[cevyil]

We have Mori-Seiki machining center with Fanuc 15M. The machine has no input signal. I have checked NC I/O connection unit serial numbered A20B-1003-0240.
It have a 1.6A broken fuse, and i replaced the fuse but when i turned on the machine the fuse broken again . Then i plugged out all I/O connection unit sockets(not plugged out +24v socket), i replaced the fuse and turned on the machine the fuse is good. Do i have a short circuit on my I/O connection unit or my machine equipments(switches,button,proximity switches)?
Best Regards.

[Rich 72]

I guess I'm a little confused. It sounds like you have a short some where, if it was me I would unplug all the I/O and plug in each I/O card to see where the short might be. Then remove each wire from the card to determine which wire or circut is causing the problem. It is probably a push button, switch, or maybe a cable that has been cut. I have seen sensors that have failed cause this kind of problem

[cevyil]

Thanks for your fast reply.I will investigate all I/O sockets.
Best Regards.

[Al_The_Man]

You will probably find it is an active device that requires 24v and common such as a proximity switch, a passive device such as a push button that sinks to common does not cause any ill effects as the only two connections are usually the input and common.
Although if the push button has a lamp on it, you will have common for the PB and 24v for the lamp in close proximity to each other.
Also look for pinched cables on the 24vdc, as mentioned, plugging one Honda plug in one at a time should pin it down to the general area.
Al.

[cevyil]

Thanks for your reply. I will investigate your instructions.
Best Regards.