No-flow detection
This function is used for detecting a no-flow 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. Program the actual
configuration in
parameter H-40 Configuration Mode
Configuration mode for
•
Integrated PI controller: Closed loop.
•
External PI controller: Open loop.
NOTICE
Carry out no-flow tuning before setting the PI controller parameters.
Table 3.21 No-flow Detection
No-flow detection is based on the measurement of speed and power. For a certain speed, the frequency converter calculates
the power at no-flow.
This coherence is based on the adjustment of 2 sets of speed and associated power at no-flow. Monitoring power enables
detection of no-flow conditions in systems with fluctuating suction pressure, or of the pump having a flat 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
valves closed. The data is programmed in parameter group AP-3#. It is also possible to run a
[0] Low Power Auto Set Up
(
parameter AP-20 Low Power Auto Set-up
) automatically stepping through the commissioning process and storing the data
measured. Set the frequency converter for
[0] Open Loop
parameter H-40 Configuration Mode
, when carrying out the auto
set-up, see
parameter group AP-3# No-flow Power Tuning
.
NOTICE
If to use the integrated PI controller, carry out no-flow tuning before setting the PI controller parameters.
Parameter Description
AF-600 FP
™
Programming Guide
DET-620D
03/2016 All rights reserved.
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