Danfoss VLT HVAC Series Programming Manual page 229

VLT ® HVAC Drive Programming Guide
22-45 Setpoint Boost
Range:
0 %* [-100 - 100 %]
22-46 Maximum Boost Time
Range:
60 s* [0 - 600 s]
3.20.4 22-5* End of Curve
The End of Curve conditions occur when a pump is yielding a too large volume to ensure the set pressure. This can occur if there is a leakage in the
distribution pipe system after the pump causing the pump to operate at the end of the pump characteristic, valid for the max. speed set in par.
Motor Speed High Limit [RPM]
4-13
If the feedback is 2.5% of the programmed value in par.20-14
Feedb.
whichever is highest) below the setpoint for the desired pressure for a set time (par.22-51
max. speed set in par.4-13 Motor Speed High Limit [RPM]
Function will take place.
It is possible to get a signal on one of the digital outputs by selecting End of Curve [192] in par. 5-3*
will be present, when an End of Curve condition occurs and the selection in par.22-50
function can only be used when operating with the built-in PID controller (closed-loop in par.1-00
22-50 End of Curve Function
Option:
[0] * OFF
[1] Warning
[2] Alarm
NOTE!
Automatic restart will reset the alarm and start the system again.
22-51 End of Curve Delay
Range:
10 s* [0 - 600 s]
Function:
Only to be used if par.1-00
is used. For example, in systems with constant pressure control, it is advantageous to increase the
system pressure before the motor is stopped. This will extend the time during which the motor is
stopped and help to avoid frequent start/stop.
Set the desired over pressure/temperature as a percentage of the setpoint for the pressure (Pset)/
temperature before entering sleep mode.
If set at 5%, the boost pressure will be Pset*1.05. The negative values can be used, for example,
for cooling tower control, where a negative change is needed.
Function:
Only to be used if par.1-00
is used for controlling the pressure.
Set the maximum time for which boost mode will be allowed. If the set time is exceeded, sleep
mode will be entered and will not wait for the set boost pressure to be reached.
Motor Speed High Limit [Hz]
or par.4-14
Maximum Reference/Feedb.
or par.4-14 Motor Speed High Limit [Hz]
Function:
End of Curve monitoring not active.
A warning is issued in the display [W94].
An alarm is issued and the adjustable frequency drive trips. A message [A94] appears in the display.
Function:
When an end of curve condition is detected, a timer is activated. When the time set in this parameter
expires and the End of Curve condition has been steady in the entire period, the function set in par.
End of Curve Function
22-50
the timer will be reset.
MG.11.C6.22 - VLT ® is a registered Danfoss trademark
Configuration Mode , is set for closed-loop and the integrated PI controller
Configuration Mode
is set for closed-loop and the integrated PI controller
.
(or numerical value of par.20-13
End of Curve Delay
, - the function selected in par.22-50
Digital Outputs
End of Curve Function
, is different from Off. The end of curve
Configuration Mode
will be activated. If the condition disappears before the timer expires,
3 Parameter Description
Minimum Reference/
), and the pump is running with
End of Curve
Relays
and/or par. 5-4* . The signal
).
3-205
3