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2) In systems where the pressure or temperature is controlled by an external PI controller, the wake up conditions can not be based on feedback from
the pressure/temperature transducer as the setpoint is not known. In the example with a boost system, desired pressure P
set
is not known. Par. 1-00,
Configuration mode
, must be set for Open Loop.
Example: Boost system.
When low power or low speed is detected the motor is stopped, but the reference signal (f
ref
) from the external controller is still monitored and because
of the low pressure created, the controller will increase the reference signal to gain pressure. When the reference signal has reached a set value f
wake
the motor restarts.
The speed is set manually by an external reference signal (Remote Reference). The settings (par. 22-3*) for tuning of the No Flow function must be set
to default.
Configuration possibilities, overview:
Internal PI Controller
(Par. 1-00: Closed loop)
External PI Controller or manual control
(Par. 1-00: Open loop)
Sleep mode
Wake up
Sleep mode
Wake up
No Flow detection (pumps only)
Yes
Yes (except manual setting
of speed)
Low speed detection
Yes
Yes
External signal
Yes
Yes
Pressure/Temperature (transmit-
ter connected)
Yes
No
Output frequency
No
Yes
2 Parameter Description
VLT
®
AQUA Drive Programming Guide
190
MG.20.O4.02 - VLT
®
is a registered Danfoss trademark
2