Danfoss VLT HVAC Operating Instructions Manual page 77

®
VLT HVAC Drive Operating Instructions
Ext. Closed Loop 1, 4-20 mA
Ext. Closed Loop 2, 4-20 mA
Ext. Closed Loop 3, 4-20 mA
Function:
Select the function of Terminal 42 as an ana-
log current output.
6-51
Value:
0.00 – 200%
Function:
Scale the minimum output of the selected an-
alog signal at terminal 42, as a percentage of
the maximum signal value. E.g. if 0 mA (or 0
Hz) is desired at 25% of the maximum output
value, then programme 25%. Scaling values
up to 100% can never be higher than the cor-
responding setting in par. 6-52.
6-52
Value:
0.00 – 200%
Function:
Scale the maximum output of the selected an-
alog signal at terminal 42. Set the value to the
maximum value of the current signal output.
Scale the output to give a current lower than
20 mA at full scale; or 20 mA at an output be-
low 100% of the maximum signal value. If 20
mA is the desired output current at a value
between 0 - 100% of the full-scale output,
programme the percentage value in the pa-
rameter, i.e. 50% = 20 mA. If a current be-
tween 4 and 20 mA is desired at maximum
[[143]]
[[144]]
[[145]]
Terminal 42 Output Min Scale
Terminal 42 Output
Scale
100%
MG.11.A4.02 - 09.10.06. VLT ® is a registered Danfoss trademark
6. How to programme the frequency converter
output (100%), calculate the percentage val-
ue as follows:
20 m A / desired maximum current
m A
20
i e m A
. . 10 :
10 m A
0%
14-01 Switching Frequency
Value:
1.0 kHz
1.5 kHz
2.0 kHz
2.5 kHz
3.0 kHz
3.5 kHz
4.0 kHz
5.0 kHz
6.0 kHz
7.0 kHz
8.0 kHz
10.0 kHz
12.0 kHz
14.0 kHz
Max
16.0 kHz
Function:
Select the inverter switching frequency.
Changing the switching frequency can help to
reduce acoustic noise from the motor.
NB!
The output frequency value of
the frequency converter must
never exceed 1/10 of the
switching frequency. When the
motor is running, adjust the
switching frequency in par.
14-01 until the motor is as
noiseless as possible. See also
× 100 %
× 100 % = 200 %
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