ProtEX PD8-6080/PD8-6081 Explosion-Proof Modbus
®
Scanner Instruction Manual
64
Square Root Function Menu (
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 scanner 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 Function Menu (
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 scanner 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 scanner.
