ABB RLM01 Inbetriebnahmeanweisungen Seite 8

Description of functions
8
The first data coming in over line A or line B with a correct telegram start are routed
to terminal M. With simultaneity, either line A or line B is selected at random. Testing
and selection is always based on the first character. In the case of a telegram start
with error on A, the control logic switches to the redundant line B. The same proce-
dure applies vice-versa for line B.
Data coming in over line M with a correct telegram start are routed in parallel to the
two terminals A and B. The test for data is always based on the first character. In the
case of a telegram start with error, the control logic does not output any data to A
and B.
Either a single or a redundant power supply with 24 VDC is possible. The distribution
of load across L1+ and L2+ is based on the level of the voltages applied. If a voltage
source fails, the switch to the redundant supply source is made without interruption.
A monitoring logic circuit tests whether both voltages are present.
3BDD011600R05