Why does the PT100 value keep fluctuating when connected to a digital display?
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This post was last edited by chenyan4244 on 2016-7-18 at 10:40. They are all from Tiankang; the readings don’t fluctuate constantly – they may remain stable for minutes or hours, but at other times they keep changing, with the temperature varying by several degrees Celsius in just one second. When using a multimeter to measure the resistance value, it remains fairly stable, with fluctuations of around 0.1–0.2. It was thought that the issue might lie with the digital display, so a new one was tried, but it still didn’t work. The interference resistance setting of the digital display was adjusted to its maximum level, yet still no improvement was seen. A new thermistor was also tried, with no success. The wire connecting the devices is only three or four meters long, and testing it showed no problems. I’d like to ask the experts how to solve this problem
When observing the fluctuations, check whether there is any vibration at the device; if so, reconnect the wires. Also, give the original factory connection wires a tug to check them as well
The wire ends were reconnected a long time ago; the reaction vessel must be experiencing vibrations constantly
Then check out the craftsmanship! Is it something like the material vaporizing? The substance that was originally measured as a liquid turns into a gas. I’ve encountered this; as long as the manufacturing process is stable, it’s fine
Not really. It’s the same batch of material; under conditions of stable reaction, temperature changes during cooling or heating are normal. However, temperature changes of several degrees Celsius in just one second can only be considered as abnormal fluctuations, which is not normal
Make sure the wire is fine; if there’s no issue with the manufacturing process, try using a new one! There isn’t much money
Check the grounding and temperature changes; replace the safety barrier with another one. Finally, replace the thermistor as well – go through each item one by one to identify the issue
1 pt100 three-wire system; the scale markings on the digital display are also of the three-wire type. 726 makes it much easier to handle.
It’s not temperature-controlled; there’s no safety barrier, and it’s not connected to a DCS system – instead, the data is displayed directly on a digital meter. This is how small factories usually operate
It is indeed third-tier. So what should I do about it? Please tell me; it’s been bothering me all day
The thermistor and display gauge have been replaced, but the problem persists; even the wiring has been changed. If it still doesn’t work, then it’s necessary to carefully check whether there are any issues with the manufacturing process.....