(1)
Safety Precautions
(Read these precautions before use.)
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: and .
Depending on the circumstances, procedures indicated by may also cause severe injury.
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
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.
• 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 service power supply for sensors 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.
• Make sure to ground the shield wire or shield of the shielded cable connected to a special analog input adaptor or
special analog extension block at one point on the PLC.
However, do not use common grounding with heavy electrical systems.
Noise may cause malfunctions.
• Make sure to ground the shield wire or shield of the shielded cable connected to a special analog output adapto r
or special analog extension block at one point on the analog device side.
However, do not use common grounding with heavy electrical systems.
Noise may cause malfunctions.
• Install module so that excessive force will not be applied to the power connectors or terminal blocks.
Failure to do so may result in wire damage/breakage or PLC failure.