Views: 0 Author: Site Editor Publish Time: 2022-03-31 Origin: Site
When using a thermocouple, the signal does not come from just the junction, but is created along any segment of the thermocouple conductors from the junction to the end of the thermocouple wires. That said, then the accuracy of the signal will be affected by the performance of all of the thermocouple materials used, as well as the temperature changes along its length.
Thermocouple wire is available in Standard Limits, Special Limits or Extension Grade accuracy as defined in ANSI/ASTM E230 (or Class 1 , 2 or 3 in IEC 60584). So let’s say that we have a thermocouple probe made from special accuracy Type T (±0.5C or 0.4%) wire that experiences a temperature change from 370C at the tip to 200C at the connection to an extension cable. To this point your output will meet special limits accuracy. From here you attach a Special Limits of Error cable which will see a temperature change from 200C to 50C. Since both lengths of thermocouple conductor are Special Limits of Error, the output accuracy of your overall measurement will continue to meet the Special Limits of Error.
Now take that example one step further an instead make the extension cable from Extension Grade wire, you now have an overall accuracy that is a combination of Special Limits of Error from 370C to 200C, and Standard Limits of Error between 200C and 50C. If that is acceptable then the Extension Grade wire is fine. But remember one thing, Extension Grade wire is only tested and certified to 200C, any usage higher then that cannot be assumed to meet Standard Limits unless the wire is calibrated and the actual tolerance used in determining the final measurement accuracy.
Yangzhou Fongming Cable Factory can produce thermocouple wires with a wide variety of types, including: K type, KX type, J type, JX type, KCA type, KCB type, T type, TX type, E type, EX type, N type, NX type Type, NC type, SC type, RC type, BX type, L type, LX type.
Fongming Cable Factory, thermocouple wire and extension wire manufacturer.
https://www.fmcable.cn/products.html
