Mitsubishi FX3U SERIES User Manual page 3

Before installation, operation, maintenance or inspection of this product, thoroughly read through and
understand this manual and all of the associated manuals. Also, take care to handle the module properly and
safely.
This manual classifies the safety precautions into two categories:
Depending on the circumstances, procedures indicated by
It is important to follow all precautions for personal safety.
Store this manual in a safe place so that it can be taken out and read whenever necessary. Always forward it
to the end user.
1. DESIGN PRECAUTIONS
• Make sure to have the following safety circuits outside of the PLC to ensure safe system operation
even during external power supply problems or PLC failure.
Otherwise, malfunctions may cause serious accidents.
1) Most importantly, have the following: an emergency stop circuit, a protection circuit, an
interlock circuit for opposite movements (such as normal vs. reverse rotation), and an interlock
circuit (to prevent damage to the equipment at the upper and lower positioning limits).
2) Note that when the PLC CPU detects an error, such as a watchdog timer error, during self-
diagnosis, all outputs are turned off. Also, when an error that cannot be detected by the PLC
CPU occurs in an input/output control block, output control may be disabled.
External circuits and mechanisms should be designed to ensure safe machinery operation in
such a case.
3) Note that the output current of the 24V DC service power supply varies depending on the
model and the absence/presence of extension blocks. If an overload occurs, the voltage
automatically drops, inputs in the PLC are disabled, and all outputs are turned off.
External circuits and mechanisms should be designed to ensure safe machinery operation in
such a case.
4) Note that when an error occurs in a relay, triac or transistor output device, the output could be
held either on or off.
For output signals that may lead to serious accidents, external circuits and mechanisms should
be designed to ensure safe machinery operation in such a case.
• Do not bundle the control line together with or lay it close to the main circuit or power line. As a
guideline, lay the control line at least 100mm (3.94") or more away from the main circuit or power
line.
Noise may cause malfunctions.
• Install module so that excessive force will not be applied to peripheral device connectors.
Failure to do so may result in wire damage/breakage or PLC failure.
Safety Precautions
(Read these precautions before use.)
Indicates that incorrect handling may cause hazardous conditions, resulting in
death or severe injury.
Indicates that incorrect handling may cause hazardous conditions, resulting in
medium or slight personal injury or physical damage.
(1)
and .
may also cause severe injury.
Reference
Reference
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123
147
164
205
223
263
286
325
407