Difference between BL and SV commands?

[Shizzlemah]

Guys,
Giving the Fadal a thorough preventative maintenance runthrough next week and wanted to check/verify the backlash settings.

The BL command shows current info, around 4 or 6 tenths, for 3 regions of X and Y, and one value for Z.

The SV command looks like it takes information inch by inch.... And my values are all zero.


I understand how to check/set backlash "BL" but do I need to worry about SV ? Is that only for ballscrew comp (like a laser dealio?) Can I measure that with a 50u dial indicator and a set of grade AA gage blocks ?

Thanks!

[Neal]

Shizzlemah--
The BL is for the backlash which repsents the mechanical slop in the drive system. The SV is for the survey. This is the correction compensation for any error in the lead of the ball screw thread. If you are trying to hold any close tolerence this is very important.

Neal

[Shizzlemah]

Gotcha, it has been a while since I've done a survey and that was on an ancient controller.

I should set BL first then measure the survey data ?

And for a survey measurement, the screw only moves in one direction, correct? So I don't keep revisiting backlash on top of screw lead errror?

Thank you

[Neal]

It really doesn't matter which you do first. Perodicaly you should verify your backlash. The survey is best done with a laser. A mechanical standard with ground blocks at 1" intervals is what we used to do. The laser is much superior. Since most people do not have the Laser equuipment, there are outside people that do that. Our Field service people do this operation frequently.
Neal