Fanuc OT problem

[Skybrake]

I am repairing Kirloskar internal grinding machine with Fanuc OT control. Factory in which i am working got this machine about 5 years ago, but noone has worked on it because one axes was not moving. I repared axes about week ago. Now machine returns to zero position, works in JOG and MPG modes, both spindles ir turning. But problem is that i cant make it work in MDI mode. This is first time i am working with Fanuc controls, maybe i just dont now how exactly to work with machine? Example: i turn on the machine, retun axes to zero position, swich to MDI mode. I press M43, then INPUT and then CYCLE START. CYCLE START led blinks, but nothing happens. Documentation says that in this moment grinder work spindle must turn in low speed. There may be problems with parameters too. Maybe someone had similar problems?

About machine:
Kirloskar S-CNC internal grinder MK-IG-1250
Fanuc OTE control.

It is important to repair this machine as fast as i can but about this problem now i have no ideas...

[Al_The_Man]

On a grinder do you need to enter an S value and M3 or M4?
The fact the cycle start light up momentarily shows that the commmand completes and does not hang up.
Al.

[bob1371]

Can you view the ladder or status bits and check G4.3? That should be the Finish signal. If you can check this on the ladder just follow that and see why its not getting the finish signal.
Do you need to command a speed with the M43?
During this 5 years of sitting did the machine lose parameters?

Bob

[Skybrake]

Al - no work spindle does not need S parameter. I think. Commands for work spindle - M43 - work spindle low speed, M44 - work spindle high speed, M45 - work spindle off. And for wheel spindle there is only two commands - M80 and M81. On and Off. There is no frequency regulators for any motor, it can anly be on or off. Strange is that there is nothing about M3 command in documentation. But i have not tried to execute it, ill try.

Bob, you mean 4.3 in parameter window? Of course i'll check it. I have a PLC sowfware book too. Yes, parameters was lost, but in documentation they are written. Is they are parameters for exactly my machine its another question.ft

[Skybrake]

Thanks, bob, i found M FINISH signal in PLC software book and all logic that is about M43 command execution. In monday i'll check out the signals.

[Al_The_Man]

It is odd the M code completes, as normally an instruction like this has to wait for the spindle to indicate up-to-speed or running, if this does not occur, then the FIN signal is never seen and it hangs.
I think Bob is refering to the G4.3 (FIN signal) this is not a G code instrucion but a G register number/bit that can be seen in the diagnostic, these G resgisters are ones that are passed from the PMC (ladder) to the CNC side, ones coming back are F registers.
Al.

[Skybrake]

Machine is not hanging. I can try to execute another command after, for example, M43.
There is no sensors that monitoring spindle is up-to-speed as you sayed.
Yeah, I understood about G4.3 in diagnostics. But as i found into PLC software G4.3 is Magnetic Seperator Motor Overload. M FINISH is G120.3.

[Al_The_Man]

Generally the common method of up to speed does not require any sensors external to the drive it is an output from the spindle drive to the PMC that says the ramp up to speed has completed and should now be between 85% & 100% of commanded speed.
Al.

[Skybrake]

There is NO speed regulators at the spindle control circuit. Just a simple magnetic contactor that turns on or off from CNC board. And as i remember in the software there is no signal something like "spindle speed ready". Now i'll try to find what's going on with M FINISH signal. Thanks.

[Al_The_Man]

I guess I got confused, because you mentioned in an earlier post that you had two speeds, How do they do that if it is just a contactor pick-up, unless they run in star & delta?
If so there should be a ladder rung for each speed, triggered by the M code.
Which means the M code does not know or the FIN signal get confirmation wether the contactor is picked up or not, that may be why.
It is an unconfirmed FIN signal.
Al.

[bob1371]

Im with Al here, you will have to have something giving the MFIN signal. If its just a contactor then maybe they are using aux relays from the contactor? Monitoring the motor leads for amperage, or something to show the motor running?
Using M43 and M44 for high/low speed are you switching gears in a gearbox? If so it could be a switch showing that it changed gears. If not it should be as Al stated, a star/delta connection.
Be sure to post back what ya find.

Bob

[Skybrake]

Sorry yes there is two speeds for one spindle but they are switching with contactors. I mean there is no electronic regulators. It is something like star/delta. And there is no current monitoring as you sayed. No encoders on spindles.

But the problem is that both spindles is not turning at all after entering code.

OK, i'll check the M FIN signal tomorrow.