Analog Output Operation; [Fm] Terminal; Pwm Signal Type - Hitachi L300P Series Instruction Manual

4–54

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, or other parameters to the controller to confirm actual operation. 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
03 Output frequency
C027 04 Output voltage
05 Input electric power
06 Thermal load ratio
07 LAD frequency
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
0 V
T
Period T = 6.4ms constant (156 Hz)
Analog/digital Output
D GND
See I/O specs on page 4–8.
Description Waveform
PWM
PWM
FM
PWM
PWM
PWM
PWM
L
0 to 10V,
[FM] output value
B081
C27=00, 01, 04, 05, 06, 07
time
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 – 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