Re: [Machinekit] Advice for BBB breakout for Taig Micromill

[schoone...@btinternet.com]

On 18/04/17 23:26, Siggi wrote: Hey y'all, I recently had a 4 axis Taig Micromill DSLS 3000 follow me home. I'm currently driving it with Mach3 and a ThinkPad laptop, through the USB->Parallel port module provided by Taig/Microproto, but this is ... sub-optimal. The driver box takes what looks to me (a rank n00b) standard DB25 parallel signals for XYZA step/dir control and spindle/coolant switching. The DLSL allegedly has 1600 CPR encoders that hook into the control box and are supposed to "servo" the steppers. From what I read the stepper drivers are half step only, however, so I don't know. The only user-visible benefit to this that I've seen is that if (when - *sigh*) I crash, the encoders detect it and flag on the respective axis "limit" inputs on the DB25. Sometimes it seems the USB module takes ... a while ... to bring this to Mach3's attention, however. I guess it may also help to have an acceleration/speed control loop around the steppers? USB does not work, there is no certainty as to poll interval, there are repeated in depth explanations of this on the Linuxcnc forum if you are interested In any case, I want to kit my mill out with homing switches at least, and perhaps limit switches. There are suitable inputs on the control box, but they get ORed with the servo loop "limit" gunk, which means the control software wouldn't be able to tell home from "limit". I'd also like to liberate the ThinkPad from machine control duty. In any case, I'd like to hook up a BBB with Machinekit to the control box I have already, and to hook up the home and perhaps limit switches to it. Ideally I'd want a breakout with a DB25 feeding the XYZA axis and the the spindle/coolant outputs, as well as the XYZA limit inputs. Screw terminals would be ideal for the rest. I wonder which cape or breakout board would be best/reasonable for me to buy for this (I'm in Canada, in case that makes any difference)? Why do you want to use a BBB? All you need is a small form factor ex corporate x86 desktop with a parport, available for £30 on ebay. You can run the whole machine from one parport, if you chain the limits to one pin (which limit tripped will be obvious from the table position, so you don't need to waste 3 pins on them) Or fit a £10 PCI parport card and have loads of extra IO. You will need to run Linuxcnc with a rtai kernel probably, to get decent latency, but lots of people there are already using Taig mills quite happily, so you will have lots of advice available. Alternately the DE0-NANO-Soc is about £80 and with a DB25 header board you can have 4 hardware stepgens, hardware encoder and 16 pins of GPIO, running Machinekit. I have a small mill (albeit about 10x the size of a Taig) running very happily just using one header for steppers etc. and the other for IO. The downside with BBB or DE0-NANO is you still require another computer to access the board and provide graphics. So any 'space saving' is often notional. I am not evangelical about Machinekit, it is a case of whatever works best. Machinekit is nothing to do with BBB, despite the impression the number of people using them gives. Siggi -- website: http://www.machinekit.io blog: http://blog.machinekit.io github: https://github.com/machinekit --- You received this message because you are subscribed to the Google Groups "Machinekit" group. To unsubscribe from this group and stop receiving emails from it, send an email to machinekit+unsubscr...@googlegroups.com. Visit this group at https://groups.google.com/group/machinekit. For more options, visit https://groups.google.com/d/optout. -- website: http://www.machinekit.io blog: http://blog.machinekit.io github: https://github.com/machinekit --- You received this message because you are subscribed to the Google Groups "Machinekit" group. To unsubscribe from this group and stop receiving emails from it, send an email to machinekit+unsubscr...@googlegroups.com. Visit this group at https://groups.google.com/group/machinekit. For more options, visit https://groups.google.com/d/optout.