Servo Gun "Gun Attach" stopping program

[smiley]

We are currently using around 300 servo guns but have a recurring problem with one. While it is running the gun attach program (it runs 2 guns on tool changers) the program stops, no faults nothing in the error log etc, and it recovers off the teach pendant pretty much straight away. Any ideas?

[Stormtrooper]

Sounds to me that you might have a problem with the gun changer module, maybe the internal connections are not being made correctly.
Check that the gun changer is closing correctly - any gap condition could lead to a problem. If the robot is running in automatic mode it is following the path programmed, but when it is switched in teach mode the first thing that happens is the servo drives will dis-engage and the robot will drop slightly, maybe enough to make the safety contact and allow you to operate the robot in teach mode.

[Professor_J]

I doubt it's a problem with the tool changer itself, presumably you'd  be getting alarms (DTERR etc for pulse coder connections or move/stop errors for power/brake connections) if this were the case..

We have a few tool changers and one of our robots has the same symptom as yours.. We are yet to solve it, in our case the only peculiar thing about the problem robot is that the pulse coder cable still goes directly to the gun servo amp instead of through the Fanuc Brake unit (it has pulse coder sockets etc on it).. All of our other tool changer ones go through the brake unit... Not sure if this is related to our fault and even if it is, not sure if it's relevant to your fault..

[Vlad]

i think it should be better to add a all of above, done as soon the problem happends...

bye
Vlad

[[fanucker]]

Gents, not possible that robot has a fault that is not logged, thus Vlad is right.
AoA when problem occurrs is best way to find it (in ERRALL.LS or HIST.LS)

Tip: If is R-30iA with v7.30P/xx with xx>16 you can press FCTN, next twice, Diag Log and send to local Fanuc Representative if Hist, errall and LOGBOOK.LS are not enough.

[bnradams]

We have several tool changing robots in our facility.  I beleive the pause you are seeing is the controller establishing a link with the pulse coder and doing pulse count checks etc.  In order to squeeze a few seconds out of our program run time, we used the "RUN" gun attach instead of "CALL" Gun attach.  the "RUN" statement allows the gun attach command to execute without the controller waiting for it to complete.  While the gun attach is running in the background, we continue motion on the major 6 axis to approach the work without a pause.  The only drawback seams to be that you cannot use the gun until the Gun Attach is complete.  If you try to initiate gun motion before the Gun Attach is complete you fault (I dont remember the exact fault code) but by the time you manually reset, the Gun Attach is complete.  In our application, we added a "WAIT $MOR_GRP[2].$SERVO_READY = 1" after the gun attach and motion toward work but before motion to use the axis.  It took a little playing arround to get the sub programs group masked correctly but this has worked for us.

[Professor_J]

Not sure about the original post by smiley but the issue we have with one of our robots is certainly not just the delay it takes to attach.. We also use "Run" to mimimise the cycle time impact but this is totally unrelated to the issue...

We normally just use a register to signal when the background attach has finished but I'll check out the variable listed below ($MOR_GRP[2].$SERVO_READY) as this may be good to use as an additional check.. Thanks