20-30 Refrigerant
Option:
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], use par.20-31
to provide A1, A2 and
A3 for the equation below:
Temperature
=
A
2
(
ln
(
Pe
+ 1)
−
A
1)
−
A
3
[0] *
R22
[1]
R134a
[2]
R404a
[3]
R407c
[4]
R410a
[5]
R502
[6]
R744
[7]
User-defined
20-31 User-defined Refrigerant A1
Range:
Function:
10.0000 N/
A*
[8.0000 - 12.0000 N/A]
Use this parameter to enter the value of coefficient A1 when par.20-30
is set to
User-
defined
[7].
20-32 User-defined Refrigerant A2
Range:
Function:
-2250.00 N/
A*
[-3000.00 - -1500.00 N/A]
Use this parameter to enter the value of coefficient A2 when par.20-30
is set to
User-
defined
[7].
20-33 User-defined Refrigerant A3
Range:
Function:
250.000 N/
A*
[200.000 - 300.000 N/A]
Use this parameter to enter the value of coefficient A3 when par.20-30
is set to
User-
defined
[7].
3.18.5 20-7* PID autotuning
The adjustable frequency drive PID closed-loop controller (parameters 20-**, Adjustable Frequency Drive Closed-loop) can be autotuned, simplifying and
saving time during commissioning, while ensuring accurate PID control adjustment. To use autotuning, it is necessary for the adjustable frequency drive
to be configured for closed-loop in par.1-00
A graphical local control panel (LCP) must be used in order to react on messages during the autotuning sequence.
Enabling par.20-79
, puts the adjustable frequency drive into autotuning mode. The LCP then directs the user with on-screen instructions.
The fan/pump is started by pressing [Auto On] button on the LCP and applying a start signal. The speed is adjusted manually by pressing the [
▲
] or
[
▼
] navigation keys on the LCP to a level where the feedback is around the system setpoint.
VLT
®
HVAC Drive Programming Guide
3 Parameter Description
MG.11.C6.22 - VLT
®
is a registered Danfoss trademark
3-177
3