No Flow Detection
This function is used for detecting a no-ow situation in pump systems where all valves can be closed. Can be used both
when controlled by the integrated PI controller in the frequency converter or an external PI controller. Programme the
actual conguration in parameter 1-00 Conguration Mode.
Conguration mode for
•
Integrated PI controller: Closed loop
•
External PI controller: Open loop
NOTICE
Carry out no-ow tuning before setting the PI controller parameters.
Table 3.23 No Flow Detection
No-ow
Detection
No-ow detection is based on the measurement of speed and power. For a certain speed, the frequency converter calculates
the power at no ow.
This coherence is based on the adjustment of 2 sets of speed and associated power at no-ow. By monitoring the power, it
is possible to detect no-ow conditions in systems with uctuating suction pressure, or if the pump has a at characteristic
towards low speed.
The 2 sets of data must be based on measurement of power at approximately 50% and 85% of maximum speed with the
valve(s) closed. The data is programmed in parameter group 22-3* No-Flow Power Tuning. It is also possible to run a [0] Low
Power Auto Set Up (parameter 22-20 Low Power Auto Set-up) automatically stepping through the commissioning process and
also automatically storing the data measured. The frequency converter must be set for [0] Open Loop in
parameter 1-00 Conguration Mode, when carrying out the Auto Set Up (See parameter group 22-3* No-Flow Power Tuning No-
ow Power Tuning).
NOTICE
If to use the integrated PI controller, carry out no-ow tuning before setting the PI controller parameters.
Parameter Descriptions
VLT
®
HVAC Drive FC 102
160 Danfoss A/S © 03/2015 All rights reserved. MG11CE02
33
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