Danfoss VLT AutomationDrive FC 300 Design Manual page 35

FC 300 Design Guide
Example of Process PID Control
The following is an example of a Process PID Control used in a ventilation system:
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 con-
stant, for which purpose the Process Control is to
be used.
The control is of the inverse type, which means
that when the temperature increases, the venti-
lation speed is increased as well, so as to generate
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 trans-
mitter.
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).
Example of Process PID Control set-up
Introduction to FC 300
®
MG.33.B8.02 - VLT is a registered Danfoss trademark
35