal. The acquisition part adopts the technology of multi-channel analog acquisition. When collecting temperature, the industry usually uses temperature sensors such as thermal resistance (RTD) or thermocouple (TC) to convert the temperature into an electrical signal, and then use a dedicated temperature detection system to detect and control the temperature. In temperature control, the accuracy and reliability of temperature d...

AI Technical Summary

Problems solved by technology

[0004] At present, the ADCs of our company's fieldbus-type multi-channel temperature acquisition controllers use SPI-type chips as high-speed analog-to-digital converters. All digital signals are transmitted on the SPI communication link. Due to interference noise, Make "1" become "0" and "0" become "1", which affects the performance of the SPI chip, and even the SPI chip cannot work normally

In some special environments, such as thermal power plants and smelting and metallurgical industries, there are many uncertain factors on site, and the signal is easily interfered. No matter from theoretical analysis or experience, the SPI chip has no calibration function, so the anti-interference ability is weak , therefore, it is necessary to design an anti-interference multi-channel analog sampling circuit and method

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