A Discussion on the Necessity of Anti-Interference Measures for Infrared Thermometers
During the operation of infrared thermometers, interference of varying magnitudes is inevitable, and the intensity of interference differs across various application scenarios. This phenomenon creates numerous troubles for applications in many fields. Therefore, anti-interference measures for infrared thermometers and solutions for suppressing interference under severe interference conditions constitute another key research topic apart from instrument design and development.
When confronted with interference, troubleshooting can be difficult, and users may fail to identify interference as the root cause of faults. Accordingly, if an infrared thermometer malfunctions in environments with strong electromagnetic waves, after ruling out defects within the instrument itself, electromagnetic interference (EMI) should be regarded as the primary suspect.
A practical case is as follows: A steel forging customer purchased nine thermometers from our company. Shortly after commissioning, the customer reported a failure on one unit. Unable to locate the cause on their own, the customer returned the infrared thermometer to our factory for repair. Our technical service department carried out a full inspection and confirmed the instrument was in normal working condition. The thermometer was sent back to the customer, but the fault persisted after reinstallation and testing. Through telephone communication, we suspected that on-site interference was the culprit. Our company dispatched a technician to the site. Upon arrival, the technician first detected that the induced voltage on the thermometer housing reached as high as 20 V, and induced voltage exceeding 20 V was also measured on the iron components of other equipment. High-voltage and high-frequency equipment was installed nearby. It was inferred that the thermometer picked up heavy interference from surrounding equipment via its mounting bracket.
The technician promptly took measures to block the interference propagation path between the infrared thermometer and other equipment: rubber gaskets were fitted between the infrared thermometer and its mounting bracket, and the electrical connection between the circuit board and the housing was disconnected. After reassembly and power-on testing, the instrument worked perfectly and the fault was eliminated. The same modification was applied to the remaining fault-free thermometers. The customer has maintained trouble-free operation ever since.
It can be concluded that external interference exerts a substantial impact on infrared thermometers. In some cases, interference only distorts measured data during operation; in severe circumstances, it may even cause permanent damage to the instrument.
