Mitsubishi FX3U 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
• When executing control (data changes) to an operating PLC, construct an interlock circuit in the sequence program
so that the entire system operates conservatively.
In addition, when executing control such as program changes and operation status changes (status control) to an
operating PLC, thoroughly read the manual and sufficiently confirm safety in advance.
Especially in control from external equipment to a PLC in a remote place, problems in the PLC may not be able to
be handled promptly due to abnormality in data transfer.
Construct an interlock circuit in the sequence program. At the same time, determine the actions in the system
between the external equipment and the PLC for protection against abnormalities in data transfer.
• Make sure to include the following safety circuits outside the PLC to ensure safe system operation even during
external power supply problems or PLC failure.
Otherwise, malfunctions may cause serious accidents.
1) Above all, the following components should be included: 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 main unit detects an error during self diagnosis, such as a watchdog timer error, all
outputs are turned off. Also, when an error that cannot be detected by the PLC main unit 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 cases.
• Observe the following items. Failure to do so may cause incorrect data-writing through noise to the PLC and result
in PLC failure, machine damage or other accident.
1) 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.
2) Ground the shield wire or shield of a shielded cable. Do not use common grounding with heavy electrical
systems
• Do not apply excessive pressure to the power supply terminal block or CC-Link connection terminal block.
Excessive pressure may cause damage or error.
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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