Hello, As the best I can see you monitor temperature. I had similar issue before on another monitoring system. I worked on an injection moulding machine. The trend was ok for 3 - 4 moths after the installation. Last week the company reported they are having some peak on one of the barrel temperature monitoring. Injection moulding machines have a lot of moving units. - Trend the income value in TIA portal so you can figure out is it a real peak in your signal or just a random issue. - Do a double check on your probe condition - Do a double check on your cable - If the machine do a lot of movement try to figure out which movment is causing interference - If the cable is not shielded correctly it is a possibility can pickup some random signals which could cause interference on the actual reading - If your probe is resistance related buy an analogu multimeter " NO DIGITAL " and put it on your probe. Analogue multimeter is more capable to show peaks. Good luck.