PV not show while Pt100 connected. what could be the problem and how to solve this
1 check your sensor first its specification. Then check with a multimeter for resistance.
2 . If step 1 confirms then check the sensor selection on the controller.
3 set to PT 100 and then check temperature range high and low.
check PT100 resistance with multimeter, if OK then check wiring connected on correct terminal diagram as per mention at controller, if OK then check configuration parameter,
I was curious about the word STOP in the upper display in the photograph. I have never worked with the MA900 controller, so these comments are interpretations of the manual (at the link below),
On page 6, the flow diagram shows a RUN mode and a STOP mode.
RUN/STOP mode does not appear to be associated with typical setpoint programming ramp/soak run/hold/stop because this controller has no provision for entering ramp/soak values.
There is a ‘Scan display’ function (page 16) that uses the CH key to start/stop the channel value scan, so RUN/STOP is not likely the same function.
The closest I could find to a definition of run/stop mode is on page 16, right column:
Conditions when changed to STOP mode:
• Control:OFF
• Alarm: OFF
• AT: Cancel (The PID constants are not updated) (Autotune)
It is not clear what the control output state is for STOP mode. It might be equivalent to conventional “manual” mode which is an output state maintained at the moment the Stop mode is initiated, or it might be a failsafe mode, where outputs go to a given pre-defined state.
If the control output is OFF in the STOP mode, then it might be that the issue might not be an RTD issue, it might be that the controller is not controlling because the controller is in the STOP mode as shown in the photo.
If the problem is STOP mode, put the controller into RUN mode to get it to control the temperature.
If it is truly an RTD issue, then there is likely an displayed error code that reflects a problem with an RTD input.
Or the control loop might be looking at the wrong RTD, given that there are four RTD inputs; a configuration issue.
My experience with new installations having an RTD problem is mis-wiring. For a 3-wire RTD with with 3 wires and 3 terminals there are 6 possible wiring combinations, only 2 of which will operate properly, the other 4 won’t. High probability of incorrect wiring.