Return Fan - ABB DriveIT ACH550-01 User Manual

3. Return fan

This application macro is for return fan applications where the
return fan takes air out of the room according to the signals
received from the transducer. See the following figure.
When using a direct speed reference in AUTO mode, the speed
reference must be connected to analog input 1 (AI1) and the
START command is given with digital input 1 (DI1). In HAND/
OFF mode, the speed reference and START command are
given through the control panel.
If process PI(D) is used, the feedback signal must be connected
to analog input 2 (AI2). Setpoint is set from the control panel as
default but it also can be changed to analog input 1. Process
PI(D) must be commissioned and adjusted with parameters
(Group 40) or using the PID control assistant (recommended).
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ACH550 User's Manual
Wiring and applications