A GND Analog/digital Output
See I/O specs on page 4–6.
H

4–30

Analog and Digital Monitor Output

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

O OI L FM CM2 12 11

Operations and Monitoring

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.

Func.

Code

Description

Waveform

Full Scale value

 

 

 

 

 

 

 

 

 

 

 

00

Output frequency

PWM

0 – Max. frequency (Hz)

 

 

 

 

 

C_23

01

Output current

PWM

0 – 200%

 

 

 

 

 

 

02

Output frequency

FM

0 – Max. frequency (Hz)

 

 

 

 

 

PWM Signal Type

The pulse-width modulated signal at terminal

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

H

O

OI

 

L

FM

CM2

12

11

 

[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

 

 

 

 

 

 

 

 

 

 

 

 

0 to 10V,

 

 

 

 

 

 

 

 

 

 

 

 

voltmeter.

 

 

 

 

 

 

 

 

 

 

 

 

 

1 mA

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

The signal characteristics of terminal [FM] in PWM configuration is shown below:

 

 

 

 

Pulse-width modulation (analog)

 

 

t

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

[FM] Output = ---

[FM]

 

 

 

 

 

 

 

 

t

 

 

 

 

 

 

 

 

 

 

T

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

10V

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

C_23 = 00

Inverter output frequency

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Inverter output current

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

0V

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

C_23 = 01

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

PWM scale factor

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

B 81

 

 

 

 

 

 

T

 

 

 

 

T = 4 ms

t

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

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.