500 Overtravel +X

Hello,

I've got a johnsford shv-1000 with Fanuc 18i controls.

I can home it in after holding p+can on boot up.

After homing all axis, any movement more than .0196 (absolute) in the +x direction will trip the 500 overtravel +x alarm.

I've swapped the limit switches with a spare from another machine and tested voltage on them. They are working as intended.

Parameter 1326 is 500. I can increase this value and continue to hit soft overtravels based on the value.

I've compared the current parameters to the original that were on the machine back in 2009 when we bought it and the 1300 parameter and 1326 and 1327 have not changed between the two databases.

So why after all this time is this overtravel an issue? Is it safe to increase this parameter until it looks right on the +x axis position? If so how far should the soft overtravel be from the hard over travel dog. It's 40" in the x axis.

I'm actually looking at all my soft overtravel values in 1326 and 1327 and it appears this machine would not have been operating with in these values at all. I'm 100% positive parameter 1300 bit#2 has not been changed since we made the back up parameters. Any axis I move except z+ hits the hard overtravel before a soft. As if they were disabled until a few days ago when this overtravel became an issue. Should I go ahead and calculate soft overtravels for these axis? I'm worried this is not the resolution to the original problem that caused all of this.

Quote:

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Originally Posted by BiglyBigZ

Hello,

I've got a johnsford shv-1000 with Fanuc 18i controls.

I can home it in after holding p+can on boot up.

After homing all axis, any movement more than .0196 (absolute) in the +x direction will trip the 500 overtravel +x alarm.

I've swapped the limit switches with a spare from another machine and tested voltage on them. They are working as intended.

Parameter 1326 is 500. I can increase this value and continue to hit soft overtravels based on the value.

I've compared the current parameters to the original that were on the machine back in 2009 when we bought it and the 1300 parameter and 1326 and 1327 have not changed between the two databases.

So why after all this time is this overtravel an issue? Is it safe to increase this parameter until it looks right on the +x axis position? If so how far should the soft overtravel be from the hard over travel dog. It's 40" in the x axis.

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Where is X0 on your machine? Table centre or extreme X plus direction? Btw. 0.0196" is almost half a millimeter, or 500 in parameter 1326 ?

Usually on Fanuc, when referenced the display shows the axis reference positions from the parameters. What does your display show after reference?

Quote:

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Originally Posted by BiglyBigZ

I'm actually looking at all my soft overtravel values in 1326 and 1327 and it appears this machine would not have been operating with in these values at all. I'm 100% positive parameter 1300 bit#2 has not been changed since we made the back up parameters. Any axis I move except z+ hits the hard overtravel before a soft. As if they were disabled until a few days ago when this overtravel became an issue. Should I go ahead and calculate soft overtravels for these axis? I'm worried this is not the resolution to the original problem that caused all of this.

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The axis soft limit value is between reference point and the emergency overtravel switches (if present). These days these are soft limits with no switches at all, reference is found by driving to a hard end stop, then off again to the reference offset position.

The zero offset parameter to correct the zero point found by using a dial test indicator at the table centre in X/Y, with or without limit switches.

If the reference position with zero offset is too close to the soft limit, you can get overtravel errors after reference.

So only work out the soft limit parameter value after correction of the zero points.

x0 is extreme x plus direction. Thank you for your insight.

I believe it's sorted out. Was able to run a program overnight with no crashes or alarms.