IDEC FC4A-C10R2 User Manual page 109

Contact Protection Circuit for Relay and Transistor Outputs
Depending on the load, a protection circuit may be needed for the relay output of the
tection circuit from A through D shown below according to the power supply and connect the protection circuit to the out-
side of the CPU or relay output module.
For protection of the transistor output of the
tor output circuit.
Protection Circuit A
Output Q
C
R
COM
Protection Circuit B
Output Q
COM
Protection Circuit C
Output Q
COM
Protection Circuit D
Output Q
COM
MicroSmart
This protection circuit can be used when the load impedance is
Inductive Load
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
Inductive Load
circuits.
R: Resistor of approximately the same resistance value as the load
R C
C: 0.1 to 1 µF
or
– +
This protection circuit can be used for DC load power circuits.
Inductive Load
Use a diode with the following ratings.
Reverse withstand voltage: Power voltage of the load circuit × 10
Forward current:
– +
This protection circuit can be used for both AC and DC load power
Inductive Load
circuits.
Varistor
– +
or
« FC4A M
modules, connect protection circuit C shown below to the transis-
S U ' M
ICRO MART SER S ANUAL
3: I
NSTALLATION AND
MicroSmart modules. Choose a pro-
More than the load current
»
W
IRING
3-15