Index
Chapter 1 Load Control Relay Option Description Page 2
Chapter 2 Load Control Relay Wiring
Page 3
Chapter 3 Load Control Relay Programming Page 4
4
Chapter 3
Load Control Relay Programming
The Class 3000 meter control relay functions are programmed through four
pushbuttons that are located on the meter display board, which is mounted on
the door of the enclosure.
The pushbuttons are labeled “UP”, “DN”, “SELECT”, and “MENU”. These
buttons are also used for locking the meter’s scrolling display. (See the Class
3000 meter installation manual for more information.)
Programming the load control relay consists of four components. First, the high
threshold point is set. This point is the kW (kilowatt) demand, and increments
are in 1kW. When the load exceeds this point, the relay is activated and
closes (or opens) the contact. The default is “0”, where the function is disabled.
Second, the low threshold point is set; this is the point where the relay de-acti-
vates and opens the contact. Default here is also “0”. When HIGH is set at a
number above “0”, LOW must be set between “0” and the HIGH set point.
Third, the ramp (R) duration is selected; this is the time that the load has to
exceed the high set point or fall below the low set point before the relay will
function. This feature prevents unnecessary operation caused by short load
spikes, such as those caused by a motor starting. Default is 30 seconds (set-
table from 15 to 240 seconds).
Finally, the hold (H) duration is set. This function specifies the interval during
which the relay must remain activated once the HIGH setting is exceeded. This
is to prevent frequent starts and stops (such as in an HVAC system), where
damage could occur with “short-cycling”. Default is 60 seconds, settable from
60 to 2400 seconds.
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