Analog Input Operation - Hitachi SJ7002 Series Instruction Manual

Analog Input Operation

Input Terminal
Signals
Input Filter
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SJ700 inverters provide for an external analog
2
input to command the inverter frequency output
value. The analog input terminal group includes
the [L], [OI], [O], [O2], and [H] terminals on the
control connector, which provide for Voltage [O]
and [O2] or Current [OI] input. All analog input
signals must use the analog ground [L].
If you use either the voltage or current analog
input, you must select one of them using the logic
input terminal function [AT] analog type. If
terminal [AT] is OFF, the voltage input [O] can
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
Voltage Select" on page 4–24. Remember that you must also set A001 = 01 to select analog
input as the frequency source.
O2
1
O
0
OI
1
O
0
FM
H O2 AM
AMI
L O OI
OI
O2
+ –
O
+ –
L
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.
A GND
+V Ref.
0—10V input
-10 / 0 / +10V
4—20mA input
A005 A001=01
1
Terminals
1
0
(Keypad)
0
AT
V – I select
1
4-20 mA
AT=ON A005=00
-10 / 0 / +10V
AT=ON A005=01
0 – 10V
AT=OFF
4–63
SJ700 Inverter
2
FM
H O2 AM
AMI
L O OI
"Analog Input Current/
Frequency
source setting
Frequency setting