Mitsubishi E60/E61 alarm: CNC/drive or I/O communication error

Mitsubishi/MELDAS reports communication failure between CNC, drive or I/O modules. It is an alarm from the PLC/machine area, and in the catalog it is listed as “CNC/drive or I/O communication error”. On the machine you notice it like this: Machine is not ready, Module does not communicate, Alarms at start-up.

On the shop floor it almost always comes from one of these causes: Communication cable, Module without power, Network/station configuration, Electrical noise. Rule out the most likely one on your machine first, before touching parameters or swapping anything.

Reset/reboot after recovering communication. Resetting without fixing the cause first only hides the problem: Mitsubishi E60/E61 trips again and, in the meantime, you keep working with the machine in bad shape.

With the machine stopped and in a safe state, start with these checks: Write down complete code, Check module LEDs, Do not change addresses without a backup. That alone will tell you whether it is the program or whether you need to raise a maintenance job.

With Mitsubishi E60/E61 active, avoid this: Do not bypass safety devices, Do not manipulate energized electrical cabinet, Do not continue producing if the alarm reappears. Skipping any of these points is what turns a minor stop into an expensive breakdown.

Always, if it persists after a restart. If you are not sure how far it goes, stop the machine and report it: a repeat alarm always works out cheaper than a crash.

It is critical: there is a real risk of damage to the machine, the tool or a person. Leave the machine stopped, do not keep resetting it to see if it goes away, and call maintenance before producing again. Guidance reference. Always confirm the full text in the exact machine/control manual.