Data Link Procedure - Mitsubishi FX3U User Manual

FX -16CCL-M User's Manual
3U
9.

Data Link Procedure

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.
DESIGN PRECAUTIONS
• 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.
STARTUP AND MAINTENANCE
PRECAUTIONS
• Do not touch any terminal while the PLC's power is on.
Doing so may cause electric shock or malfunctions.
• Before cleaning or retightening terminals, cut off all phases of the power supply externally.
Failure to do so may cause electric shock.
• Before modifying or disrupting the program in operation or running the PLC, carefully read through this manual and the associated
manuals and ensure the safety of the operation.
An operation error may damage the machinery or cause accidents.
STARTUP AND MAINTENANCE
PRECAUTIONS
• Do not disassemble or modify the PLC.
Doing so may cause fire, equipment failures, or malfunctions.
For repair, contact your local Mitsubishi Electric representative.
• Turn off the power to the PLC before connecting or disconnecting any extension cable.
Failure to do so may cause equipment failures or malfunctions.
• Turn off the power to the PLC before attaching or detaching the following devices.
• Failure to do so may cause equipment failures or malfunctions.
- Peripheral devices, display modules, expansion boards and special adapters
- I/O extension units/blocks, FX Series terminal block and the special function units/blocks
- Battery and memory cassette
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9 Data Link Procedure