KMC Controls XEE-6311 - Manual (Page 6)

– –
–
KMC
XEE–6000
Series
Transformer
Isolation
Transformer
Device A
Device B
24 VAC 120 VAC
24 VAC
24 VAC
KMC Controls
AN0604D Revision B
Tips for connecting 24-volt power
Connecting to controllers
1–20
Grounded transformer secondaries may also become a source of a network
ground loop.
A ground loop occurs in a network when a small voltage potential
exists between two or more “ground” connections. This potential introduces an
unwanted current in a signal path, adding noise to the network and possibly even
damaging equipment. Symptoms of ground loops in KMC controller networks
may include one or more of the following network communication problems:
◆ Misreadings of inputs.
◆ Panels drop off the network.
◆ Multiple attempts required to open data screens.
◆ Unable to pass network points.
◆ Network bulbs illuminate.
Good network planning and wiring practices will avoid most problems with
ground loops and save considerable time and expense. To avoid ground loops,
take care to provide only one electrical path to ground and follow good wiring
practices.
Illustration 7 Powering a full-wave and a half-wave device from a grounded
transformer