Danfoss VLT Series Design Manual page 34

2. Introduction to VLT HVAC Drive
The following is an example of a Closed Loop Control for a ventilation system:
2
In a ventilation system, the temperature is to
be maintained at a constant value. The de-
sired temperature is set between -5 and +35°
C using a 0-10 volt potentiometer. Because
this is a cooling application, if the temperature
1. Start/Stop via switch connected between
2. Temperature reference via a potentiome-
3. Temperature feedback via transmitter
34
terminals 12 (+24 V) and 18.
ter (-5 to +35°C, 0 10 V) connected to
terminals 50 (+10 V), 53 (input) and 55
(common).
(-10-40°C, 4-20 mA) connected to terminal
54. Switch S202 behind the Local Control
Panel set to ON (current input).
MG.11.B2.02 - VLT
is above the setpoint value, the speed of the
fan must be increased to provide more cooling
air flow. The temperature sensor has a range
of -10 to +40°C and uses a two-wire trans-
mitter to provide a 4-20 mA signal. The output
frequency range of the drive is 10 to 50 Hz.
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VLT HVAC Drive Design Guide