Analog and digital monitor output, Pwm signal type, Analog and digital monitor output 4–33 – Hitachi SJ100 User Manual
Page 150: Terminal (see
SJ100 Inverter
Oper
ations
and Monitor
ing
4–33
Analog and Digital Monitor Output
In the system design for inverter applications it is useful to monitor the inverter operation
from a remote location. In some cases, this requires only a panel-mounted analog meter
(moving-coil type). In other cases, a controller device such as a PLC may command the
inverter frequency and other functions. Sometimes it is useful to have the inverter
transmit the (real-time) output frequency value back to the controller to confirm actual
operation. The monitor output function [FM] serves these purposes.
The inverter provides an analog/digital output
primarily for frequency monitoring on terminal
[FM] (frequency monitor). It uses terminal [L] as
analog GND reference. You can configure
terminal [FM] to transmit the inverter current
output or frequency output in pulse-width
modulated format (PWM). You can also config-
ure terminal [FM] to output the frequency value in a frequency-modulated (FM) format.
The following table lists terminal [FM] configurations. Use function C_23 to configure.
PWM Signal Type
The pulse-width modulated signal at terminal
[FM] is primarily designed for driving a moving-
coil meter. The PWM signal is automatically
averaged by the inertia of the moving-coil mecha-
nism—converting the PWM signal to an analog
representation. Be sure to use a 10V full-scale DC
voltmeter.
The signal characteristics of terminal [FM] in PWM configuration is shown below:
To calibrate the meter reading, generate a full-scale output (always ON) at terminal
[FM]. Then use parameter B_81(gain setting from 0 to 255) to adjust the corresponding
full-scale reading of the meter. For example, when the inverter output frequency is
60 Hz, change the value of B_81 so that the meter reads 60 Hz.
Func.
Code
Description
Waveform
Full Scale value
C_23
00
Output frequency
PWM
0 – Max. frequency (Hz)
01
Output current
PWM
0 – 200%
02
Output frequency
FM
0 – Max. frequency (Hz)
A GND
Analog/digital Output
12 11
L
H O OI
FM CM2
See I/O specs on page
.
0 to 10V,
1 mA
12 11
L
H O OI
FM CM2
–
+
Inverter output current
[FM]
Inverter output frequency
Pulse-width modulation (analog)
PWM scale factor
C_23 = 00
C_23 = 01
B 81
10V
0V
T
T = 4 ms
t
[FM] Output
t
T
---
=
t