(i)
Safety Precautions
(Read these precautions before using.)
Before installing, operating, maintenance or inspecting this product, thoroughly read and understand this
manual and the associated manuals. Also pay careful attention to handle the module properly and safety.
This manual classifies the safety precautions into two categories: and .
Depending on circumstances, procedures indicated by may also be linked to serious results.
In any case, it is important to follow the directions for usage.
Store this manual in a safe place so that you can take it out and read it whenever necessary. Always forward
it to the end user.
1. DESIGN PRECAUTIONS
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.
Reference
• Provide a safety circuit on the outside of the PLC so that the whole system operates to ensure the
safety even when external power supply trouble or PLC failure occurs.
Otherwise, malfunctions or output failures may result in an accident.
1) An emergency stop circuit, a protection circuit, an interlock circuit for opposite movements,
such as normal and reverse rotations, and an interlock circuit for preventing damage to the
machine at the upper and lower positioning limits should be configured on the outside of the
PLC.
2) When the PLC CPU detects an error, such as a watch dog timer error, during self-diagnosis, all
outputs are turned off. When an error that cannot be detected by the PLC CPU occurs in an
input/output control block, output control may be disabled.
Design external circuits and mechanisms to ensure safe operations of the machine in such a
case.
3) When some sort of error occurs in a relay, triac or transistor of the output unit, output may be
kept on or off.
For output signals that may lead to serious accidents, design external circuits and mechanisms
to ensure safe operations of the machine in such cases.
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Reference
• Observe the following items. Failure to do so may cause incorrect data-writing by noise to PLCs
and result the PLC failure, machine damage or an accident.
1) Do not lay close or bundle with the main circuit line, high-voltage line, or load line.
Noise and Surge induction interfere with the system operation.
Keep a safe distance of least 100 mm (3.94") from the above lines during wiring.
2) Ground the shield wire or shield of a shielded cable at one point on the PLC. However, do not
ground at the same point as high voltage lines.
• Install in a manner which prevents excessive force from being applied to the built-in connectors
dedicated to programming, power connectors and I/O connectors.
Failure to do so may result in wire breakage or failure of the PLC.
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