Peripheral Electrical Circuit Troubleshooting
Measure the sensor supply voltage using a multimeter (DC setting) and make sure the deviance is ≤±5%. Examine the power supply module and look for oxidation or looseness in the terminals if the voltage is unusual.
Verify signal transmission lines: For digital communication types, use an oscilloscope to examine waveforms for packet loss or high-frequency interference; for analogue signals, measure line resistance (single-core ≤10Ω/m) and make that the shield grounding resistance is ≤4Ω.
To prevent contact resistance drift brought on by slack connections, tighten the terminals at both ends of the sensor completely.
Sensor Hardware Troubleshooting
Static calibration: To replicate the target temperature and compare it with the sensor output, use a constant-temperature reference source (accuracy >0.02%). Calibrate in accordance with JB/T 8622 if the variation is more than the permitted range (usually ±0.2% FS); if calibration is unsuccessful, replace the component.
Visual inspection: Look for carbon accumulation, scaling, or insulation degradation on contact probes; for infrared non-contact varieties, look for lens ageing or blockages.
Temperature-sensing element performance: Measure resistance linearity after disassembly; a platinum resistor is deemed old and has to be replaced with an equivalent component if its linearity deviation is more than ±0.1% FS.
Troubleshooting Operating Conditions and Installation
Insertion depth: In order to prevent temperature field deviations, contact probes must be submerged in the medium at least five times the probe diameter.
Compatibility with operating conditions: Verify that the temperature is within rated limits; look for unusual medium eddy currents or severe electromagnetic interference (from being close to high-power equipment).
Installation stress: Verify if the mounting base has moved as a result of vibration or whether the probe is distorted as a result of overtightening.
Swapping connections during troubleshooting can drastically cut down on the amount of time needed to identify if the problem is with the temperature controller itself, the sensor, or the cabling.
