Pump Control Application
The basic difference between a simple level application and a pump control application
is that
the relays assigned to pump functions are normally in a de-energized state and
are energized when pumping is required.
The HydroRanger I can be programmed to control up to 5 pumps, each in one of the
following ways.
1. fixed roster: (P-8,11,14,17 & 20 = 8)
selected pump relays 1 - 5 always operate in conjunction with their respective
relay setpoints. i.e. relay 1’s operation is always subject to relay 1 setpoints
(P-9 & P-10). Any combination of the selected pumps can be operating at a
time.
2. sequential operation:
• cumulative (P-8,11,14,17 & 20 = 9)
selected pump relays 1 - 5 sequentially rotate through the associated relay
setpoints changing pump/setpoint assignment each time the lead pump is
turned off. The lead pump is defined as the pump responding to the first
on setpoint.
• duty/back-up: (P-8,11,14,17 & 20 = ’9)
similar the to cumulative sequential loop except that only one of the pumps
designated as duty/back-up can be on at a time. This feature is useful in
older installations where the discharge main can not tolerate excessive
pressure. If the lead pump, through wear or blockage, can not keep up with
the inflow, the next pump in sequence will come on and the lead pump will
be turned off. The ON setpoints are generally in close proximity, but the
OFF setpoints must be common for all pumps on the loop.
• ratio: (P8, 11 14 17 & 20 = A9)
assignment of a pump/relay contact to a setpoint parameter is done by ratio of
the logged service hours relative to the allocated ratio as set by parameter
P-24 through P-28. When a pump is required, the pump with the least
amount of service hours (C-24 to 28) is started. When a pump is not
required, the pump with the most hours of service is stopped.
e.g. relay 1,2 and 3 control three pumps by service ratio. It is required that
pump 1 operate 60% of the time, pump 2 operate 10% of the time and
pump 3 operate 30% of the time.
set the relay function : P-8, 11, 14 = dE:A9
set the relay setpoints : P-9/10, 12/13, 15/16
set the P-24, 25, 26 ratios : A-24 = 60, A-25 = 10, A-26 = 30
PL-399 6 – 7
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