Electrical installation
PCD0
26/766 E2
(HB_PCD0 26 766_E2.DOC)
SAIA-Burgess Controls Ltd.
Page 117
Connecting the bus coupler and expansion modules to ground (2) (3)
The bus coupler and the 8 I/O expansion module (8I/O) have a
connecting terminal marked with the ground symbol. To increase
interference immunity this terminal must be connected to ground (or
PE potential) with a conductor which is as short as possible (2.5mm
2
).
For optimum EMC properties the first expansion module on the
right of the bus coupler should be powered via the potential relay
terminal on the bus coupler.
All other modules can also be powered individually.
The contact spring located in the module clamp base is used to divert
EMC interference. This spring provides the connection between the
PCB shield potential and the DIN rail. Do not fit modules without a
contact spring or with a defective contact spring.
Contact springs of the EC and BC bus couplers in the clamp base on
the rear of the housing.
Relaying the power supply (4)
To provide an optimum wiring the power supply can be relayed from
one module to the next. When using modules with digital outputs the
current on each relay terminal must not exceed a specific value. If the
maximum current is exceeded an additional power supply feed must
be provided (see below).
Additional power supply feeds (5)
When relay terminals are used to relay the power supply from one
module to the next the current on each relay terminal must not exceed
a specific value.
Make sure that the load on a terminal does
not exceed Imax = 8A
.
If the maximum current may be exceeded you need to provide
additional power supply feeds.
