Mitsubishi FX3UC SERIES User Manual page 217

FX Series Programmable Controllers
3UC
User's Manual - Hardware Edition
8. Terminal Block Specifications and External Wiring
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
4) 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).
5) 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.
6) 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.
• Note that when an error occurs in a remote I/O unit, the output could be held either on or off.
For output signals that may lead to serious accidents, external circuits for monitoring should be provided.
DESIGN PRECAUTIONS
• Do not bundle the control line and CC-Link/LT connection cables together with or lay them close to the main circuit
or power line. As a guideline, lay the control line and CC-Link/LT connection cables at least 100mm (3.94") or
more away from the main circuit or power line.
Noise may cause malfunctions.
• Install the product so that excessive force will not be applied to peripheral device connectors, power connectors,
input/output connectors, CC-Link/LT interface connectors or CC-Link/LT connection cables.
Failure to do so may result in wire damage/breakage or PLC failure.
INSTALLATION PRECAUTIONS
• Make sure to cut off all phases of the power supply externally before attempting installation or wiring work.
Failure to do so may cause electric shock or damage to the product.
8 Terminal Block Specifications and External Wiring
1
2
3
4
5
6
7
8
9
10
211