I have a problem with 2 M-bus energy meters and Siemens WZC-P60 signal converter. As long as the WZC-P60 is supplied from the transformer in the rack, the WZC-P60 shows that there is a shot cuircuit on the bus. When I connect an external transformer to the WZC-P60, the meters could be identified and addressed.
What could be the reason for this? Ground loops?
I should add that the M-bus is not gavlanic seperated in the meter so there is an eletrical contact out to the flow sensor i the piping.