K-type thermocouple transmitter
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How to adjust the zero range, and when is it necessary to do so?
In the first image, there is a potentiometer below the white dot on the left side, which is used to adjust the range; on the right side, it’s used to set it to 0, but this value should be adjusted according to the room temperature at that time. The white dot is made of silicone, and it can be removed by picking it off. After making the adjustments, it’s sealed again
0 mV corresponds to room temperature; a millivolt generator is needed to adjust the range
This post was last edited by Pandora on 2017-11-13 at 13:43. See the white glue? It’s just two potentiometers. It’s for zeroing the range; it’s quite difficult to adjust on your own. There is no verification equipment. If you have a device that can input millivolt signals with high precision (the dial shows three decimal places. The standard table must have at least four decimal places). It can be calibrated with reference to the scale table.
Everyone, I’ve installed a new set of thermocouples, and the reading is around 180°C, but the actual temperature is only about 40°C. After checking, I found that the problem lies in the transmitter module. I want to know if it’s possible for me to fix it!
The transmitter is equipped with adjustment potentiometers for zero point and range, which should be adjusted in accordance with the requirements of JJF 1183-2007 \"Calibration Specifications for Temperature Transmitters\".
This is a fixed range that the user cannot adjust. I’ve encountered this situation as well; in the end, I had the manufacturer replace the range.
The displayed temperature is inaccurate; you also need to check whether the range settings of the display instrument or DCS match those of the temperature variable. If they do not match, the displayed value will definitely be incorrect.
Zero-range adjustment and setting are two different concepts; do not confuse them.
0 mV corresponds to room temperature; a millivolt generator is needed to adjust the range
I have a question: I don’t understand why 0 mV corresponds to room temperature