Danfoss VLT HVAC Series Programming Manual page 207

VLT ® HVAC Drive Programming Guide
21-00 Closed-loop Type
Option:
[0] * Auto
[1] Fast Pressure
[2] Slow Pressure
[3] Fast Temperature
[4] Slow Temperature
21-01 Tuning Mode
Option:
[0] * Normal
[1] Fast
21-02 PID Output Change
Range:
0.10 N/A* [0.01 - 0.50 N/A]
21-03 Minimum Feedback Level
Range:
-999999.00 [-999999.999 - par. 21-04 N/A]
0 N/A*
21-04 Maximum Feedback Level
Range:
999999.000 [par. 21-03 - 999999.999 N/A]
N/A*
Function:
This parameter defines the application response. The default mode should be sufficient for most
applications. If the relative application speed is known, it can be selected here. This will decrease
the time needed for carrying out PID autotuning. The setting has no impact on the value of the
tuned parameters and is used only for the PID autotuning sequence.
Function:
Normal setting of this parameter will be suitable for pressure control in fan systems.
Fast setting would generally be used in pumping systems, where a faster control response is de-
sirable.
Function:
This parameter sets the magnitude of step change during autotuning. The value is a percentage of
full operating range. This means that if maximum analog output voltage is set to 10 V, 0.10 is 10%
of 10 V, which is 1 V. This parameter should be set to a value resulting in feedback changes of
between 10% and 20% for best tuning accuracy.
Function:
The minimum allowable feedback level should be entered here in user units as defined in par.
Ext. 1 Ref./Feedback Unit
21-10
par.21-50 Ext. 3 Ref./Feedback Unit
back Level , PID autotuning is aborted and an error message will appear on the LCP.
Function:
The maximum allowable feedback level should be entered here in user units as defined in par.
21-10 Ext. 1 Ref./Feedback Unit
par.21-50 Ext. 3 Ref./Feedback Unit
Feedback Level
, PID autotuning is aborted and an error message will appear on the LCP.
MG.11.C6.22 - VLT ® is a registered Danfoss trademark
Ext. 2 Ref./Feedback Unit
for EXT CL 1, par.21-30
for EXT CL 3. If the level falls below par.21-03
for EXT CL 1, par.21-30 Ext. 2 Ref./Feedback Unit
for EXT CL 3. If the level rises above par.21-04
3 Parameter Description
3
for EXT CL 2 or
Minimum Feed-
for EXT CL 2 or
Maximum
3-183