Danfoss VLT AQUA Drive FC 202 Programming Manual page 98

Parameter Description
6-50 Terminal 42 Output
Option:
[157] Flow Rate
4-20mA
[254] DC Link
3 3
0-20mA
[255] DC Link
4-20mA
96
®
VLT
Function:
With this parameter selected, the terminal
output shows the scaled DC-link voltage.
Table 3.17 shows the relationship between
the DC-link voltage and the terminal output.
DC-link voltage (V) Terminal
output
V ≤undervoltage limit
0%
V ≥overvoltage limit
100%
Voltage within range: Linearly
Undervoltage <V interpolated
<overvoltage
Table 3.17 Relationship between the DC-
link Voltage and the Terminal Output
Table 3.18 shows the undervoltage and
overvoltage limits for different frequency
converter sizes.
Frequency Undervoltage Overvoltage
converter limit [V] limit [V]
size
T2/S2 185 410
T4/S4 373 855
T6/T7 553 1130
Table 3.18 Undervoltage and Overvoltage
Limits for Different Frequency Converter
Sizes
I
1
20
3
2
10
0
800 1200
0 400
1 Analog output
2 Undervoltage limit
3 Overvoltage limit
Illustration 3.35 Example: The Analog
Output of Terminal 42 on the T4
Frequency Converter with Option [254] DC
Link 0–20 mA Selected
The function is the same as [254] DC Link 0–
20 mA.
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AQUA Drive FC 202
6-51 Terminal 42 Output Min Scale
Range:
0 % [0 -
*
200 %]
6-52 Terminal 42 Output Max Scale
Range:
100 [0 -
% 200
*
%]
Example 1:
Variable value = output frequency, range = 0–100 Hz.
Range needed for output = 0–50 Hz.
Output signal 0 mA or 4 mA is needed at 0 Hz (0% of
range). Set parameter 6-51 Terminal 42 Output Min Scale to
0%.
Output signal 20 mA is needed at 50 Hz (50% of range).
Set parameter 6-52 Terminal 42 Output Max Scale to 50%.
V
DC
20 mA
0/4 mA
0%
0Hz
Illustration 3.37 Example 1
Function:
Scale for the minimum output (0 mA or 4 mA)
of the analog signal at terminal 42.
Set the value to be the percentage of the full
range of the variable selected in
parameter 6-50 Terminal 42 Output.
Function:
Scale for the maximum output (20 mA) of the
analog signal at terminal 42.
Set the value to be the percentage of the full
range of the variable selected in
parameter 6-50 Terminal 42 Output.
Current
(mA)
20
0/4
0% Analog Analog
output output
min scale max scale
par. 6-51 par. 6-52
Illustration 3.36 Output Current vs Reference
Variable
It is possible to obtain a value lower than 20 mA
at full scale by programming values >100% by
using a formula as follows:
20 mA/desired maximum current × 100 %
20 mA
i . e . 10mA: × 100 % = 200 %
10 mA
50%
50Hz
100% Variable for
output
example:
Speed (RPM)
100%
100Hz
MG20OB02