dual y axis not in sync #SOLVED#

aidenwolf
Posts: 34
Joined: Mon Sep 21, 2015 1:44 pm

Re: dual y axis not in sync

Post by aidenwolf » Tue Sep 29, 2015 6:46 am

DRobs86 wrote:For the record people need to be careful adjusting those polulu drivers. Luckily I have not done it but I've heard of a lot of people destroying them by shorting them.

Also... Not sure if you ended up sending this to cov but you may want to check your fuse on the protoneer shield. They are often cheap Chinese clones. Mine was and the fuse from motor supply to ground blew dang near immediately. I checked for problems extensively and just ended up putting a reasonably guaged jumper across the fuse and have since cut dozens and dozens of pieces with no problems.

And the winner is...... DRobs86! I wired across the fuse on the CNC shield as you suggested. Initially I was worried because there was a minor explosion on the board when I plugged the power in, but lo and behold the steppers could be moved!
I then set the href voltages on the drivers as the Pololu website says. I found this incredibly difficult to get accurate. I was after 0.75V for each one, but ended up with a range of between 0.73V-0.78V for all 4 drivers. Anyway it all appeared to be running smoothly so I tried the 'Hello World' exercise again. Previously the S and H would draw correctly then it would mess up the rest of the letters, but after setting the correct voltages the whole thing worked first time!

I'll try cutting something tonight for the first time and see how that goes. I've also ordered a new CNC shield and drivers - just in case.

Thanks for all your help guys. I'll write up an instructable for how I see how to get the electronics running first time on these machines.

DRobs86
Posts: 148
Joined: Fri Jun 05, 2015 4:19 am

Re: dual y axis not in sync #SOLVED#

Post by DRobs86 » Tue Sep 29, 2015 4:50 pm

Glad it is working for you. That audible pop concerns me. My first instinct is that the fuse just blew then (was it blown before you jumped it), but there should be less current not more running through an intact fuse when it gets jumped.

Either way I'm happy it is running for you. Just keep an eye on it for a while because little electronics can start big fires. Again though, I jumped mine bc it was blown and all is well.

On the vref.... The best way to do this is to aligator clip a small screwdriver to your positive probe and then turn the potentiometer with the screwdriver as you watch the voltage reading.

Also, what amperage rating do your motors have? If they are 1.5 amp motors you probably want to back down to .7V or lower on that reading.

aidenwolf
Posts: 34
Joined: Mon Sep 21, 2015 1:44 pm

Re: dual y axis not in sync #SOLVED#

Post by aidenwolf » Fri Oct 02, 2015 11:46 am

Yep all working fine - I have got spare drivers and CNC shield though in case anything breaks now.
See pictures below of Hello World success.
I tried some milling too, worked great to a 4mm depth. My end mill is only 2mm diamter 12mm cutting depth, so I've ordered some beefier end mills to do the stuff I really want to do.
I used Delcam Featurecam to generate the NC code, worked very well and dead easy to use software.
I've been using Delcam products (but not featurecam) for years though and highly recommend their stuff.


Image

DRobs86
Posts: 148
Joined: Fri Jun 05, 2015 4:19 am

Re: dual y axis not in sync #SOLVED#

Post by DRobs86 » Sat Oct 03, 2015 4:58 pm

Well done. That machine is a good size. It was hard to tell on my phone looking at that pic.... But your Y does have midspan supports right?

Congrats on the good results.

Post Reply