Hardware Manual for the PCD3 Series│Document 26/789; Version E 5│31.01.2005
Saia-Burgess
Controls Ltd.
Power supply and connection plan
PCD3.Mxxx0 Classic CPUs and expansion housings
3-14
3
3.8.2 Earthing and connection plan
In the bottom part of the PCD3 module housing there is a shielding and earthing
plate. Together with the shielding and earthing plate in the module holder, this
constitutes the common, large-area ground for all I/O modules and for the external
power supply
When a module is plugged into the module holder, a metal tab on the module housing
creates a reliable multi-point contact to the module carrier concerned.
The zero-potential (Minus pole) of the 24 V supply is connected to the Minus terminal
of the supply. This should be connected to the earthing bar with the shortest possible
wire (< 25 cm) of 1.5 mm
2
. The same applies to the Minus connection to the PCD3.
F1xx or the interrupt terminal.
Any shielding of analogue signals or communication cables should also be brought to
the same earth potential, either via a Minus terminal or via the earthing bar.
All Minus connections are linked internally. For problem-free operation, these
connections should be reinforced externally with short wires of 1.5 mm
2
.
0V +24VDC
2.5 mm
2
Earthing bar
2.5 mm
2
W
...
I..
.
O
...
