Kit's Machine

The AXBB-E is on it's way, I have a licence code for UCCNC and have been reading the manuals. I'm currently using 12V for the proximity sensors for the simple reason that I'm using a standard PC power supply (5V and 12V with plenty of current available) for the controller.

24V is obviously better to help avoid interference but the AXBB-E manual doesn't give a current rating for that supply, possibly because it depends on the external equipment connected. What rating of 24V supply do other people use on these cards? I'm using the standard eBay proximity sensors and Huan Yang VFD with nothing else unusual included. I've been looking at small 2A units as there isn't a lot of spare room in the box. I'll still need the PC PSU in there for the 5V supply and 12V for the cooling fans and dust extractor relay.

Kit

The 24 Supply will tolerate 12-24V. All that supply is used for is the bias to the optocouplers on the isolated inputs, and the feed to the high-side of the (low-side) switched (MOSFET) outputs. The actual voltage is largely irrelevant (you'll get less current through the LEDs on the isolated inputs.... but they'll switch reliably). My personal view, and I'm ready to be corrected, with the isolated inputs that there's enough immunity introduced to not warrant a separate 24V supply and given space constraints and pre-existing 12V supply - I'd use the 12V supply. You know how the wobbly-wobblies work, Kitwn, let you come to your own conclusion.

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Originally Posted by Doddy

The 24 Supply will tolerate 12-24V. All that supply is used for is the bias to the optocouplers on the isolated inputs, and the feed to the high-side of the (low-side) switched (MOSFET) outputs. The actual voltage is largely irrelevant (you'll get less current through the LEDs on the isolated inputs.... but they'll switch reliably). My personal view, and I'm ready to be corrected, with the isolated inputs that there's enough immunity introduced to not warrant a separate 24V supply and given space constraints and pre-existing 12V supply - I'd use the 12V supply. You know how the wobbly-wobblies work, Kitwn, let you come to your own conclusion.

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Thanks for the info Doddy.

I was having the wobbly-wobblies about spending all this cash on a new controller and having all the same problems again! As I now live within a five minute drive and an overnight ferry's journey of where all the Australian stock of eBay products is kept I might test it all with the existing 12V supply and only order a 24v unit if there are any problems. I must get out of the mindset that everything takes 2 weeks to arrive by post from within the same country and so pre-emptive purchases are required for getting anything done.

Kit

It's arrived!
Funny that it takes DHL 7 days to get the little beastie from one side of the planet to the other and another 7 days to get it from one side of the Bass Strait to the other, but they said delivery would be on April 12th right from day one and it was.

Setup went according to the instructions, my laptop obviously has automatic configuration for the straight/crossover cable issue as I'm using a straight cable for direct communication. It took two attempts at opening CCNC with the licence file installed to get UCCNC to start up not in demo mode and to get the laptop and card talking to each other but all seems fine now.
Tomorrow I will look at configuration of ports, limit switches etc. and how to get auto-squaring on the two-motor X axis working. Once that's all done and looking good I can rip the old parallel card out of the machine controller and fit the shiny new one in it's place. Then I can see what postprocessor to use in CamBam and what improvement in performance the more accurately timed pulse streams from the AXBB-E compared to LinuxCNC will give me. What chance 23m/min rapids instead of the current 9?

Kit

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Originally Posted by Kitwn

Tomorrow I will look at configuration of ports, limit switches etc. and how to get auto-squaring on the two-motor X axis working.

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It doesn't have auto squaring, each motor moves independently while homing and you just adjust the home switches to square the gantry.

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Originally Posted by JAZZCNC

It doesn't have auto squaring, each motor moves independently while homing and you just adjust the home switches to square the gantry.

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Pooh! I thought somewhere I'd read that auto-squaring was possible. Perhaps it was in a possible-future-devoplments chat on the CNCDrive blog or similar.

Back when I had microswitches placed where they could get smashed if they failed to operate and the old version 1 of LinuxCNC on my machine I made a micro-adjustable end-stop (OK, it was an M6 bolt in a bit of aluminium angle) for gantry squaring. That dissapeared when I upgraded to proximity sensors. I'll need to to come up with something similarly cunning for the new installation. The present arrangement is far too clunky for easy fine adjustment which is currently tuned to a hair's breadth in the LinuxCNC v2.8 config file. Once it's been made, a properly implemented mechanical adjuster will be quicker to set up anyway.

Kit

I've spent part of this afternoon reading through the manuals for the software and hardware and configuring the AXBB-E on the desk before I start installing it. There seems to be a lot more to configure than there was with LinuxCNC but I suspect this is due to the greater versatility of the AXBB-E over the simple parallel BoB that LCNC uses.

One thing I am still puzled about is the 'units'. Lots of elements in the setup refer to being in 'Units' without specifying them. I'm asuming the default is mm rather than inches but there doesn't seem to be anywhere to specify what units you want to work in. It can't just be looking for a G20 or G21 in each job's file and working from that can it?

Kit

From memory, it’s unit-less and ignores G20/21.

Configure for metric or imperial and stick with it. Or have an imperial and metric configuration file

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Originally Posted by Doddy

From memory, it’s unit-less and ignores G20/21.

Configure for metric or imperial and stick with it. Or have an imperial and metric configuration file

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I haven't fully got my head around how you can be 'unitless'. Is the idea that once I've input the number of steps required to move one of my chosen unit (mm, micron, yard, cubit) the software simply treats that many steps as one 'unit'?

Kit

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Originally Posted by Kitwn

I haven't fully got my head around how you can be 'unitless'. Is the idea that once I've input the number of steps required to move one of my chosen unit (mm, micron, yard, cubit) the software simply treats that many steps as one 'unit'?

Kit

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That's exactly my intended meaning. Whether my meaning is right or wrong... but I think it's right. I normally get a "ignore-me pester box" whenever I import g-code from Fusion that typically complains about the first G20/G21 as an unsupported command.

Aha, if you'll support a remote link... http://cncdrive.com/forum/viewtopic.php?f=4&t=769