Danfoss VLT FC 100, Operating Instructions Manual, Page: 123 / 193

[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
[15] Analog Input X48/2
[100] Bus feedback 1
[101] Bus feedback 2
[102] Bus feedback 3
[104] Sensorless Flow Requires set up by MCT 10 Set-up Software with sensorless specific plug in.
[105] Sensorless Pressure Requires set up by MCT 10 Set-up Software with sensorless specific plug in.
If a feedback is not used, its source must be set to
No Function
[0]. Par. 20-20
Feedback Function
deter-
mines how the three possible feedbacks will be used
by the PID Controller.
20-01 Feedback 1 Conversion
Option: Function:
This meter allows a conversion function to be applied to Feedback 1.
[0] * Linear Linear [0] has no effect on the feedback.
[1] Square root
Square root
[1] is commonly used when a pressure sensor is used to provide flow feedback
( (
flow
∝
pressure
) ).
[2] Pressure to temperature 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:
Temperature
=
A 2
( ln ( Pe
+ 1) −
A
1) −
A
3 ,
where A1, A2 and A3 are refrigerant-specific constants. The refrigerant must be selected in
par. 20-30
Refrigerant . Par. 20-21 Setpoint 1 through par. 20-23 Setpoint 3 allow the values of
A1, A2 and A3 to be entered for a refrigerant that is not listed in par. 20-30 Refrigerant .
[3] Pressure to flow Pressure to flow is used in applications where the air flow in a duct is to be controlled. The feed-
back signal is represented by a dynamic pressure measurement (pitot tube).
Flow
=
Duct Area
×
Dynamic Pressure
×
Air Density Factor
See also par. 20-34 Duct 1 Area [m2] through par. 20-38 Air Density Factor [%] for setting of
duct area and air density.
[4] Velocity to flow Velocity to flow is used in applications where the air flow in a duct is to be controlled. The feed-
back signal is represented by an air velocity measurement.
Flow
=
Duct Area
×
Air Velocity
See also par. 20-34
Duct 1 Area [m2]
through par. 20-37
Duct 2 Area [in2]
for setting of duct
area.
6 How to Programme
VLT HVAC Drive High Power Operating In-
structions
122
MG.11.F3.02 - VLT ® is a registered Danfoss trademark
6