Danfoss VLT Series Programming Manual page 154

Parameter Description
22-44 Wake-up Ref./FB Difference
Range: Function:
10 % [0 - 100 Only to be used if 1-00 Configuration Mode is
*
%] set for Closed Loop and the integrated PI
controller is used for controlling the pressure.
Set the pressure drop allowed in percentage
of set point for the pressure (Pset) before
cancelling the Sleep Mode.
NOTE
If used in application where the integrated PI controller is
set for inverse control (e.g. cooling tower applications) in
20-71 PID Performance, the value set in 22-44 Wake-up
Ref./FB Difference will automatically be added.
22-45 Setpoint Boost
Range: Function:
0 [-100 Only to be used if 1-00 Configuration Mode, is set
% - 100 for Closed Loop and the integrated PI controller is
*
%] used. In systems with e.g. constant pressure
control, it is advantageous to increase the system
pressure before the motor is stopped. This will
extend the time in which the motor is stopped
and help to avoid frequent start/stop.
Set the desired over pressure/temperature in
percentage of set point for the pressure (Pset)/
temperature before entering the Sleep Mode.
If setting for 5%, the boost pressure will be
Pset*1.05. The negative values can be used for
e.g. cooling tower control where a negative
change is needed.
22-46 Maximum Boost Time
Range: Function:
60 s [0 - Only to be used if 1-00 Configuration Mode is set
*
600 s] for Closed Loop and the integrated PI controller
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, not waiting for the
set boost pressure to be reached.
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 4-13 Motor Speed High Limit [RPM] or 4-14 Motor
Speed High Limit [Hz].
In case the feed back is 2.5% of the programmed value in
20-14 Maximum Reference/Feedb. (or numerical value of
20-13 Minimum Reference/Feedb. whichever is highest)
below the set point for the desired pressure for a set time
®
VLT HVAC Drive Programming Guide
(22-51 End of Curve Delay), and the pump is running with
max. speed set in 4-13 Motor Speed High Limit [RPM] or
4-14 Motor Speed High Limit [Hz], - the function selected in
22-50 End of Curve Function will take place.
It is possible to get a signal on one of the digital outputs
by selecting End of Curve [192] in parameter group 5-3*
Digital Outputs and/or parameter group 5-4* Relays. The
signal will be present, when an End of Curve condition
occurs and the selection in 22-50 End of Curve Function, is
different from Off. The end of curve function can only be
used when operating with the built-in PID controller
(Closed loop in 1-00 Configuration Mode).
22-50 End of Curve Function
Option:
[0]
[1]
[2]
[3]
NOTE
Automatic restart will reset the alarm and start the system
again.
NOTE
Do not set 14-20 Reset Mode, to [13] Infinite auto reset,
when 22-50 End of Curve Function is set to [2] Alarm. Doing
so will cause the drive to continuously cycle between
running and stopping when a End of Curve condition is
detected.
NOTE
If the drive is equipped with a constant speed bypass with
an automatic bypass function that starts the bypass if the
drive experiences a persistent alarm condition, be sure to
disable the bypass's automatic bypass function, if [2] Alarm
or [3] Man. Reset Alarm is selected as the End of Curve
Function.
®
MG.11.CC.02 - VLT is a registered Danfoss trademark
Function:
Off End of Curve monitoring not active.
*
Warning The drive will continue to run, but activate a
End of Curve warning [W94]. A drive digital
output or a serial communication bus can
communicate a warning to other equipment.
Alarm The drive will stop running and activate a End
of Curve alarm [A 94]. A drive digital output
or a serial communication bus can
communicate an alarm to other equipment.
Man. Reset The drive will stop running and activate a End
Alarm of Curve alarm [A 94]. A drive digital output
or a serial communication bus can
communicate an alarm to other equipment.
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