Thermocouple technical issues
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I’ve just started working with automation. We ordered a batch of thermocouples here. The order specifications were clear: the thermocouples were to have ranges of 150°C, 400°C, and 800°C. However, the thermocouples delivered by the manufacturer all have an 800°C range. Since the signals from these thermocouples need to be fed into the DCS system, will having all of them with the same range affect the DCS signals?
It depends on the requirements of your manufacturing process. Generally speaking, if the temperature accuracy requirement isn’t extremely high, a 800 model will suffice. However, different thermocouples have varying degrees of accuracy in measuring temperature; usually, the accuracy is highest in the middle range of the measurement scale, while the values at the extremes of that range exhibit greater errors. As for the difference in connecting them to DCS, there’s no difference; it’s all the same. However, you need to set the models of these thermocouples in DCS. By the way, for a temperature measurement of 150 degrees, a thermistor should be used; thermocouples may exhibit significant errors at this temperature range. The reason you all make it the same is probably to facilitate the use of spare parts and maintenance replacements
It can be used, but its accuracy is a bit low.
For 150,400, use a thermal resistor; thermocouples offer higher measurement accuracy in high-temperature areas
Agree with what was said on the fourth floor. It can be displayed, but the precision isn’t up to standard; it’s basically useless, right? Sigh
It will certainly affect the DCS signal; it is best to choose a range of 1/3 to 2/3, and it is advisable to refer to the manufacturer’s specifications for this range
As long as the model is correct, it can be used across various range levels; for 150 degrees, a resistor is recommended.
Thank you all for your helpful answers; I salute you all here! !
The temperature measurement range of a thermocouple depends on its calibration class, while the display range can be set via the DCS – as long as the setting range of the DCS falls within the normal measurement range of that particular calibration class of thermocouple.
A thermocouple has only a certain measurement range, which is determined by the electrode material of the thermocouple; its readings change linearly within that range. It doesn’t have ranges such as 150°C and 400°C
It’s a problem with your order – thermocouples don’t have such low values. For 150, CU50 or PT100 thermal resistors should be used. However, if the accuracy requirements aren’t extremely strict, it’s fine to adjust the range in the DCS configuration for use