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Figure 2. 9212 Control/Display Unit
System Operation
Control Panel Settings &
Displays
KW Demand Limit (1):
This indicator displays user-set
kilowatt demand limit in .5 KW increments. The value may
be changed from month-to-month depending on sea-
sonal energy use requirements. Typical residential set-
ting ranges are given in Table 2.
KW Demand Actual (2):
This indicator displays total
household demand in .1 KW increments, which includes
both controlled and uncontrolled loads. Actual KW
demand may be displayed as
Instantaneous
,
Average
or
Peak
, depending upon the desired display mode. See
display key (13).
Relay Unit
The Relay Unit, normally mounted near the load center,
contains up to eight power relays, capable of switching
16 electrical circuits, which turn the loads controlled by
the 9212 on and off. These relays get their commands to
turn on and off from the computer in the Control/Display
Unit by means of the connecting control cable shown in
Figure 3 on page 15.
Current Transformers
Two Current Transformers, usually mounted inside the
load center, monitor total electrical load. They tell the
computer in the Control/Display Unit how much
electricity you are using for all loads, not just those
controlled by the 9212. By monitoring the total load,
controlled loads may be turned on and off to keep total
demand below the limit you set.
Figure 2 shows the front panel of the Control/Display
Unit. Each indicator and key serves a specific purpose
in providing you with the necessary information and
control needed to minimize peak energy usage. Each of
these indicators and keys have been numbered and are
described on the following pages.