Modified M74 to restore soft limits if homing interrupted

[RHarris19]

****Updated M74 file in my follow up post to keep 150 available for ATC operation****

We have been working on modifying M74 to move the old limits to non-volatile values 152-159 so that if the homing is interrupted, it won't lose the soft limit values. The Master Axis was moved to 150 and Slave Axis to 151 to keep it clean. M75 was also updated to reflect that change as well.

This has come up a few times in getting one of our machines setup and seems like it could help others.

Let me know if anyone can see an issue that may need to be addressed.

[landmark573]

I have had this issue several times on my plasma table. I’ve also noticed that if the homing cycle is aborted because the master axis hits the home switch before the slave axis the soft limits are lost. I didn’t notice this at first because I thought they were only lost if I did something to interrupt the homing cycle like hitting the e-stop. I will try out your changes.

[RHarris19]

Make sure that you use the updated M75 as well to have 151 assigned correctly in both.

Originally, I just updated the code to have the macro restore the saved values before ending if the master tripped before the slave, but thought it would be good to go a step further in case anything else interrupts the homing.

Let me know if any issues come up.

[RHarris19]

One thing that came up as a potential problem with this was that, with a tool changer, #150 is normally used to remember the tool that was in the spindle. My setup has Axis 4 software paired with Axis 1, so I was able to still utilize #154-159 for the limits of Axis 1-3, with Axis 4 +/- limit going into #148/149, which are volatile variables. I believe that ultimately shouldn't matter, Axis 4 will utilize the software limits of Axis 1.

I have modified the M74 file again with that taken into consideration. The original M75 file, with the Master at #151 and Slave at #152 should be used.