[jorber]

I've been struggling :boxing: with a Bridgeport VMC machine with a Fanuc 11M controller for a long time.
the motherboard was changed because apparently it had a problem (not booting at all),
after the change the machine boots but shows an alarm as if all limit switches were tripped.
my guess was that the IO module had a fail, then replaced it but no change.
finally I read that i have to check the optic fibers and if there are the IR signals.
i test that using an infrared camera and could see a solid IR lights coming out from motherboard and IO module. Now I don't know what else to check.

Jorge B.

[memoryman]

when posting, give complete information, please.
What are the alarm #s? Did you look in the diagnostics to see the input signal states? Is there a ladder? Does it show the signals (ot) active?

[Al_The_Man]

Is there a 24v supply dead? is 24v present on the I/O board the O.T. switches are input to?
Make sure the fuse on the I/O board is OK.
See similar post http://www.cnczone.com/forums/fanuc/...uit_limit.html
Al.

[jorber]

when posting, give complete information, please.
What are the alarm #s? Did you look in the diagnostics to see the input signal states? Is there a ladder? Does it show the signals (ot) active?

There is voltage even in the module i can see the leds change when any of the limits is pressed. The alarms are only for the limits OT +X - X +Y - Y +Z - Z.
What is happening is that these signals are not getting in the motherboard
have to look for the fuses I think I already did but going to double check

[memoryman]

It is possible that the machine is wired with all ot switches in series (very rare); check the machine wiring diagrams.
You should be able to see inputs in the diagnostics. Do you see a response when an ot is activated?

[jorber]

It is possible that the machine is wired with all ot switches in series (very rare); check the machine wiring diagrams.
You should be able to see inputs in the diagnostics. Do you see a response when an ot is activated?

I was checking what you Al and Memoryman told me to check, What I found is that the 24 V are present on the I/O module, i tested the fuses and all are ok, in the diagnostics and in the ladder when I press any button on the operators panel I can see that is been activated(cycle start, dry run, etc), different happens when I press any of the limis switches, I only can see on the module leds but neither in the diagnostics nor in the ladder, they are seen as if were not pressed. I am still thinking that is a problem of comminication between the I/O and the Master PCB.

[memoryman]

It looks that the communication is done through an optical cable; it is very unlikely that there is a problem with that.
Do you have a ladder diagram? Machine electrical? There is probably a common wire/signal to the limit switches. Look there.

[Al_The_Man]

Try hold opening the contact on one of the switches (N.C.?), measure the voltage between the contacts, normally the inputs are sourced and sunk to ground through the switch, either way, you should see 24v present at one point and go to zero when you close the contact.
Al.

[jorber]

Try hold opening the contact on one of the switches (N.C.?), measure the voltage between the contacts, normally the inputs are sourced and sunk to ground through the switch, either way, you should see 24v present at one point and go to zero when you close the contact.
Al.

I did that on the module and is exactly as you describe, see picture

[Al_The_Man]

I had thought you had a remote I/O board, but I see you have a remote PLC rack.
Usually with these systems even though the LED lights, which shows the input is toggling, it is just a local indication, it does not guarantee that the signal is getting any further.
Does it only apply to inputs on that one card? and do the other cards register and show I/O in the diagnostics? If so, it means the PLC is communicating.
Al.

[drdos]

I assume this all worked before the motherboard was replaced (Before the non boot issue) That being said looks like you have a bad motherboard. It fixed the booting issue and gave you an I/O issue. Might want to replace the motherboard again.

[jorber]

thanks drdos, that's what I suspect is happening. I am trying to enclose the problem to make sure what would be the solution

I assume this all worked before the motherboard was replaced (Before the non boot issue) That being said looks like you have a bad motherboard. It fixed the booting issue and gave you an I/O issue. Might want to replace the motherboard again.