AAA86 Posted April 16, 2013 Report Share Posted April 16, 2013 Hi, I have a problem. I have 2 same main boards of the PLC V350-35-TA24 with same HW and SW configuration, but there is a problem. 1 of the PLC is reading the Thermocouple temperature and the other reading constantly -0.1C. I've passed the configuration a lot of times, the boards REVs and etc. it all the same.... there is probably something in the way tha confusing the Thermocouple reading in the main board but i can't find it. Is anyone can help me by providing me a solution or schematics or where the thermocouple is connected to the main board and rhough what devices it going. Thanks in advance. Link to comment Share on other sites More sharing options...
AlexUT Posted April 28, 2013 Report Share Posted April 28, 2013 Hi, 0.1C difference between 2 OPLCs is not a problem. From Datasheet: Resolution is 0.1 C. Cold junction compensation error ±1.5°C maximum. Full-scale error ±0.4% Linearity error ±0.04% Warm-up time ½ hour typically, ±1°C repeatability Everything is in range. So why do you panic and require schematics? It seems useless. Isn't it? My advice is to use it as-is. I see no problem in your configuration. BR Link to comment Share on other sites More sharing options...
MVP 2014 Simon Posted April 28, 2013 MVP 2014 Report Share Posted April 28, 2013 It sounds like one of your thermocouples always reads -0.1C regardless of temperature. As Alex suggests, the scehamtic is not going to tell you much. I would check: * swap thermocouples to ensure they are both working * ensure the thermocouple is connected with the correct polarity * configure another thermocouple input on the same PLC. The most likely problem is a faulty probe, incorrect/faulty wiring or configuration error. If those can be conclusively eliminated, then perhaps there is a faulty input on the PLC, but that is the least likely, based on my experience. Link to comment Share on other sites More sharing options...
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