PCD3.F27x and PCD2.F27xx M-Bus is not always short cut protected!
FAQ #101870
Those M-Bus cards have a short-cut protection on the bus but when the CPU isn't anymore power supplied and the F27x(x) card still has 24 V supply there is no short cut protection anymore!
Reason:
The 36 Volts from the M-Bus will destroy some components on the concerned serial port of the card!
Solution:
Use the same power supply for the CPU as for the PCDx.F27x(x) card or if for some reason a different power supply has to be used be aware that in case the CPU isn't power supplied that the M-Bus is NOT short-circuited!
Categories
PCD3 / Fxxx
Last update: 28.05.2015 11:39
First release: 22.10.2013 15:28
Views: 1268
