Zener type intrinsically safe analog signal conversion digital signal circuit

Abstract

The invention provides a zener type intrinsically safe analog-to-digital signal conversion circuit. The zener type intrinsically safe analog-to-digital signal conversion circuit comprises an analog-to-digital conversion integrated circuit, a low-loss voltage-stabilizing circuit, an overload protection circuit, an integration circuit, a power line safe grid circuit, a data line safe grid circuit, a clock line safe grid circuit and a control mainboard, wherein the control mainboard comprises a mainboard power supply and a CPU processor; the CUP processor carries out data transmission with the analog-to-digital conversion integrated circuit respectively through the data line safe grid circuit and the clock line safe grid circuit; the mainboard power supply is electrically connected with the analog-to-digital conversion integrated circuit successively through the power line safe grid circuit and the low-loss voltage-stabilizing circuit; the low-loss voltage-stabilizing circuit is connected to the analog-to-digital conversion integrated circuit through the overload protection circuit; and the clock line safe grid circuit is connected to the analog-to-digital conversion integrated circuit through the integration circuit. According to the invention, the safe grid circuits are placed after the analog-to-digital conversion integrated circuit, such that the input end of the analog-to-digital conversion circuit is prevented from being affected by safe grid leakage currents and the metering accuracy is improved.

Description

technical field [0001] The invention relates to the field of analog-to-digital conversion circuit design, in particular to a Zener type intrinsically safe analog signal conversion digital signal circuit applied to the danger zone of an explosion-proof weighing instrument. Background technique [0002] The traditional "converting analog electrical signal to digital electrical signal circuit" (hereinafter referred to as: analog-to-digital conversion circuit) cannot be used in dangerous places with explosion-proof requirements, and it is necessary to add a compliance sensor between the strain gauge sensor and the analog-to-digital conversion circuit. safety fence. However, there are several problems with this combination: [0003] 1) Ordinary safety barriers generally have the problem of leakage current. For strain gauge sensors, because their output signals are relatively weak, they belong to the mV level; if the ordinary safety barrier is placed at the signal input end of th...

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Problems solved by technology

[0003] 1) Ordinary safety barriers generally have the problem of leakage current. For strain gauge sensors, because their output signals are relatively weak, they belong to the mV level; if the ordinary safety barrier is placed at the signal input end of the analog-to-digital conversion circuit at this time The signal line used to connect the strain gauge sensor before will cause the signal to drift due to the leakage current of the ordinary safety barrier

[0004] 2) Since the safety barrier and the analog-to-digital conversion circuit are separate components, the temperature coefficients of the two are not consistent, which will bring additional electrical noise

[0005] 3) The circuit designed in combination mode needs to add multiple safety barriers, which increases the cost of circuit design and increases the maintenance cost

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