ATC Project - Debug phase

tommylight wrote:

Just a stab in the dark, but maybe those are somehow/somewhere/no idea/ tied to some divisions from one pocket to another, so when the requested value can not be divided it does extra rounds till it gets to what can be divided.
 

Good idea.

I changed the stepper drive steps/rev and recalculated the carousel.0.scale... still acts the same.  I've got the drive steps/rev set so that carousel has an even number of steps per pocket.  Used to be 1000 counts per pocket, now it's 1250.  No difference.

I did notice that at the slightly higher counts/pocket setting it didn't act up every time when the speed was set to 35.  Once I set it to 50, it failed reliably.

Made a horrible little video demonstrating the issue.

Horrible video - carousel.comp "counts" error

Maybe that can shed some light on what's going on.

I have two sensors installed, but the pocket sensor is not connected in hal any more - only the index.

If you recall, the reason I/we stopped using the pocket sensors is that the actual stopping point is dependent on the motor speed & decel; there's no mechanical device to align a pocket with the spindle and any speed/decel variation (tool weight, inertia) can result in misalignment.

I can install different flags - sheet metal would give a more repeatable (or defined) edge and a longer pulse width.  But even at higher speeds I've  never seen it miss a trigger with the existing pins; they're very close to the proxys.

'Width' is set to 0 - this sounds like it may be the problem.  Here's the comp file description (which you wrote, of course):

pin in signed width = 0 "How far each side of the exact scale to signal a new pocket";

So I left it at the default.

Should the width value be in stepper pulses?  Is this a tolerance setting, so that if I set:

scale = 1250
width = 10

that would be the same as next pocket = 1250 +/- 10 pulses?  Is this going to develop a cumulative error over multiple pockets?

Regarding the slower latch move, I think a homing search with slow back-off (a-la axis homing) would be very useful - the homing sequence is currently dependent on motor speed and decel value much like the issue with using pocket sensors and no mechanical alignment device (Geneva, ratchet).

Assuming the user settles on a final speed, the current scheme still makes the initial setup & pocket alignment tricky while developing a safe (but not agonizingly slow) rotational speed.
 

OMG - progress.

I set width to 5 and it's stable up to speed = 150.  Also had to set the stepgen maxaccel = 0 & maxvel = 0; with those at 'soft' settings it would coast past a pocket (or 3) regardless of whether carousel was getting the counts right.

Since I cant really figure out what the speed units are, I used the stepper tuning software to monitor the RPM via rs232.

150 units  = ~100 motor RPM, 20 carousel RPM (5:1 gearbox).  So with a 4500ppr step count that's a pulse rate of about 7.5khz.

It was actually stable up to 200 units, which was proper fast.  Like Robodrill tool changes.

Thanks a ton Andy.

Now that hurdle is behind me, I'm happy to do more testing if you want to fiddle with the homing or pin sense functions.

PS - while I'm asking for favors, an additional nice-to-have would be the ability to unhome the carousel without having to shut down LCNC and restart it.

That would meat it's it degrees/second since I've got the stepgen scale set to 50.  Or at least it was until I changed the microstepping in the drive to see if different values would change the rotational issue sorted out yesterday.  This passes the sanity test since 150 degrees per second looks about like 20rpm to the untrained eye.

Next moves:

• Remove unused pocket pins & make a better index flag
• Remap M6
• Test sequencing and actually change a tool
• Connect various other remaps to Probe Basic GUI buttons
• ????
• Profit

andypugh wrote:

spumco wrote:

• Remove unused pocket pins & make a better index flag
  
  
  
  Hold off on that. I think that adding a latching move can make the work well. In principle I like the pins.

Holding, Aye.

Easy enough to reconnect sense-01 back in hal; nothing was actually removed from the machine.