Danfoss VLT FC 100 Series Programming Manual page 160

3. Parameter Description
3.18.4. 20-3* Feedback Adv. Conversion
In air conditioning compressor applications it is often useful to control the system based on the temperature of the refrigerant. However, it is generally
3
more convenient to directly measure its pressure. This parameter group allows the frequency converter's PID Controller to convert refrigerant pressure
measurements into temperature values.
20-30 Refrigerant
Option:
* R22
[0]
[1] R134a
[2] R404a
[3] R407c
[4] R410a
[5] R502
[6] R744
[7] User defined
20-31 User Defined Refrigerant A1
Range:
*
10 [8 - 12]
20-32 User Defined Refrigerant A2
Range:
*
-2250 [-3000 - -1500]
20-33 User Defined Refrigerant A3
Range:
*
250 [200 - 300]
3.18.5. 20-7* PID autotuning
The frequency converter PID Closed Loop controller (parameters 20-**, FC Closed Loop) can be auto-tuned, simplifying and saving time during com-
missioning, whilst ensuring accurate PID control adjustment. To use autotuning it is necessary for the frequency converter to be configured for Closed
loop in par 1-00 Configuration Mode.
A Graphical Local Control Panel (LCP) must be used in order to react on messages during the autotuning sequence.
Enabling autotuning par 20-79
160
NB!
The setpoint reference entered here is added to any other references that are enabled (see
par. group 3-1*).
Function:
Select the refrigerant used in the compressor application. This parameter must be specified correctly for the
pressure to temperature conversion to be accurate. If the refrigerant used is not listed in choices [0] through
[6], select User defined [7]. Then, use par. 20-31, 20-32 and 20-33 to provide A1, A2 and A3 for the equation
below:
Temperature
=
( ln (
Function:
Use this parameter to enter the value of coefficient A1 when par. 20-30 is set to
Function:
Use this parameter to enter the value of coefficient A2 when par. 20-30 is set to
Function:
Use this parameter to enter the value of coefficient A3 when par. 20-30 is set to
, puts the frequency converter into autotuning mode. The LCP then directs the user with on-screen instructions.
MG.11.C5.02 - VLT
VLT
A
2
A
− 3
Pe + 1 ) − A 1 )
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HVAC Drive Programming Guide
User defined [7].
User defined [7].
User defined [7].