The temperature of the thermal resistor fluctuates greatly
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There is a thermal resistor on site; when measured with a multimeter, its resistance is 121.4 ohms, which is quite stable. The terminals are secure as well, but the temperature displayed on the DCS keeps fluctuating. The safety barrier of the system was replaced, yet the issue persists. What is the reason for this?
Check the signal transmission lines; there’s probably some damage causing interference
Simply connect a thermoresistor to the grounded DCS input terminal. If the reading doesn’t fluctuate, the problem lies in the wiring or the thermoresistor; otherwise, check the DCS display terminal
Is it available with temperature change? Check it. Is the insulation resistance acceptable? Measure it.
Measure the resistance on the wiring side of the rack to see if it remains stable. If it does, try switching to another channel.
This post was last edited by cqdfwy on 2022-6-24 at 11:44. Remove the field thermistor from its mounting sleeve and connect it to the system to see if the displayed temperature still fluctuates erratically; this will help determine whether the insulation of the thermistor is satisfactory.
Check if the silicone oil inside has dried out
The resistance measurement in the cabinet room also showed an abnormal value; I replaced the cable, and things returned to normal after that.
The resistance measurement in the cabinet room also showed an abnormal value; I replaced the cable, and things returned to normal after that.