Output Wiring Precautions; Output Short-Circuit Protection; Transistor Output Residual Voltage; Output Surge Current - Omron CJ2 CPU UNIT User Manual

5 Installation

Output Wiring Precautions

Output Short-circuit Protection

If a load connected to the output terminals is short-circuited, output components and the printed cir-
cuit boards may be damaged. To guard against this, incorporate a fuse in the external circuit. Use a
fuse with a capacity of about twice the rated output.

Transistor Output Residual Voltage

A TTL circuit cannot be connected directly to a transistor output because of the transistor's residual
voltage. It is necessary to connect a pull-up resistor and a CMOS IC between the two.

Output Surge Current

When connecting a transistor or triac output to an output device having a high surge current (such
as an incandescent lamp), steps must be taken to avoid damage to the transistor or triac. Use either
of the following methods to reduce the surge current.
Method 1
CS/CJ-series
PLC
Add a resistor that draws about 1/3 of the current consumed by the bulb.
Method 2
CS/CJ-series
PLC
Add a control resistor as shown in the following diagram.
5-38
L
OUT
R
COM
R
L
OUT
COM
+
+
CJ2 CPU Unit Hardware User's Manual