Homing Y issues

[mtlchsr]

Hi.... back again.... I am trying to complete set up of homing on my conversion of Vertigo MX2 to Masso

I have Z and X homing ok and in sequence as set up in F1

However when Y starts - only one side ( one stepper motor) moves. There are two steppers for Y. one at each side of table. I have the slave box ticked (B) to slave to Y in F1

I have an MPG pendant and can move back and forwards with the dial ok and both Y stepper motors move together in either direction.... but only before trying the homing (ctl+alt+home)... see below

I note that after stopping the homing (activate e-stop) and trying to move Y axis with the pendant... it only moves in one direction - both motors work but not in the opposite direction now. Huh! More witchcraft ... or is there something I missed here, I cant see anything about this senario in CNC nutz how to video. Help please.

 

[breezy]

@mtlchsr, @masso-support

If you have a G3 MASSO you need to place dummy data into the A axis if you aren't using it.

Search forum for not working, frozen, etc complaints and you will find most G3 problems are lack of dummy data in unused axis.

I have asked Masso-Support to place a warning on the Home page of the documentation regarding this problem, but it is yet to appear. All new MASSOs being shipped now have dummy data in the axis setup to overcome this problem.

Regards,

Arie.

 

[mtlchsr]

Hi, Thanks again Arie, alas this is not the issue - would have been nice for a quick fix. Not 100 % sure what 'dummy data' is but guessing it just means some figures in the boxes under F1 'A axis'. My A has all lines with some kind of numbers... looks like the default number that came for all axis. S presumably my G3 and software update used cames with the fix. Anyway...

I have done enough trial and error fiddling to come to the conclusion that the B axis motor lacks 1 direction when doing a home sequence (same situation as above) Am suspicious that it may be due to travel distance envelope... I need more time to explore this idea. Also I seem to get wild 'Machine' readings when I de-slave the B axis (as I need to correct the miss match in gantry alignment due to it not moving when slaved and trying to home - it's only a few mm as I hit E-stop asap when I see it is not working correctly) I can have everything saying Zero = 0.000 on all axis, I can move/jog manually around all axis ok with MPG or buttons on F3 screen.

I seem to loose all machine zeros and positioning when I deselect 'slave to Y' option on B. Does the motor think it is out of travel due to being at end of soft limit? Seems like I have to set the B travel in the set up wizard separately ??? Am going to try that and report back. Weird.

 

[cncnutz]

@mtlchsr

When you set up the B axis as a slave it will automatically copy the settings from the y axis and use that. I can't quite figure out what is going wrong with your setup from your description and I haven't come across the issue you have. You mention watching a video and I assume it is the one below but can't be sure because you mention the travel envelope but that was the first thing taken care of in my video so maybe you haven't seen this one.

You can also post your settings file here or screen prints of the home and axis settings which could help figure out the problem.

Double check that the B axis home sensor input is actually the home sensor and not the B axis alarm as people have made this mistake in the past and it causes all sorts of problems with homing.

Cheers Peter

 

[mtlchsr]

Hi Peter, Thanks for reply.... I have closely watched video episode 15 numerous times...and yes that was the video I referred to above.

1) Yes slaving B does copy settings from Y. I have just had yet another check of my physical wiring to see if there is something out of whack that I can spot... but no I can't see it. Also my guess is that if my connections were wrong then why would the MPG and screen buttons work ok?. Must be doing something else wrong.

2) B axis has no sensor..... Is that the issue??? I thought the B was a slave and travel would just stop when the limit switch on the other side was triggered. It does seem to be that it is the homing direction that is not functioning (The Vertigo never needed one on the B to home... but does Masso require one?)

3) Don't understand difference between 'B axis alarm' and 'B axis sensor' in your reply... I have 'hard limits disabled' in general settings.

When I restart Masso I seem to have lost my machine co ordinates... Z reads 66.something, X is at 579. something and y at 267. where did these figures come from - I havn't moved the machine from all at Zero. Will attach screen shot of start screen... wait while I find out how to do that.... be back soon

Thanks

 

[mtlchsr]

OK, that was simple enough. screen shot of start up screen attached

 

[mtlchsr]

Hi Just for reference here are the other screen shots after doing a homing routine.. (which includes an 'E-Stop') to stop the gantry getting too far out of align.

 

[breezy]

Quote from Mtlchsr on February 15, 2020, 1:48 am

2) B axis has no sensor..... Is that the issue??? I thought the B was a slave and travel would just stop when the limit switch on the other side was triggered. It does seem to be that it is the homing direction that is not functioning (The Vertigo never needed one on the B to home... but does Masso require one?)

@mtlchsr

B axis needs a sensor. This is how MASSO "squares" your Y axis. If you don't want a B axis sensor then you have to wire the B axis driver in parallel to the Y axis driver and remove "slaving".

On the homing screen remove the B axis Invert Direction checkbox. You want the B axis motor to turn in the opposite direction to the Y axis motor. Until homing is completed MASSO treats the two axis as independent axis. ie. NOT slaved. So they can't be the same.

When I restart Masso I seem to have lost my machine co ordinates... Z reads 66.something, X is at 579. something and y at 267. where did these figures come from

When MASSO shuts down it doesn't remember the position it is at. So on startup the numbers in both Machine & Work DRO are random and upon homing the Machine Coordinate System DRO sets to zero and the Work Coordinate System DRO sets to the relative position for the values in the WCS table (F4) for G54.

Regards,

Arie.

 

[mtlchsr]

Yes... Thanks again. Peters comments sparked a thought in my fozzy little brain last night and so first thing this morning I wired up another limit switch and assigned an input pin.... quick test run and all looks good.... Great..... simple fix. Wasted 2 days of searching thinking, wondering! Masso needs to mention somewhere for builders/converters that 'slave' axis only means 'part time slave' and you must have individual limits on double motor axis.

Imagine... 'part time slaves'... what would the world come to. I'm going to get that second motor a whippin' , But hey perhaps I should not be so hasty... I mean think of my own 'part time vegetarianism' I should be more forgiving and express solidarity for the troubled, even if it is only a rebel motor... but then again, it is only doing what it was told to do, oh dear life is so full of contradictions and now I'm confussed or is that spellt confuddled ?.....

Thanks also for the comment re start up machine positions... that was my next worry.

I will install the second limit switch onto the B axis... cant wait to see what is the next 'issue' 'going forward'.....

Appreciate the help folks. Mtlchsr

 

[derekmccoy]

I learnt this the hard way too. My slaved axis would not move during homing. Took me 2 days to figure out it was because the slave will not home if it has no sensor assigned to it. What I ended up doing is using the same sensor for both the master and slave by putting a jumper of the inputs. If you have a machine as rigid as mine, it should be fine. Another thing to note is that the homing position is not copied from the master axis to the slave, so it will home fine but then Masso will throw a "door open" alarm (even though there is no door sensor). You have to make sure your homing position for slave axis is the same as your master axis.

 

[safeairone]

Quote from Mtlchsr on February 15, 2020, 8:27 pm

Masso needs to mention somewhere for builders/converters that 'slave' axis only means 'part time slave' and you must have individual limits on double motor axis.

Similar to this one in the documentation? ?:

 

[cncnutz]

There are 2 different types of slaving in Masso.

Hardware slaving where you connect both drives to the same to the Y axis and don't use the B axis at all. You can wire it in such a manner that you have can have the 2 drives running in opposite directions. To reverse the direction of travel in Differential mode simply swap the D+ & D- wires on the drive you want to reverse. If you are using common ground mode then connect one of the drives to D+ and the other to D- and they will move in opposite directions. Alternatively reversing the polarity of one phase of a stepper motor will also reverse it as well so there is no need to use software slaving just to reverse the rotation of one drive.

Software slaving where you use the Y & B axis in slave mode. The point of this mode it to provide auto squaring of the axis. If you don't want auto squaring there is no point using software slaving. This mode is a must with Rack & Pinion or belt drive machines as they can easily be knocked out of square when the power is off. To auto square the axis both the Y & B axis need homing sensors / switches to align both sides before they lock together to become a single Y axis.

Cheers
Peter

 

[haris44-hagmail-com]

I have also faced this same issue but when I check my input configuration. I have configured A axis instead of B axis. After changing this homing sequence work properly

 

[ian-mellin]

hello, I have read this and have a similar issue.

I have my 'Y' and 'B' axis software slaved together. So in effect auto squaring. I followed Peter's video on re squaring 3,4,5 and use a multiplication in my case 200 mm per unit, hence 600 mm 800mm and 1M. when I measure the 1M length I am about 2mm out of square is there a way to adjust the square using the software so that it remembers the correct setting.

I need to move the 'B' axis about a 2mm to correct the 1M measurement.

Both my 'Y' and 'B' axis have homing sensors on them, so homing works correctly.
The machine is belt driven with 1:10 gearboxes on the X and Y & B axis.

I hope these is something i have overlooked that can fix the misalignment.
I though about backlash but not sure this would correct the issue as the belts are taught.

Kind Regards
Ian.

 

[cncnutz]

Hi Ian,

You just need to move B axis sensor by 2mm to square the axis.
In theory you could change the Y or the B axis pull off distance but this means that you are purposely forcing the Axis out of square whenever you home the machine and then move it back into square. This is not good for the machine and will stretch belts and twist the axis unnecessarily. Moving one of the sensors is the correct way to fix the issue.

Backlash will not fix a misaligned axis.


Cheers Peter