Hitachi SJ300 Series Input Filter, Input Terminal Signals

4–59

SJ300 Inverter

Analog Input Operation

Input Terminal Signals

The SJ300 inverters provide for an external analog
			H		O2		AM		FM
input to command the inverter frequency output
value. The analog input terminal group includes		L		O		OI		AMI
the [L], [OI], [O], [O2], and [H] terminals on the	A GND
control connector, which provide for Voltage [O]
	+V Ref.
and [O2] or Current [OI] input. All analog input
signals must use the analog ground [L].
	0—10V input
If you use either the voltage or current analog
input, you must select one of them using the logic	-10 / 0 / +10V
input terminal function [AT] analog type. If
terminal [AT] is OFF, the voltage input [O] can	4—20mA input
command the inverter output frequency. If terminal
[AT] is ON, the current input [OI] can command

the inverter output frequency. The [AT] terminal function is covered in “Analog Input Current/ Voltage Select” on page 4–26. Remember that you must also set A001 = 01 to select analog input as the frequency source.

O2

1

O

Frequency

0

A005

A001=01

OI

1

1

Terminals

1

source setting

O

0

(Keypad)

Frequency setting

0

0

AT

H

O2

AM

FM

1

V – I select

L

O

OI

AMI

OI

4-20 mA

AT=ON

A005=00

O2

-10 / 0 / +10V

+ –

AT=ON

A005=01

O

+ –

0 – 10V

AT=OFF

L

Input Filter

Parameter A016 adjusts an analog input sampling filter that evenly affects all analog inputs

shown above. The parameter range is from 1 to 30. Before increasing the filter setting, we

recommend trying to find the cause of input analog noise. Check for the following:

•Look for nearby high-current wiring—avoid any parallel runs to the analog signal wires

•Check the impedance between the chassis grounds of the inverter and the analog signal source equipment—a good connection will have a low impedance

•Check the analog signal ground impedance from the inverter to the analog signal source

•Avoid ground loops... measure the current (or voltage drop) on the chassis ground and signal ground connections; the ideal value is zero

After taking steps to minimize the analog signal noise sources, increase the filter time constant (A016) until the motor output frequency (when commanded by analog inputs) becomes stable.

Operations Monitoring and