Thermocouple is a kind of temperature measuring instrument, for measuring temperature has a very important role. With the development of technology, more and more thermocouple is developed and in many areas of a certain application. Although with the development of technology the function of the thermocouple is getting better and better, but the basis of measurement is always not changed. Thermocouple technology parameters, precision grade 1: class I or class ii, nominal diameter: 2 Φ 13, bending diameter: r p 5 d4, nominal pressure, atmospheric pressure, the thermocouple thermal response time: there was a step change in temperature, thermocouple output changes to correspond to the step change of time is called the thermal response time, 50% of the income with the tau zero. 5 said. 6, insulation resistance: when the ambient air temperature is 20 + / - 1. 5 ℃, relative humidity is not more than 80%, the insulation type thermocouple wire pair between the outer casing and insulation resistance value shall comply with the provisions of the table below. 7, the deflection: thermocouple can rate of bending radius should not less than five times the diameter. : 8, thermocouple diameter d ￠5 mm or less, and there are splash proof or waterproof connector products, users in the installation, please note that thermocouple must be equipped with stents and other auxiliary equipment support, increase the stiffness, ensure strong, prevent the junction box rocking back and forth, damage the thermocouple.