Cable connector measurement

1. Temperature sensing cable type temperature measurement. The temperature sensing cable is placed in parallel with the cable. When the cable temperature exceeds a fixed temperature value, the sensing cable is short-circuited and an alarm signal is sent to the control system. The disadvantages of the ordinary temperature sensing cable are: destructive alarm, fixed alarm temperature, incomplete fault signal, inconvenient system installation and maintenance, and easy damage to the equipment.

2. Thermistor type temperature measurement. The thermistor can be used to measure the cable temperature value, but it is an analog output. It needs to be amplified by the signal and A/D converted to be received. Each thermistor needs independent wiring, the wiring is complicated and the thermistor is easy. Damage and maintenance are large, the sensor does not have self-test function, and it needs to be checked frequently.

3. Infrared sensing temperature measurement. Infrared sensing uses all objects whose temperature is higher than absolute zero to emit infrared radiation energy to the surrounding space. The infrared radiation energy of the object and its distribution according to wavelength have a close relationship with its surface temperature. Therefore, by measuring the infrared energy radiated from the object itself, its surface temperature can be accurately measured.

4. Thermocouple type temperature measurement. The thermocouple transmission signal requires a special compensation line, and the transmission distance should not be too long. It is not suitable for the actual situation where the cable head has a wide distribution surface; the thermistor is usually a platinum resistor, generally requires three-wire transmission and balanced bridge output. The transmission distance should not be too long, and the ability to resist interference is poor.

5. Integrated circuit type temperature measurement. There are many types of integrated circuit type temperature measuring components, among which the current output type components have large internal resistance and are suitable for long-distance transmission. Generally, they are small in size, and can be sealed at the measured point by a thermal conductive silicone which is resistant to corrosion, moisture, and high temperature. The external wiring is led out by two lines to transmit data, but it is greatly affected by electromagnetic force at the measured point.

6. Fiber distributed temperature monitoring. The fiber distributed temperature measurement system is a relatively advanced system. Temperature measurement is accomplished by generating a backward Raman scattering temperature effect by a laser pulse transmitted in the fiber. The latest fiber-optic distributed temperature monitoring system allows fiber loop lengths of up to 12 km with measurement accuracy of ±1 °C.