I have a system using a Siemen's Analog Input Module AI 8xU/R/RTD/TC HF (6ES7531-7PF00-0AB0) that has a PTC attached to one of the input channels.
The manual for the module is here, and the relevant section appears to be on page 26, "Using PTC Resistors". However, I can't translate the (English) language of the manual into something that actually makes sense to me! These are the relevant parts of that page:
How do these two figures translate into concepts like:
- The temperature is OK (lack of Alarm/Warning)
- The temperature is Too High (an Alarm)
- The temperature is Not good, but not bad (IE a warning)
(I can understand Short circuit well enough .. lol)