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No. 99MBC071A
d. When the circuit has the same specifications as described on the previous pages and controls
alternating current devices for signaling a –NG (assuming that the relay’s sensitivity is
50mA).
8
K
Load
R1
R2
0V
-NG
COM(OUT)
COM(OUT)
Connector pin No.
17
35
D1
+24V
K
(B)(A)
Q1: 2SA953, etc.
R1: 10KΩ
R2: 4.7KΩ
D1: Switching diode (100 to 200mA): Model 10D10 (Manufacture: Nihon Inter)
Q1
NOTE 1. Always use a shielded-wire cable as the I/O cable, and positively ground the
shielding wire net to the connector casing. If the cable does not have a shielding
net, the system may experience electrical interference resulting in operation
errors. Or, high frequency electromagnetic wave will be emitted from this system
and interfere the electrical equipment such as TVs, etc.
2. Observe the following precautions when relays are used for control circuits. Use
the following diagram when designing the control circuit.
a. Several kV of current may be induced the moment the relay is turned OFF,
which may cause relay-driven components to be damaged. Or, the induced
voltage may cause the system to malfunction. Always insert protective compo-
nents such as diodes in the circuit.
b. To drive equipment that operates on alternative current, always implement a
protective circuit (spark killer) to protect the relay contacts. In general, if the
current load is caused by induction, add protective circuit (A) or (B).
c. Refer to the manual of each relay for selection. It describes the method of
calculating the protection circuit (or selection of protective parts) depending on
the load.
