Hitachi SJ Series, User Manual

Page: 467 / 786

13-4
Chapter 13 Monitor Functions
13.2.3 Monitoring converted frequency
• Want to change the displayed frequency command
value.
• On the frequency conversion monitor, the frequency
value obtained by multiplying the coefficient which is
set in the frequency conversion coefficient [Ab-01]
can be shown. Use this method when you want to
change the displayed value of data such as motor
rotation speed, etc.
• Example of conversion of displayed frequency
“Value displayed on frequency conversion monitor
[dA-
06]” = “Frequency command (Hz)” x
“ Frequency conversion coefficient [Ab-01]”
(Example) Displaying the motor rotation speed
The relationship of rotation speed and frequency is
as shown below:
Rotation speed N (min
-1
) = (120 x f (Hz))/P (poles)
When the motor frequency is 60Hz and the number
of poles is 4, the coefficient is 30; hence at 60Hz,
where [Ab-01]=30.00,
“60×30.0=1800 (min
-1
)” will
be displayed on the monitor.

Parameter
• In this monitor, gain is applied to the output
frequency monitor [dA-01].
Table of sample conversions
Motor
frequency
(Hz)
Number
of motor
poles (P)
Coefficient
[Ab-01]
Synchronous
rotation
[min-1]
50 2 60 3000
50 4 30 1500
50 6 15 750
50 8 7.5 375
60 2 60 3600
60 4 30 1800
60 6 15 900
60 8 7.5 450
Item Parameter Data Description
Frequency conversion
monitor
[dA-06] 0.00~59000.00 (Hz) Converted output frequency is displayed.
Frequency conversion
coefficient
[Ab-01] 0.01~100.00
Set the gain of frequency conversion
monitor.
Q
A
!