Main board for thermometer and thermocouple precision correcting method

Abstract

The invention relates to a main board for a thermometer and a thermocouple precision correcting method; the main board comprises a main control circuit consisting of a microprocessor, a dial-up input circuit, an interface circuit with at least two slots and a thermocouple sampling circuit; the invention controls the line structure of the sampling circuit with an A / D conversion circuit, reduces the line interference between digital and analog circuits, adds a zero calibration compensation circuit on the front end of the A / D conversion circuit and improves the accuracy of temperature measurement; the invention has the benefits that a bus-type interface circuit is adopted, and a plurality of interface circuit sockets are arranged to realize the extendibility of functions; the A / D conversion circuit is connected with the control end of the analog circuit, thereby reducing the connecting lines between the digital and the analog circuits, reducing the interference of the analog circuit to the digital circuit, and improving the work reliability; and the invention adds the zero calibration compensation circuit, so that when a zero point tends to be negative, the adjustment is very convenient, thereby preventing nonlinear zero-crossing error, and improving the accuracy of temperature measurement.

Description

technical field [0001] The invention belongs to a thermal engineering temperature measuring device for a metallurgical furnace, in particular to a main board for a temperature measuring instrument and a method for correcting the accuracy of a thermocouple. Background technique [0002] Due to the complex working conditions of the current smelting metal melt thermometer, the thermometer used must be easy to operate, stable and reliable; and the current thermometer often needs to set parameters, and the parameter setting adopts the method of row Type multi-position dial, needs to open the case to operate on the main board, which is neither convenient nor safe, and the interface circuit of the main board has no expansion function. With the advancement of technology, functions need to be continuously added, so the interface circuit on the main board should meet expansion needs. And the thermocouple measurement accuracy calibration of the current motherboard still uses the tradi...

AI Technical Summary

Problems solved by technology

[0002] Due to the complex working conditions of the current smelting metal melt thermometer, the thermometer used must be easy to operate, stable and reliable; and the current thermometer often needs to set parameters, and the parameter setting adopts the method of row Type multi-position dial, needs to open the case to operate on the main board, which is neither convenient nor safe, and the interface circuit of the main board has no expansion function. With the advancement of technology, functions need to be continuously added, so the interface circuit on the main board should meet expansion needs

And the thermocouple measurement accuracy calibration of the current motherboard still uses the traditional analog circuit calibration. During the calibration, the potentiometer of the control circuit in the motherboard needs to be adjusted to calibrate. Due to vibration during use, the resistance value of the potentiometer will change slightly. Since this small change changes the correction potential, measurement errors occur and affect the measurement accuracy of temperature measurement

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