Need Help!- Fanuc OT-B

[newc]

I have a Takamaz Vikturn with OT-B control. Spindle commands seem to be getting stuck in the buffer. All other commands having to do with axis movements work fine, but when I give it an M03 or M04 the command executes, but the control does not move on. ????

[jdeere4250]

sar spindle speed arrival is not coming to nc.
which spindle drive unit?
is the drive also fanuc ?
which part number?

[newc]

Thanks, jdeere, but it is not a drive problem, it is in the controller. RPMs indicate ok on screen. It turns out that M-codes and T-codes make the brain hang up. The program will not step on after a T or M call, either in AUTO or MDI.

[andyb4]

This may point to a stuck switch somewhere on the machine. Even though the function has actually finished, ie. speed ok, the control will not finish the block if a switch is in the wrong position. It is an input back to the control from the machine that it is looking for. Hope this helps

[jdeere4250]

need to look up m, s, or tfin to see what is hanging her up.
do you have otb maint manual?

[guhl]

This info was on forum already

when the CNC executes an M-code in the program, it sends the BCD code for that M-code to the PMC using two bytes (16 bits) in BCD format, then turns on a "strobe" bit called "MF". The PMC is then supposed to decode those two bytes of BCD data to determine what the M-code is, then execute that M-function on the machine, then reply to the CNC with the "finish" signal (a G-register flag) called "FIN". When the CNC gets the FIN signal from the PMC, it knows that the PMC has finished executing the M-function and it will continue with the next block of the program.

See PDF

Check diagnostic parameter 120 bit 3 (forth from the right)

[newc]

Thanks, guys
andy, you are sort of on the right track, the machine is looking for an "I'm done" signal, but it is not a mechanical problem. jdeere, you took it a little further, and guhl, your info is very good.
Diag. 120.3 is always 1, so I'm not sure what that is supposed to be telling me. 120.2 toggles when I push "cycle start" button. Half the time the spindle doesn't turn when I feed it an M03, and even when it does turn, it doesn't realise it, and the control hangs up. Same thing with T commands.
G00 and G01 work just fine. It seems to only be a problem with M and T commands........

[stevo1]

Do you have a door interlock or an unclamped chuck? This will hang the control on the M3, M4 commands as well.

Stevo

[newc]

No, Stevo, it is not a mechanical problem. The machine was running, making parts, and it just began to hang up on a M03 call. I found that tool change commands hang it up the same way. So M commands and T commands seem to get caught halfway through - other commands execute fine.

[andyb4]

M, S, T, and B codes are looked at the same way by the control. I had a machine with a 6T control that would act the same way. The problem was with a switch on the pallet changer being faulty (electrically) and the machine would hang up on any M, S, T, or B code. The switch doesn't necessarily need to be related to the operation you are trying to do. The machine will execute the command but not the block. This was a frustratring problem for sure. If your tool changer hangs up at the same spot all the time, I would look at the swith for that funtion. It may be OK for one tool change, then open or close as the case may be, sometime when it isn't being used.

[newc]

Thanks, andy, you never know - could be something like that. I will look at all the switches, worn wiring, etc. My diagnostic 700.0, which is the m, s, t complete signal, does change from 0 to 1 and then hangs there. I'm not sure if it is supposed to go to 1 briefly and then reset, or what....

[gbowne1]

Quote:

M, S, T, and B codes are looked at the same way by the control. I had a machine with a 6T control that would act the same way. The problem was with a switch on the pallet changer being faulty (electrically) and the machine would hang up on any M, S, T, or B code. The switch doesn't necessarily need to be related to the operation you are trying to do. The machine will execute the command but not the block. This was a frustratring problem for sure. If your tool changer hangs up at the same spot all the time, I would look at the swith for that funtion. It may be OK for one tool change, then open or close as the case may be, sometime when it isn't being used.

End Quote

Well, That's also why it pays to do a little maintenance and always make sure any hardware is working properly.. if not repair or replace any faulty items. Sometimes those electromechanical switches really mess with things.