Danfoss VLT AQUA Drive Design Manual page 25

VLT ® AQUA Drive Design Guide
2.9.3. Example of Closed-loop PID Control
The following is an example of a closed-loop control for a booster pump application:
In a water distribution system, the pressure is to be maintained at a constant value. The desired
pressure is set between 0 and 10 Bar using a 0-10 volt potentiometer. The pressure sensor has
a range of 0 to 10 Bar and uses a two-wire transmitter to provide a 4-20 mA signal. The output
frequency range of the drive is 10 to 50 Hz.
1. Start/Stop via switch connected between
terminals 12 (+24 V) and 18.
2. Pressure reference via a potentiometer
(0-10 Bar, 0-10 V) connected to terminals
50 (+10 V), 53 (input) and 55 (common).
3. Pressure feedback via transmitter (0-10
Bar, 4-20 mA) connected to terminal 54.
Switch S202 behind the local control panel
set to ON (current input).
MG.20.N2.22 - VLT ® is a registered Danfoss trademark.
2. Introduction to the VLT AQUA Drive
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