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Model BD306 Dual-Input Pump Controller Instruction Manual
7.13.6. Signal Input Conditioning (
Functn
)
The
Function menu is used to select the input-to-output transfer function applied to the input sig-
nal: linear, square root, programmable exponent, or round horizontal tank volume calculation.
The multi-point linearization is part of the linear function selection.
Meters are set up at the factory for linear function with 2-point linearization. The linear function
provides a display that is linear with respect to the input signal.
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Square Root Linearization (
SquArE
)
The square root function can be used to calculate flow measured with a differential pressure
transmitter. The flow rate is proportional to the square root of the differential pressure. Scale
the meter so that the low input signal (e.g. 4 mA) is equal to zero flow and the high input signal
(e.g. 20 mA) is equal to the maximum flow.
Programmable Exponent Linearization (
ProG E
)
The programmable exponent function is used to calculate open-channel flow measured with a
level transmitter in weirs and flumes. The flow rate is proportional to the head height. Scale the
meter so that the low input signal (e.g. 4 mA) is equal to zero flow and the high input signal
(e.g. 20 mA) is equal to the maximum flow. This method works well for all weirs and flumes
that have a simple exponent in the flow calculation formula. For weirs and flumes with complex
exponents it is necessary to use a strapping table and the 32-point linearization of the meter.