Why do PCD3.Wxxx input modules placed on an extension modules PCD3.Cxxx not work properly?

FAQ #100054

 

Symptom
Analogue input modules PCD3.Wxxx placed on or after a PCD3.C200 do not work correctly. They give unstable, changing or/and wrong values. If placed on a high address, it isn't possible to access the I/Os.

Reason
This phenomenon could be caused by a missing power supply or if the current consumption of the I/O modules exceeds the maximum supply of the extension module.
It could also be that the 24V power supply of the PCD3.C200 is interrupted by a missing jumper (the PCD3.C200 has a jumper inside to activate the 24 V power supply). If this jumper is missing the PCD3.C200 is acting as a PCD3.C100!

Solution
First verify whether the maximum current for your I/O constellation on the LIO is sufficient. This can be done by

• the "Useful Excel sheet" to calculate the power consumption which can be found in the PCD3.Mxxx section of the support site
• or with the Device Configurator (from PG5 1.4.300 or PG5 2.0)

If the power consumption is not exceeded, open the cover of the PCD3.C200 and check if the jumper situated in the top right corner of the print is set.