User guide

VEGACOM 557 Profibus DP 21
Switch adjustments on VEGACOM 557
Hook switches additional board
The hook switches are used to switch on the
bus terminator resistors.
Switch positions
1
2
1
2
Hook switch closed:
Bus terminator "On"
Hook switch open:
Bus terminator "Off"
VEGACOM 557 PLC
Both hook switches are
closed
VEGACOM 557
VEGACOM 557
PLC
Both hook switches Both hook switches
closed open open closed
Example 1:
If a VEGACOM 557 is connected to a PLC,
both hook switches have to be closed (bus
terminator ON).
Example 2:
If several VEGACOM 557 are connected to a
PLC, both hook switches have to be closed
on VEGACOMs located at the beginning and
end of the connecting line, and open on
VEGACOM 557s located in between.