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VLT
®
HVAC Drive Instruction Manual
20-00 Feedback 1 Source
Option:
[0]
No function
[1]
Analog input 53
[2] *
Analog input 54
[3]
Pulse input 29
[4]
Pulse input 33
[7]
Analog input X30/11
[8]
Analog input X30/12
[9]
Analog Input X42/1
[10]
Analog Input X42/3
[11]
Analog Input X42/5
[100]
Bus feedback 1
[101]
Bus feedback 2
[102]
Bus feedback 3
[104]
Sensorless Flow
[105]
Sensorless Pressure
NOTE!
If a feedback is not used, its source must be set to
feedbacks will be used by the PID controller.
20-01 Feedback 1 Conversion
Option:
[0] *
Linear
[1]
Square root
[2]
Pressure to temperature
[3]
[4]
Function:
Up to three different feedback signals can be used to provide the feedback signal for the adjustable
frequency drive'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 purpose I/O
board.
Requires set up by MCT10 with sensorless specific plug in.
Requires set up by MCT10 with sensorless specific plug in.
No Function
[0]. Par. 20-20
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 feedback
( (
flow
∝
pressure
) ).
Pressure to temperature
[2] is used in compressor applications to provide temperature feedback
using a pressure sensor. The temperature of the refrigerant is calculated using the following for-
mula:
A
2
Temperature
=
(
ln
(
Pe
+ 1 ) −
stants. The refrigerant must be selected in par. 20-30
Setpoint 3
par. 20-23
allow the values of A1, A2 and A3 to be entered for a refrigerant that is not
Refrigerant
listed in par. 20-30
.
MG.11.AB.22 - VLT
®
is a registered Danfoss trademark
7 How to Program the Adjustable Frequency
Feedback Function
determines how the three possible
A
−
3 , where A1, A2 and A3 are refrigerant-specific con-
A
1 )
Refrigerant
. Par. 20-21
Drive
7
Setpoint 1
through
7-33
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