I'm very happy with my Lagunmatic 250 milling machine with AllInOneDC retrofit. I recently eliminated my phase generator and replaced the reversing contactors with VFD's. Everything is working nicely on 240V single phase and I have been making money.
I have one leftover issue. Once in a while I will power the mill off when the z-axis is at the Z+ limit (where it has to be to use the air operated drawbar). When I power back up, I cannot home the mill. I cannot jog either. I have to remove the cover from the z drive, manually move Z off the z+ limit, and then I can home. I don't like getting my fingers into the belt drive
I'm sure there are many things I can do, but I would appreciate any advice.
p.s. I made some changes to the source code to run the VFD's. Also, I have two lube pumps; one for the ways, the other for the screws (different oil). The NO alarms were connected in parallel, but I will change them over to NC and provide both inputs to the PLC to have separate 'low oil' messages.
More than 5 years later and this issue happened again. I cannot jog either the Z axis or the X axis. The Y axis works just fine. I powered off and back on but I still cannot home the milling machine, or jog X or Z (with panel, virtual panel, jog controller).
This time I knew exactly what happened. I was manually facing and I ran the X-axis to it's limit - which was part of the plan since the part was at the maximum travel of my X-axis - and then I manually retracted the Z-axis for a tool change. The Z-axis went to the limit which then 'bricked' my mill. I suppose that jogging does not work if there are two axis' at their limits.
The last time this happened, I removed the covers and manually rotated the Z-axis down, and everything was fine after that. This time I'll try to force a limit switch in software and see if I move the other axis off it's limit switch.
Lagunmatic 250
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In Centroid's CNC7 and CNC10 software (1992 - 2010), tripping a limit switch on one axis did not prevent jogging any other axis. Therefore, even if multiple axes were on limit switches, you could jog each one away from its switch (in Slow, Continuous mode).
In CNC11 and CNC12 (2010 - present), tripping a limit switch on one axis prevents any other axis from jogging. Therefore, if two or more axes are on limit switches, you are prohibited from jogging any axis, and you cannot jog the offending axes away from their switches.
I have been arguing for years to get CNC11/CNC12 changed back, to use the CNC7/CNC10 behavior instead. No luck so far.
So, if you have multiple limits tripped, you either have to fiddle with software input inversion or forcing (as you propose above), or you have to manually turn the screws.
On a related note, though: it sounds like you would not have this particular problem if you set up your limit switches and software limits per normal practice. You should never be tripping a limit switch during normal operation, after the machine has been homed.
Once the machine has finished homing (per your cncm.hom file, which has the usual M91, M92 and M26 commands for all three axes), all three axes will be positioned at the first encoder index pulse after clearing the limit switch, and none of the switches will be tripped.
You need to set the software travel limits to allow (only) X+, Y-, and Z- movement from home. Software travel limits are in the last two columns of the Machine Configuration -> Jog Parameters table.
If you are unable to engage the power drawbar with the Z axis at its homed position, then you need to move the Z+ limit switch up -- and possibly re-clock the motor/belt -- so that the drawbar does engage at Z home. You should not have to go above Z home and trip the Z+ limit switch in order to use the drawbar.
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