54
Figure 5�10 – DDC - electric supply
DDC electric supply from external transformer
LEGEND
DDC
Direct Digital Control
AL
supply 4 poles connector
1
clamp and wire for 24 Vac supply
2
clamp and wire for 0 Vac supply
3
clamp and wire for ground contact
(required connection)
DDCTR safety transformer
- (230/24 Vac
50/60 Hz)
If the CAN BUS cable has already been connected to the DDC (next procedure "3) How
to connect the Direct Digital Controller (DDC) to the appliance"), take care with the 4
mm CAN BUS cable shielding eyelet (or two eyelets): use the retainer screw next to
the CAN BUS socket (bottom right) to secure the eyelet (or both eyelets) as shown in
Figure 5.13 Connection from CAN BUS to connector P8
→
57.
The DDC is equipped with a backup battery which retains the memory settings in case
of power failure. The battery has a service life of around 7 years, after which it must
be replaced by the Robur TAC.
3) How to connect the Direct Digital Controller (DDC) to the appliance
The appliance and the DDC communicate with each other via the CAN network (
data
network
), which is characterised by a number of
nodes
, connected by the
CAN BUS
cable
.
By a
node
of the
data network
we mean any device (DDC, appliance or individual mo-
dule) connected to it. Each network consists of 2
terminal nodes
and, if required, a cer-
tain number of
intermediate nodes
. A device is considered to be a
terminal
node when
it is connected to only one other device. A device is considered to be an
intermedia-
te
node when it is connected to two other devices. Appliances, individual modules
and DDC's may act equally as terminal or intermediate nodes. See Figure 5.11 CAN
network
→
55.
