ceilingwalker
Lifetime Supporting Member
Good day all. I have a SLC5/03 with a 1746-NR4 RTD Module. I'm using 100-Ohm RTD's in acid baths. When the calibration tech measured the tanks with his meter, the temperature varies from what the PLC is displaying. I put in a simple ADD instruction to create an offset. The problem is, they will match for about 3-4 hours, then when checked again, the offsets must be removed because with the second check the temps are now out of whack with the calibration device. The device goes to the manufacturer for calibration on an annual basis and was just calibrated 2-months ago. Any suggestions or ideas as to why this is happening? Thanks much.