Danfoss VLT FC 100 Series Programming Manual page 160

Parameter Description
NOTE!
In pump systems, ensure that the minimum speed in
4-11 Motor Speed Low Limit [RPM] or 4-12 Motor Speed Low
Limit [Hz] has been set high enough for detection as the
pump can run with a rather high speed even with valves
closed.
Dry pump detection:
No-Flow Detection can also be used for detecting if the
pump has run dry (low power consumption-high speed).
Can be used with both the integrated PI controller and an
external PI controller.
The condition for Dry Pump signal:
- Power consumption below no-flow level
and
- Pump running at maximum speed or maximum
reference open-loop, whichever is lowest.
The signal must be active for a set time (22-27 Dry Pump
Delay) before selected action takes place.
Possible Actions to select (22-26 Dry Pump Function):
- Warning
- Alarm
No-Flow Detection must be enabled (22-23 No-Flow
Function) and commissioned (parameter group 22-3*, No
Power Tuning).
22-20 Low Power Auto Set-up
Start of auto set-up of power data for No-Flow Power tuning.
Option: Function:
[0] OFF
*
[1] Enabled When set for Enabled, an auto set-up sequence is
activated, automatically setting speed to approx.
50% and 85% of rated motor speed (4-13 Motor
Speed High Limit [RPM], 4-14 Motor Speed High
Limit [Hz]). At those two speeds, the power
consumption is automatically measured and
stored.
Before enabling Auto Set-up:
1. Close valve(s) in order to create a no-
flow condition
2. The Adjustable frequency drive must be
set for Open-Loop (1-00 Configuration
Mode).
Note that it is important also to set
1-03 Torque Characteristics.
NOTE!
Auto set-up must be done when the system has reached
normal operating temperature!
®
VLT HVAC Drive Programming Guide
NOTE!
It is important that the 4-13 Motor Speed High Limit [RPM]
or 4-14 Motor Speed High Limit [Hz] is set to the max.
operational speed of the motor!
It is important to do the auto set-up before configuring
the integrated PI controller as settings will be reset when
changing from Closed to Open-Loop in 1-00 Configuration
Mode.
NOTE!
Carry out the tuning with the same settings in 1-03 Torque
Characteristics, as for operation after the tuning.
22-21 Low Power Detection
Option:
[0]
[1]
22-22 Low Speed Detection
Option:
[0]
[1]
22-23 No-Flow Function
Common actions for Low Power Detection and Low Speed
Detection (Individual selections not possible).
Option:
[0]
[1]
[2]
[3]
MG11CD22 - VLT ® is a registered Danfoss trademark
Function:
Disabled
*
Enabled If selecting Enabled, the Low Power Detection
commissioning must be carried out in order to
set the parameters in parameter group 22-3* for
proper operation!
Function:
Disabled
*
Enabled Select Enabled for detecting when the motor
operates with a speed as set in 4-11 Motor Speed
Low Limit [RPM] or 4-12 Motor Speed Low Limit
[Hz].
Function:
OFF
*
Sleep Mode The adjustable frequency drive will enter
Sleep Mode and stop when a No-Flow
condition is detected. See parameter group
22-4* for programming options for Sleep
Mode.
Warning The drive will continue to run, but activate a
No-Flow Warning [W92]. A drive digital output
or a serial communication bus can
communicate a warning to other equipment.
Alarm The adjustable frequency drive will stop
running and activate a No-Flow Alarm [A 92].
An adjustable frequency drive digital output
or a serial communication bus can
communicate an alarm to other equipment.
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