Analog Output Operation; [Fm] Terminal; Pwm Signal Type - Hitachi SJ300 Series Instruction Manual

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Analog Output Operation

Analog Output Operation

[FM] Terminal

PWM Signal Type

In the system design for inverter applications it is sometimes useful to monitor inverter opera-
tion 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 monitor and
command the inverter frequency and other functions. The inverter can transmit the (real-time)
output frequency, current, torque, or other parameters to the controller to confirm actual opera-
tion. The monitor output terminal [FM] serves these purposes.
The inverter provides an analog/digital output on
terminal [FM] (frequency monitor). It uses
terminal [CM1] as digital GND reference. While
many applications use this terminal to monitor
the output frequency, you can configure terminal
[FM] to transmit one of several parameters.
Most use pulse-width modulation (PWM) to
represent the value, while one parameter uses
frequency modulation (FM) to represent the
value. Do not confuse the notation for terminal
[FM] (with brackets) with FM signal type.
The following table lists the configurations for terminal [FM]. Use function C027 to configure.
Func. Code
00 Output frequency
01 Output current
02 Output torque *1
03 Output frequency
C027
04 Output voltage
05 Input electric power
06 Thermal load ratio
07 LAD frequency
Note 1: Display substitutes only during sensorless vector control, 0Hz domain sensorless
vector control, and vector control
The pulse-width modulated signal at terminal
[FM] is primarily designed for driving a moving-
coil meter. The pulse-width modulated signal is
automatically averaged by the inertia of the
moving-coil mechanism—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 signal configuration is shown below
[FM]
t
10V
0V
T
Period T = 6.4ms constant (156 Hz)
Analog/digital Output
D GND
See I/O specs on page 4–9.
Description Waveform
PWM
PWM
PWM
FM
PWM
PWM
PWM
PWM
L
0 to 10V,
[FM] output value
B081
C27=00, 01, 02, 04, 05, 06, 07
t
Selects FM type output
FM TH
H O2 AM
AMI PLC
P24
L O OI
Full Scale Value
0 – Max. frequency (Hz)
0 – 200%
0 – 200%
0 – Max. frequency (Hz)
0 – 100%
0 – 200%
0 – 100%
0 – Max. frequency (Hz)
FM TH FW
H O2 AM
AMI P24 PLC CM1
O OI
+ –
1 mA
t
= -- -
T
= [FM] terminal 8-bit gain setting
FW
CM1