Home/Limit advice, please

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6 years 4 months ago #171084 by bbsr_5a
Replied by bbsr_5a on topic Home/Limit advice, please
you can set the numbers to your need
even REF to the right and stop in center
Code:
[AXIS_1] TYPE = LINEAR HOME = 235.0 MAX_VELOCITY = 20.0 MAX_ACCELERATION = 120.0 STEPGEN_MAXACCEL = 200.0 SCALE = 100.0 BACKLASH = 0.1 FERROR = 1 MIN_FERROR = .25 MIN_LIMIT = -235.0 MAX_LIMIT = 236.0 HOME_OFFSET = 474.000000 HOME_SEARCH_VEL = 3.000000 HOME_LATCH_VEL = 3.000000 HOME_FINAL_VEL = 5 HOME_SEQUENCE = 2

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6 years 4 months ago #171266 by blockbuffer
Thanks, gents!

Seems stable now, and it *might* be ready to move on to cutting air - here's an update. Any thoughts?

One of the issues I was having earlier was that I'd test moves in MDI and not get consistent behaviors. I was *assuming* that moves would be incremental. Nope. I think there may be a random-mode-default generator in the background. :-) Once I started setting G91 explicitly in MDI, that settled down and I started to get the incrementals that I expected.

The mill currently passes the simple test of moving a given distance on an axis, and then returning the same distance, to its hard stop. This for all of XYZA.

I did take advice to just bump the axes at the hard stops and pass on using switches. That's the advice in the wiki for hobby mills as well - just took me a while to find it. Yes, the steppers make some noise if they stall, but apparently, no real harm done.

This is a Taig 2019CR-ER mill, so the table's a bit larger than the original.

X Axis
The motor and its stop are on the right side of the table, so from the stop position (table hard left), the only way the table and workpiece can move, is to the right.
Home = 0.0
MIN_LIMIT = -11.75
MAX_LIMIT = 0.0
HOME_OFFSET = 0.0

Y Axis
The motor and its stop are on the front of the table, so from the stop position (table hard to the front), the only way the table and workpiece can move, is inward, toward the Z pillar.
Home = 0.0
MIN_LIMIT = 0.0
MAX_LIMIT = 5.0
HOME_OFFSET = 0.0

Z Axis
The motor and its stop are at the top of the Z pillar, so from the stop position (headstock hard up), the only way the headstock and tool can move, is downward, toward the table.
Home = 0.0
MIN_LIMIT = -0.0
MAX_LIMIT = 6.0
HOME_OFFSET = 0.0

One oddity, is that for the Z axis to pass a move-out-then-move-back-home test for some given distance, the MIN_LIMIT had to be "-0.0", because "0.0" would fail with a complaint about hitting its soft limit. That got solved, but it's peculiar...

Thx!

- Bob

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6 years 4 months ago #171269 by tommylight
For a mill, the X and Z axis are set wrong, X should always move on the positive side and Z on the negative.
So for X
min limit can be 0
max limit should be positive value of how far can that axis move.
For Z
min limit has to be the bottom of the travel, so -6
max limit should be 0

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