Danfoss VLT HVAC Operating Instructions Manual page 78

6. How to programme the frequency converter
20-00
Value:
No Function
Analog Input 53
6
Analog Input 54
Frequency Input 29
Frequency Input 33
Analog Input X30/11
Analog Input X30/12
Analog Input X42/1
Analog Input X42/3
Bus Feedback 1
Bus Feedback 2
Bus Feedback 3
Function:
Up to three different feedback signals can be
used to provide the feedback signal for the
frequency converter's PID Controller.
This parameter defines which input will be
used as the source of the first feedback signal.
Analog input X30/11 and Analog input X30/12
refer to inputs on the optional General Pur-
pose I/O board.
20-01
Value:
Linear
Square root
Pressure to temperature
78
par. 14-00 and the section
rating
.
NB!
Switching frequencies higher
than 5.0 kHz lead to automatic
derating of the maximum output
of the frequency converter.
Feedback 1 Source
[100]
[101]
[102]
NB!
If a feedback is not used, its
No Func-
source must be set to
tion [0]. Parameter 20-10 deter-
mines how the three possible
feedbacks will be used by the
PID Controller.
Feedback 1 Conversion
MG.11.A4.02 - 09.10.06. VLT
®
VLT
De-
Function:
This parameter allows a conversion function
to be applied to Feedback 1.
Linear
[0] has no effect on the feedback.
Square root [1] is commonly used when a
pressure sensor is used to provide flow feed-
back ( (
flow
∝
Pressure to temperature
pressor applications to provide temperature
feedback using a pressure sensor. The tem-
perature of the refrigerant is calculated using
the following formula:
Temperature
=
are refrigerant-specific constants. The refrig-
[0]
erant must be selected in parameter 20-20.
[1]
Parameters 20-21 through 20-23 allow the
[2]
values of A1, A2 and A3 to be entered for a
[3]
refrigerant that is not listed in parameter
[4]
20-20.
[7]
[8]
[9]
[10]
20-03 Feedback 2 Source
Function:
Feedback 1 Source
See
20-04 Feedback 2 Conversion
Function:
Feedback 1 Conversion
See
tails.
20-06 Feedback 3 Source
Function:
Feedback 1 Source
See
20-07 Feedback 3 Conversion
Function:
Feedback 1 Conversion
See
details.
[0]
[1]
[2]
® is a registered Danfoss trademark
HVAC Drive Operating Instructions
) ).
pressure
24] is used in com-
A
, where A1, A2 and A3
2
, par. 20-00 for details.
par. 20-01 for de-
, par. 20-00 for details.
, par. 20-01 for