Homing brain fog?

Hi all,
Finally got around to LinuxCNC'ing my cheap bench top mini mill, making the jump from Arduino/GRBL (Ughh) to a Mesa7196S.
Problem is my Y axis is making me feel like my IQ has plummeted..

X and Z, perfect (have opto sensors at Z+ and X- (X is mounted to the left of Y saddle as viewed from front - aiming to have bottom left corner as my 0,0).

Unfortunately I appear to lack the logic to get the Y limit configured so that it can be a combined home/limit at +145mm without mirroring the Y axis!
For clarity: I want to home the machine by moving the bed fully to the right for the X axis (working) and fully towards the idiot Operator (tool max +Y), but everything I have tried either inverts the Y or results in soft limit exceeded.

My ini and hal are attached, any help will be very much appreciated!

Cheers,
Rog

I had the same problem with my Z-axis.

I fixed mine by recreating a new config with stepconf and using the default values as guidance.

Remember that a travel of -140 <–> 0 ≠ 0 <–> 140.

It's weird sometimes.

I remember that "What the....." feeling.

(bewilderment is the word)

(140 is just an example)

Be aware that while LEDs should last forever, their brightness diminishes with age.

Eventually, the sensors won't detect homing.

I would recommend physical switches, but whatever.

You don't need a combined home/limit.

The home switch is also a soft limit.

(don't run the machine unless it is homed of course, that would remove the soft limit, which would be bad)

IIRC (It's been a while), home is always 0.

Run PNCconf and create a new config and see what the default is.

Worked for me.

Is there some reason the home sensors can't be at 0?

Try stuff out 'till it works (or you start to feel tired)!

Glad I'm not the only one loosing 100 IQ points when setting up homing......your description is perfect lol.


If your homing switch is by the operator
Set y max to zero
Set y min to -145
Leave default homing.
Set your 0,0 in g54 after startup.

The above sets 0,0 to the upper left. Getting it to the lower left isn't possible without flipping an axis (right hand rule problems).....hence the g54 zero after boot up.


If your homing switch is away from the operator....this one gets rough.
Same idea as above
Y max is now 145
Ymin is zero
All homing is inverted. (Direction, latch, etc)
Then set the y offset to -145 and it should home then drive back to the operator

This is from memory so it might be wrong....but that's the general idea. I make sure my axis is moving in the correct direction, if it's not I flip it electrically, not in software, to make this easier.

Thanks all for the insightful inputs!

I did as suggested, scrapped old config and created a new one using Mesa CT with the suggested home settings.
All golden now! (I had been going around in circles before...).

Opto switches - I had not considered the scenario where the LED had deteriorated, considering now putting some good old fashioned limit switches in, and using the opto for homing only (they have great repeatability).

Now to make some chips - I have 3D printed prototype hardware for the ball screw mounts (using ASA with 100% infill), now to see if I can coax them to at least center drill the parts in aluminum, after squaring up with Z physically locked and taking very cautious lateral cuts.

My experience exactly!

Default values are often default for a reason.

BTW, LEDs take forever get dimmer.

Like they should at least 15 years b/c you don't have them on 24/7.