Parameter
Description of function
PID Anti Windup
par.
20-91
On
[1] effectively disables the Closed Loop Controller’s
integral function when it is not possible to adjust the
output frequency of the drive to correct the error. This
allows the controller to respond more quickly once it
can again control the system.
Off
[0] disables this func-
tion, making the integral function stay active continu-
ously.
PID Differentiation Time par.
20-95
This controls the output of the drive’s Closed Loop Con-
troller based on the rate of change of feedback. While
this can provide fast controller response, such response
is seldom needed in HVAC systems. The default value
for this parameter is Off, or 0.00 s.
PID Diff. Gain Limit
par.
20-96
Because the differentiator responds to the rate of
change of the feedback, a rapid change can cause a
large, undesired change in the output of the controller.
This is used to limit the maximum effect of the differ-
entiator. This is not active when par. 20-95 is set to Off.
Lowpass Filter Time :
Analog Input 53
Analog Input 54
Digital (pulse) input 29
Digital (pulse) input 33
par. 6-16
par. 6-26
par. 5-54
par. 5-59
This is used to filter out high frequency noise from the
feedback signal. The value entered here is the time
constant for the low pass filter. The cut-off frequency
in Hz can be calculated as follows:
F
cut
−
off
=
1
2
π
T
lowpass
Variations in the feedback signal whose frequency is
below F
cut-off
will be used by the drive’s Closed Loop
Controller, while variations at a higher frequency are
considered to be noise and will be attenuated. Large
values of Lowpass Filter Time will provide more filter-
ing, but may cause the controller to not respond to
actual variations in the feedback signal.
VLT
®
HVAC Drive Design Guide
2. Introduction to VLT HVAC Drive
MG.11.B2.02 - VLT
®
is a registered Danfoss trademark
33
2
Содержание VLT series
Страница 78: ...4 How to Order VLT HVAC Drive Design Guide 78 MG 11 B2 02 VLT is a registered Danfoss trademark 4...
Страница 120: ...7 RS 485 Installation and Set up VLT HVAC Drive Design Guide 120 MG 11 B2 02 VLT is a registered Danfoss trademark 7...
Страница 152: ...8 Troubleshooting VLT HVAC Drive Design Guide 152 MG 11 B2 02 VLT is a registered Danfoss trademark 8...