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一、引言目前在化工企业广泛使用的电子自动平衡电桥与电位差计是非防爆仪表。这些仪表与各种热电阻及热电偶配套组成温度测量系统,若用于具有爆炸性混合物(可燃性气体蒸汽与空气形成的爆炸性混合物)的环境时,必须采取可靠的防爆措施。目前较多采用的措施是选用防爆型(其防爆型式为隔爆型)热电阻及热电偶与电桥、电位差计配套组成温度测量系统。但此类系统在实际使用中存在一些不可避免的缺点,给仪表的使用和维修带来了不少麻烦。如处理一次元件故障时必须停掉仪表电源,而多点测温仪表的停电使其它测量点的检测也不能进行,给工艺操
I. Introduction Currently widely used in chemical companies electronic balance bridge and potentiometer is non-explosion-proof instruments. These gauges, combined with a wide range of RTDs and thermocouples, make up a temperature measurement system that must be reliably flame-proofed for use in an environment with an explosive mixture of an explosive mixture of flammable gas vapors and air. At present more measures are used explosion-proof type (its explosion-proof type explosion-proof type) thermal resistance and thermocouple and bridge, potentiometer supporting temperature measurement system components. However, there are some unavoidable disadvantages of such systems in actual use, which bring a lot of troubles to the use and maintenance of the instrument. Such as processing a component failure must stop the meter power supply, and multi-point temperature measurement instrument power outages to other measurement points can not be detected, to the process of operation