Hitachi L300P - Manual (Page 184)

Analog Output Operation
Oper
ations
a
nd Moni
tor
ing
4–54
Analog Output Operation
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.
[FM] Terminal 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.
PWM Signal Type 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
Func. Code Description Waveform Full Scale Value
C027
00 Output frequency PWM 0 – Max. frequency (Hz)
01 Output current PWM 0 – 200%
03 Output frequency FM 0 – Max. frequency (Hz)
04 Output voltage PWM 0 – 100%
05 Input electric power PWM 0 – 200%
06 Thermal load ratio PWM 0 – 100%
07 LAD frequency PWM 0 – Max. frequency (Hz)
See I/O specs on page 4–8 .
D GND
Analog/digital Output
H O2 FM AM
O OI L
FW TH
PLC P24 CM1 AMI
H O2 FM AM
O OI L
FW TH
PLC P24 CM1 AMI
+ –
0 to 10V,
1 mA
0 V
time
[FM]
10V
T
t [FM] output value
t
T
--- =
Period T = 6.4ms constant (156 Hz)
Selects FM type output
= [FM] terminal 8-bit gain setting B081
C27=00, 01, 04, 05, 06, 07