20-22 Setpoint 2
Range:
Function:
0
ProcessCtrlUnit
*
[-999999.999 -
999999.999
ProcessCtrlUnit]
Setpoint 2 is used in closed-
loop mode to enter a setpoint
reference that may be used
by the frequency converter’s
PID controller. See the
description of
parameter 20-20 Feedback
Function
NOTICE
The setpoint reference
entered here is added to
any other references that
are enabled (see
parameter group 3-1*
References).
20-23 Setpoint 3
Range:
Function:
0
ProcessCtrlUnit
*
[-999999.999 -
999999.999
ProcessCtrlUnit]
Setpoint 3 is used in Closed
Loop Mode to enter a
setpoint reference that may
be used by the frequency
converter’s PID Controller. See
the description of
parameter 20-20 Feedback
Function
.
NOTICE
The setpoint reference
entered here is added to
any other references that
are enabled (see
parameter group 3-1*).
3.18.3 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 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:
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 options [0] through [6],
select
[7] User defined
. Then, use
20-30 Refrigerant
Option:
Function:
parameter 20-31 User Defined Refrigerant A1
parameter 20-32 User Defined Refrigerant A2
and
parameter 20-33 User Defined Refrigerant A3
to
provide A1, A2 and A3 for the equation below:
Temperature =
A2
ln Pe + 1 − A1 − A3
[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
*
[8 - 12 ] Use this parameter to enter the value of
coefficient A1 when
is
set to
[7] User defined
.
20-32 User Defined Refrigerant A2
Range:
Function:
-2250
*
[-3000 -
-1500 ]
Use this parameter to enter the value of
coefficient A2 when
is set to
[7] User
defined
.
20-33 User Defined Refrigerant A3
Range:
Function:
250
*
[200 -
300 ]
Use this parameter to enter the value of
coefficient A3 when
is set to
[7] User
defined
.
20-34 Duct 1 Area [m2]
Range:
Function:
0.500
m2
*
[0.001
- 10 m2]
Used for setting the area of the air ducts in
connection with feedback conversion
pressure/velocity to flow. The unit (m
2
) is
determined by the setting of
parameter 0-03 Regional Settings
. Fan 1 is used
with feedback 1. In case of flow difference
control, set
parameter 20-20 Feedback Function
to
[1] Difference
, if flow fan 1 – flow fan 2 is to
be controlled.
20-35 Duct 1 Area [in2]
Range:
Function:
750
in2
*
[1 -
15500
in2]
Used for setting the area of the air ducts in
connection with feedback conversion pressure/
velocity to flow. The unit (in
2
) is determined by
Parameter Descriptions
VLT
®
HVAC Drive FC 102
146
Danfoss A/S © 03/2015 All rights reserved.
MG11CE02
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