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Illustration 2.6: Legend: FC=frequency converter; f
O
=frequency out; P
S
=P system; P
SL
=P setpoint
1) Systems where the integrated PI controller is used for controlling pressure or temperature e.g. boost systems with a pressure feed back signal applied
to the frequency converter from a pressure transducer. Par. 1-00,
Configuration Mode
, must be set for Closed Loop and the PI Controller configured for
desired reference and feed back signals.
Example: Boost system.
If no flow is detected, the frequency converter will increase the set point for pressure to ensure a slight over pressure in the system (boost to be set in
par. 22-45,
Setpoint Boost
).
The feedback from the pressure transducer is monitored and when this pressure has dropped with a set percentage below the normal set point for
pressure (Pset), the motor will ramp up again and pressure will be controlled for reaching the set value (Pset).
VLT
®
AQUA Drive Programming Guide
2 Parameter Description
MG.20.O4.02 - VLT
®
is a registered Danfoss trademark
189
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