External Wiring Precautions - Mitsubishi FX3U SERIES User Manual

FX Series Programmable Controllers
3U
User's Manual - Hardware Edition

12.4.2 External wiring precautions

1. Protection circuit for load short-circuits
A short-circuit at a load connected to an output terminal could
cause burnout at the output element or the PCB. To prevent
this, a protection fuse should be inserted at the output.
2. Micro current load
The PLC's internal Triac output circuit is equipped with a turn-
off C-R absorber. When connecting a very low current load of
"0.4VA/100V AC or less, or 1.6VA/200V AC or less", please
connect a surge absorber parallel to the load.
Select the rated voltage of a surge absorber that is suitable for
the load being used. Refer to the table below for other
specifications.
Item
Static electricity capacity
Resistance value
Reference
Manufacturer
Okaya Electric Industries Co., Ltd. CR-10201
3. Interlock
For loads such as forward/reverse contactors, etc., where a
hazardous condition
simultaneously, an external interlock should be provided for
interlocking the PLC's internal programs as shown to the
right.
4. In-phase
PLC output contacts (*) should be used in an "in-phase"
manner.
Standard
Approx. 0.1µF
Approx. 100 to 200Ω
Model name
could result if switched
12 Output Wiring Procedures
12.4 External Wiring for Triac (SSR) Output Type
Load
Fuse
Micro current load
Manufacturer
Rubycon Corporation 250MCRA104100M B0325
Inter-
lock
ON
PLC output
element
Bad
Good
Y
COM1
PLC
Surge
absorber
Model name
Limit of normal
rotation
Normal
rotation
Reverse
rotation
Limit of reverse
rotation
*
*
*
*
221
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