IDEC SmartAXIS FT9Z-1A01 User Manual page 67

Output Protection Circuit
When a motor, solenoid, or similar inductive load is connected, the life of the contact is shortened due to the inrush current and
counter-electromotive force acting on the load. Set up a protection circuit to prevent this from happening. Choose a protection
circuit from A through D shown below, according to the power supply, and connect the protection circuit to the outside of the
SmartAXIS.
For protection of the transistor output of the SmartAXIS modules, connect protection circuit C shown below to the transistor output
circuit.
Protection Circuit A
Output Q
COM
Protection Circuit B
Surge Killer
Output Q
COM
Protection Circuit C
Output Q
COM
Protection Circuit D
Output Q
COM
Inductive Load
C
R
Inductive Load
R C
or
– +
Inductive Load
Diode
– +
Inductive Load
Varistor
– +
or
S A XI S P
M AR T
This protection circuit can be used when the load impedance is smaller
than the RC impedance in an AC load power circuit.
R: Resistor of approximately the same resistance value as the load
C: 0.1 to 1 µF
This protection circuit can be used for both AC and DC load power
circuits.
R: Resistor of approximately the same resistance value as the load
C: 0.1 to 1 µF
This protection circuit can be used for DC load power circuits.
Use a diode with the following ratings.
Reverse withstand voltage:
Forward current:More than the load current
This protection circuit can be used for both AC and DC load power
circuits.
/ L U ' M FT9Y-B 1378
R O I TE SER S ANUAL
3: I
N STALLATI ON AN D
Power voltage of the load circuit  10
W
I R I N G
3-11