Problem with Pt100 measurement
I'm having trouble with a Pt100 measurement.
I'm using a PM554 PLC with an AX522 I/O module. I wired the Pt100 as shown in the user's manual (- to 2.0, + to 2.1 and return to 1.0). I also configured channels 0 and 1 (as indicated on the manual) to read Pt100 3-WIRE -50.0...400.0°C. I'm taking the reading on the PLC from channel 1.
However, when reading the INT value, I get a very low number (equivalent of -44°C), even though I'm currently at approximately 25°C.
I'm not sure if this is a scaling problem. I've programmed the reading of the INT value to be scaled to a REAL by using a 0 to 27648 scale, according to the manual (see attached image).
What could be causing this? I already changed the Pt100 and have the same problem.
Voted best answer
I could suggest you to look in the help for AX522 -> measuring ranges.
When the channel is configured for Pt100, then the decimal value (INT) for the channel is -500...4000 for normal range.
I'm not using LIN_TRAFO, but I guess in your case IN_MIN=-500 and IN_MAX=4000 will make things happen, in case of correct electrical connection.
3-wire sensors require 2 channels !