Danfoss VLT AQUA Drive Design Manual page 25

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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 (setpoint) is set between 0 and 10 Bar using
a 0-10 volt potentiometer or can be set by a parameter. 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) con-
nected to terminals 50 (+10 V), 53 (input) and 55 (common).
3. Pressure feedback via transmitter (0-10 Bar, 4-20 mA) connec-
ted to terminal 54. Switch S202 behind the Local Control Panel
set to ON (current input).
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MG.20.N4.02 - VLT is a registered Danfoss trademark
2. Introduction to VLT AQUA Drive
2
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