WattMaster WCC II - Manual (Page 212)

Section 5: Installation Guide
WCC II Operator’s Guide
Operator Interfaces 5-10
System Wiring
The Central Processing Unit (CPU) can communicate with up to
240 satellite controllers via a two-wire communication loop. The
two-wire communication loop should be a twisted pair of 18 gauge
wire and shielded. Stranded wire is recommended to insure a good
connection with the ¼ inch sta-con connectors which are used to
terminate the wires at the CPU and the satellite controllers. The
communication wire does not have to be run from each satellite
controller back to the CPU but rather can be “daisy-chained” which
means only one twisted pair of wires is connected to the CPU. The
maximum allowable length of wire from the CPU to the farthest
satellite is 1500 feet.
Note: A length greater than 1500 feet is allowed under
certain circumstances. Consult the factory for assistance if the
communication loop required for your application will exceed
1500 feet.
The ECC/WCC II system architecture is shown below: