47
Fn26-28
are used to customize the remote frequency command (speed reference) to obtain the
desired inverter frequency output.
The bias (
Fn26
), polarity (
Fn27
) and maximum frequency output (
Fn28
) of the remote analog
frequency command at terminal #13 are as follows:
Example of operation shown by line A.
Set
Fn26
= minimum frequency output when the speed reference is zero.
Set
Fn27=0
Set
Fn28
= maximum frequency when the speed reference is at maximum.
Example of operation shown by line B.
Set
Fn26=0
Set
Fn27=0
Set
Fn28
= maximum frequency when the speed reference is at maximum.
Example of operation shown by line C.
Set
Fn26=Fn28
x
P
Ref. max. - P
Where
Fn28
is the maximum frequency when the speed reference is at maximum.
P is the value of speed reference where output frequency is zero.
Reference maximum is the maximum speed reference. (refer to setting of
Fn28
above)
EXAMPLE:
Speed range required 0-50Hz with a 4-20mA signal. What are the values for
Fn26
,
Fn27
and
Fn28
.
Fn28
=50Hz (maximum frequency with maximum speed reference)
Fn27=1
Fn26=Fn28
x
P
Ref. max. - P
P=4: Speed reference where output frequency is zero.
Reference maximum = 20: Maximum speed reference.
Curve
)Q
)Q
)Q
A
Any value
0
0-180 Hz
B
0
0
C
Obtain from
formula
1
Table 5.3g
Fig. 5.3o
