Danfoss VLT HVAC Basic Drive FC 101 Programming Manual page 91

Parameters
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 1-00 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.
FC
P
Table 3.11 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 22-3* No-Flow Power Tuning.
Enable and commission no-flow detection in parameter 22-23 No-Flow Function and parameter group 22-3* No-Flow Power
Tuning.
22-23 No-Flow Function
Option:
[0] Off
*
[1] Sleep Mode
[2] Warning
[3] Alarm
22-24 No-Flow Delay
Range:
10 s [1 - 600 s]
*
MG18B502
Programming Guide
Head
1
2
Function:
Function:
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Flow
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