Proximity Switches, Sb stops BUT software runs on

[evan]

I've got a PRTalpha upgrade, using the latest version 3.3.18. In determining the distance from the home(0,0) position to the activation point of either the X or Y axis proximity switch using the (K)eyboard control, the limit switch stops the carriage, BUT the readout goes on for another couple of inches. Then when I MH or JH it's off by the over run in the readout even though the steppers never actually went that distance to begin with...
I've checked the conections, the gears are snug on the steppers...
Any ideas????

[fleinbach]

I'm not sure but I had a simular problem back on July 31st with the Z axis continuing to run when setting software table limits. This was in version 3.2.10 It happened during a slightly differant operation but the counter continuing to run after the tool stopped was the same.

This was what I documented back then and I thought it was corrected in the next versions, but I'm not positive since I've never set table limits yet.

" When using UR command everything works ok until I manually change the Z limit to anything new. At that time the Z limit can become something entirely different than what set. It seems that it also affects the X or Y axis sometimes. But so far it is consistent on the Z."

[paco]

Evan-

What is your VN first parameter?
What is your SF setting?
At what set speed do you "move" to activate the switches?

I believe this issue should be adress to support... I just duplicate the problem on my tool as going back and forth on the X switche; I had to do it a couple of time to get it to failled on the reading/display... look like it happen when SF,0; cannot duplicate when set to SF,1... my table limits are changed from the defaults; but did'nt seem to make a difference to what they are set... I must add that the control software loose communication with the control box if I keep testing the trigger after duplicating the problem once... even crash on a few occasions... I run 3.3.18 Alpha too...

[paco]

Back about this; I have duplicate the problem with SF,1 but with a VL limit that is behond the switche location/activation... in other word, the problem seem to be about the "triggering" of the limit switches... again I had to go back and forth a couple of time on the switche to duplicate the problem... I was'nt able to duplicate this on the Y thought I tested mostly on the X... what about you Evan; is it doing it every time or occasionnaly? I suggest you to go very slowly to get the reading for your switches location until the problem is solved... and reload SB3 if it does it again...

[evan]

Just got back in the shop. (It's still early out here on the left coast.) I'm going to try it all again before I call Tech. I will check VN and SF...
woke up thinking the Move speed might be a little high 8.(Paco great minds think alike) Last night it was it was doing it pretty much every time on both the X & Y. I'll lower it to 6 or 5 and try again, then I'll call Tech.

[evan]

Oh, and THANK YOU for your info and responses.

[paco]

Thought I believe it's better to "trigger" a such device at slow set speed, I was doing it at 10"... for testing... but when going back and forth, I was probably hitting it at pretty slow... keep us inform of your findings Evans!

[evan]

I lowered the Move speed down to 6 and was unable to repeat the problem, although if I raise the Move speed back up to 8 I get the same problem again.
I'll just have to remember to lower my move speed down to 6 or lower when I Home the Bot. Better yet I guess I could write it into the program.

Haven't heard back from Tech but I just emailed them since it's not such an urgent promlem.

[paco]

Really!? I'll test that too soon to see... That's the way to go about non-urgent problem(s); anyway they will respond quite fast... you'll see!

[evan]

Tech says best results for this application is max Jog speed of 4 and max Move speed 1 for high accuracy.
Makes sense. I guess if you hit your prox switches by accident at higher speeds you might want to recalibrate the machine because there is a chance that the steppers will be out.

[paco]

Still; the control software MIGHT have a bug since the problem is intermitent... I have noticed that if I hit the switches fast the tool may travel at different distance each time (a few thousands) but sometime it phycicaly stop at hitting the switche but the display continue on to a kind of rampin' down to up to a few inches?!?!?!?

[evan]

That's the problem I had having also. Although at the slower speeds I haven't been able to duplicate it. However I do agree with you that there probably is a bug in the control software because it shouldn't happen at any speed, when the carrage stops the counter should not be getting any feed back and there for should not continue to count!
I'm sure they'll get it worked out.
In the mean time I'll try not to let it drive me

[paco]

I have "forwarded" the thread to support yesterday...