Precision Digital PD6060 - Manual (Page 74)

Model PD6060 Dual-Input Process Meter Instruction Manual
74
Signal Input Conditioning (Functn)
The Function menu is used to select the input-to-output transfer function
applied to the input signal: 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.
Square Root Linearization (Square)
The square root function is 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.