I enconuntered problem with one of CNC machine brand name Yang lather machine from Taiwan origin with Fanuc 0-i TB control.

When the machine has power up, an emergency alarm occurs which can't able be re-set, we found all signal in I/O diagnostic display page are missing. Button such as cycle start, feedhold etc has no signal in I/O diagnostic disply.

we have checked the flat cable connected from the I/O to operator panel which working OK, checked pin to pin and line to earth which is working OK.

we have decided to replaced the fanuc I/O board but after replacing the I/O board problem still exist. it could be the motherboard problem? or somewhere else?

Gents any idea?

Thanks,
Miles

Check if you have a pmc message. You must be able to see the ladder, can you do that? Is it active? (running)
Check if there are other I/O boards. It seems to me that there are more than just the one that you replaced. If there are other modules, check for blown fuses.

CNCMILES,

The YANG machines, normally has an button to POWER ON the machine and another button to MAKE MACHINE READY !!! The machines that has here in Brazil with 0TB has this button. Check that.

Best Regards,

Daniel

Hi Guys,

Thanks for your valued inputs.

The power ON button has been pressed and the machine was in NOT READY STATUS.

No input signal from X16,17,18,20,21,22 ( LK1 flat cable connected from I/O board to relay PCB Yang SML-12-001).

No input signal from X0,2,4,6,8 (LK3 flat cable connected from I/O board to operator panel)

No output signal from Y48,49,50 and 52 ( LK2 flat cable connected from I/O board to relay PCB Yang SML-12-001).

I've suspect that Relay PCB cuasing the problem? But this machine is already obselete in the market and the Yang machine builder already closed whcih difficult to find the replacement parts.

Could you please advise.

Many Thanks,
CNC Miles

Hello, Can you see the ladder? Is it active?

Hi Alex,
Yes, it is. The ladder is active.

Miles

If you have checked as follows:
1.DC power every output voltage
2.air break on or ff
3.CNC board has any alarm is lighted
4.servo unite has alarm.

If above is ok i suggest you display top part of pmc. normally top part of pmc is EMG button and Feedhold button.

you can check emg button and feedhold button diagnostic information.

You can also check overtravel limited switch signal by pmc.

Because EMG & overtravel signal are fix address in PMC.

If these signal are good or not good you can use a voltage signal (+24V or 0v) directly connecting socket pin of pmc.

if your pmc is running you will show some activities of PMC.

My past experients with Taiwan CNC machine with emergency alarm was 24VDC problem. It may be wire broken, relay no good or 24V power supply no good.

The problem could be in the master pcb located in the back of the display. There you can find a very small power supply wich could be broken. This is a 24VDC power supply.