IMO Precision Controls Jaguar VXS - Page 35

This function adds a positive or negative bias to
the frequency reference input, whether the
inverter is in keypad mode (Function 01 = 0) or
terminal mode (Function 01 = 1). The input ref-
erence can be biased from -400Hz to +400Hz
(output) in steps of 1Hz.
Function 35 is active only if Function 01 = 1.
Sets the gradient of the change of output fre-
quency corresponding to the analog input fre-
quency reference as a percentage of maximum
frequency (Function 03).
The range of the gain setting is from zero to
9.99 in steps of 0.01, and from 10.0 to 250.0 in
steps of 0.1 — percent of Function 03.
NOTE If a setting is applied to both
Functions 35 and 34 then Function 35, the
gain, has priority and the bias, Function
34, is applied to the reference after the
gain.
The bias frequency f
bias
and gain f
gain
are cal-
culated from the following expressions, where
V
1
, V
2
, f
1
, f
2
are as shown in the diagram:
f
bias
= f
1
-
V
1
(f
1
- f
2
)
V
1
- V
2
f
gain
=
1000 (f
1
- f
2
)
100(V
1
-V
2
) + (f
1
V
2
)-(f
2
V
1
)
Example:
If the analog frequency reference is 1V to 5V
DC and the output frequency is weighted to 0
to 100% then:
(V
1
, f
1
) = (1V, 0%)
(V
2
, f
2
) = (5V, 100%).
Applying these values to the above formulae
gives:
f
bias
= -25% and
f
gain
= 200%
33
34 Bias frequency
Output
after bias
Unbiased
output
Output
Hz
Reference
Function 34
WARNING If a bias has been set, the motor
may rotate when any operating com-
mand is given, keypad or terminal—
even if the input reference is zero.
35 Frequency reference gain
Output
Hz
Function 35 = 70%
70%
100%
Modified
output
Output
Hz
Function 35 = 200%
100%
200%
Reference
+ gain
Normal
output
Reference
Reference
Modified
output
Normal
output
Output
Hz %
Reference
100%
0
Bias
1V 5V 10V
(V
1
, f
1
)
(V
2
, f
2
)