Andy's description of the Mach external pulser API is correct. The device driver gets to select the length of the buffer and also select a "pulses per time slice" or a way-point version of the data.
USB under Windows seems to require at least 1 second of buffered data to be workable. Not pleasant, but lots of people use it anyway. USB itself is not the problem, it is the Windows protocol stack that can cause significant delays. It is optimized for throughput not minimum latency. E-Stop, limits, homing, probing, and threading are the responsibility of the device and its driver. This results in lots of complicated code in the driver and significant variations in performance from one type of device to another. Steve Stallings > -----Original Message----- > From: andy pugh [mailto:bodge...@gmail.com] > Sent: Friday, February 28, 2014 8:52 AM > To: Enhanced Machine Controller (EMC) > Subject: Re: [Emc-users] Printrboard and LinuxCNC > > On 28 February 2014 13:36, Michael Haberler > <mai...@mah.priv.at> wrote: > > >> The question, then, is how come Mach3 can have USB > cabling, but LinuxCNC > >> can't? (see the KX* mills from Arc Eurotrade in the UK; > now with USB input) > > > > I have no idea about that API uses over USB, but I'd be curious > > There is a clue on page 26 here: > http://www.warp9td.com/documentation/SmoothStepperUserManualV1.0.pdf > > It looks like the SmoothStepper accepts 1kHz position data, rather > similarly to the Mesa and Pico boards. The difference seems to be a > buffer of around 1 second. > I assume that e-stop (at least) is handled on-board. I rather assume > that limit switches and homing need to be too. > > -- > atp > If you can't fix it, you don't own it. > http://www.ifixit.com/Manifesto > > -------------------------------------------------------------- > ---------------- > Flow-based real-time traffic analytics software. Cisco certified tool. > Monitor traffic, SLAs, QoS, Medianet, WAAS etc. with NetFlow Analyzer > Customize your own dashboards, set traffic alerts and > generate reports. > Network behavioral analysis & security monitoring. All-in-one tool. > http://pubads.g.doubleclick.net/gampad/clk?id=126839071&iu=/41 40/ostg.clktrk > _______________________________________________ > Emc-users mailing list > Emc-users@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/emc-users > ------------------------------------------------------------------------------ Flow-based real-time traffic analytics software. Cisco certified tool. Monitor traffic, SLAs, QoS, Medianet, WAAS etc. with NetFlow Analyzer Customize your own dashboards, set traffic alerts and generate reports. Network behavioral analysis & security monitoring. All-in-one tool. http://pubads.g.doubleclick.net/gampad/clk?id=126839071&iu=/4140/ostg.clktrk _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
