Danfoss VLT AutomationDrive FC 300 Design Manual page 34

3. Introduction to FC 300
3.3.4. Example of Process PID Control
The following is an example of a Process PID Control used in a ventilation system:
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In a ventilation system, the temperature is to be settable from - 5 - 35°
C with a potentiometer of 0-10 Volt. The set temperature must be kept
constant, for which purpose the Process Control is to be used.
The control is of the inverse type, which means that when the tempera-
ture increases, the ventilation speed is increased as well, so as to gen-
erate more air. When the temperature drops, the speed is reduced. The
transmitter used is a temperature sensor with a working range of -10-40°
C, 4-20 mA. Min. / Max. speed 300 / 1500 RPM.
NB!
The example shows a two-wire transmitter.
1. Start/Stop via switch connected to terminal 18.
2. Temperature reference via potentiometer (-5-35°C, 0-10 VDC) connected to terminal 53.
3. Temperature feedback via transmitter (-10-40°C, 4-20 mA) connected to terminal 54. Switch S202 set to ON (current input).
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FC 300 Design Guide