Danfoss VLT AQUA Drive FC 202 Programming Guide

If no ow is detected, the frequency converter increases
the setpoint for pressure to ensure a slight overpressure in
the system (boost to be set in parameter 22-45 Setpoint
Boost).
The feedback from the pressure transducer is monitored.
When this pressure has dropped with a set percentage
below the normal setpoint for pressure (P
set
), the motor
ramps up again. The pressure is then controlled for
reaching the set value (P
set
).
External PID
controller
FC
130BA256.11
P
P
System
P
Set
f
Out
f
Ref
Illustration 3.68 System with Pressure Feedback
In systems where the pressure or temperature is controlled
by an external PI controller, the wake-up conditions cannot
be based on feedback from the pressure/temperature
transducer as the setpoint is not known. In the example
with a boost system, pressure P
set
is not known. Set
parameter 1-00 Conguration Mode for [1] Open loop.
Example: Boost system.
130BA258.10
t
1
p
(Pressure)
Time
Time
No/Low Flow
detected
p
System
P
Set
Sleep mode
activated
P
Ref
= P
Wake
(Frequency)
f
Ref
f
Ref /
f
Out
f
Ref
f
Out
f
Wake
f
Out
Illustration 3.69 Boost System without Pressure Feedback
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 increases 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). Set the settings (parameter group 22-3*
No-Flow Power Tuning) for tuning of the no-ow function
to default.
Internal PI controller
(parameter 1-00 Conguration Mode)
External PI controller or manual control
(parameter 1-00 Conguration Mode)
Sleep mode Wake up Sleep mode Wake up
No-ow detection (pumps only) Yes – Yes (except manual
setting of speed)
–
Low-speed detection Yes – Yes –
External signal Yes – Yes –
Pressure/temperature
(transmitter connected)
– Yes – No
Output frequency – No – Yes
Table 3.29 Overview of Conguration Possibilities
NOTICE
Sleep mode is not active when local reference is active
(set speed manually with the navigation keys on the
LCP). See parameter 3-13 Reference Site.
Does not work in hand-on mode. Carry out auto set-up
in open loop before setting input/output in closed loop.
22-40 Minimum Run Time
Range: Function:
60 s* [0 - 600 s] Set the minimum running time for the motor
after a start command (digital input or
eldbus) before entering sleep mode.
Parameter Description
VLT
®
AQUA Drive FC 202
184 Danfoss A/S © 05/2018 All rights reserved. MG20OB02
33

Danfoss VLT AQUA Drive FC 202 Specifications

General

Brand	Danfoss
Model	VLT AQUA Drive FC 202
Category	DC Drives
Language	English