6 ELECTRICAL INSTALLATION
44
Figure 6�16 – Wiring diagram for hooking up the Wilo variable rate pump powered by the unit
Wiring diagram for hooking up the Wilo variable rate pump powered by the unit
6�4 TYPE B (DDC)
This paragraph illustrates the operations to be performed when one or more appliances are connected to a Direct Digital
Controller (DDC). In particular:
1.
What is the CAN BUS cable.
2.
How to connect the CAN BUS cable to the appliance's electronic board
3.
How to connect the CAN BUS cable to the DDC.
4.
How to connect the DDC.
5.
How to connect the plant water circulation pump.
For specific information regarding the DDC, refer to the specific manuals supplied with it.
The appliance and the DDC communicate with each other via a CAN bus network.
The CAN bus network is characterized by a series of elements (appliances or DDCs) called nodes, connected to each other by a three-
wire cable. The nodes are of two types: terminal nodes and intermediate nodes.
▶
Terminal nodes are appliances or DDCs that are connected to one other element only.
▶
Intermediate nodes are appliances or DDCs that are connected to two other elements.
The diagram in Figure 6.8 p. 36 gives an example of a CAN BUS network: 3 appliances are connected to each other and to 1
DDC. Appliance D and the DDC (A) are terminal nodes, while appliances C and B are intermediate nodes as they are connected to 2
elements.
It is possible to place one DDC at any point of the CAN bus network: appliances and DDCs may act equally as terminal or
intermediate nodes. One DDC can control and monitor up to 16 appliances. If there are more than 16 appliances on the
network, it is necessary to connect more than one DDC on the same network, up to a maximum of 3.
What is the CAN BUS cable
The cable to be used must be suitable for CAN BUS applications.
Table 6.2 p. 36 gives details of some types of CAN bus cable, grouped according to the maximum distance covered by each single
type.
For overall distances to cover of ≤200 m and networks with a maximum of 6 nodes (a typical example: up to 5 units + 1 DDC)
a simple shielded cable 3x0.75 mm may be used.
LEGEND
PM
Hot water circulation pump (primary
circuit)
MA
Unit terminal block
Pump signal 0-10V wire colours
brown connect to -ve
white connect to +ve
black isolate
blue isolate
Summary of Contents for LCGHP
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