Mar 27 2017
05:22 PM pcw_mesa: Has the UVW blend stuff been merged to master?
05:39 PM andypugh: Met up with Rene Hopf yesterday, came away with an STMBL
05:40 PM andypugh: It’s a very LinuxCNC servo drive. It works as a smart-serial device, you plug it in, it appears as a set og HAL pins.
05:41 PM cradek: wow
05:43 PM andypugh: If you plug in to it with a USB cable and run a Google Chrome App (OK, that part vaguely scares me) you get a live graph and a very familiar-looking HAL interface. The commands are a bit different, but it is very much like LinuxCNC HAL, with two fast threads and a userspace thread.
05:45 PM andypugh: And, whilst I can’t quite recall all the pin names, something like vb.position = sim.sine // sim.gain = 10 will set the motor oscillating through 10pi radians, and plot.wave1=vp.position will plot the position.
05:48 PM andypugh: I need to set it all up here, and learn it, but it’s a pretty neat drive. And runs 320V and 1kW
05:49 PM andypugh: This is all it takes to hook it up to HAL. https://github.com/rene-dev/stmbl/wiki/Linuxcnc
05:50 PM andypugh: lin2rev is a HAL component that converts engineering units to radians.
06:07 PM skunkworks: cool
06:09 PM andypugh: I need to do a lot more experimenting with it, and it isn’t currently something you can actually buy, but I am becoming convinced
06:43 PM skunkworks: do you have to tune it at the drive? or does it act like a dumb amp?
06:44 PM skunkworks: (linuxcnc closing the loop)
07:16 PM andypugh: Sorry, I wandered away.
07:18 PM andypugh: The STMBL is a very smart drive, almost the opposite of the 8i20 for example. It expects to get the encoder feedback, for example, and just reports the position back to LinuxCNC HAL.
07:19 PM andypugh: There is a tuning process where you can have the drive move the motor and work out many of the important parameters.
07:20 PM andypugh: There is a lot to be said for a drive that can measure back-emf and current at 5kHz. Also, it supports an impressive, and gromwing, set of encoder formats.
07:20 PM andypugh: (growing)
07:23 PM andypugh: I am new to it. I think that you could configure it as a dumb drive if you wanted. As I mentioned, it has its own HAL layer and you can load, or not, whatever modules you need.
07:26 PM andypugh: Anyway, I need to get a keyboard for the test PC I am using, to experiment further :-) Bizarrely I don’t appear to have a generic USB keyboard any more.
11:13 PM Tom_itx is now known as Tom_L