Mitsubishi Electric MELSEC FX Series User Manual page 3

Before installation, operation, maintenance or inspection of this product, thoroughly read through and
understand this manual and 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
injury. In any case, it is important to follow all usage directions. 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 using.)
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
Reference
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117
133
166
180
217
238
276
340
Reference
.
94
117
133
166
180
217
238
276
340