On Sun, 2 Dec 2018 at 02:13, Thaddeus Waldner <[email protected]> wrote:
> > Now what I really want to know is, in the case of multiple DC power > supplies, is it advisable to connect the negative terminals of each, and > are there any pitfalls in doing that? For example, can I connect the > negative terminals of the 5vDC supply and the 24vDC supply to the 7i96 > isolated input common terminal? I believe I incorrectly called the negative > terminal the ground earlier. > I think it is better, in principle, to keep the logic and power DC supplies separated, though you need to keep careful track of how they interface where they meet. If it is at opto-isolators then the two supplies can be referenced entirely separately. However, in practice, there is nearly always some component in the system that ties them together, a drive or break-out board or something. And in that case you probably want to do it explicitly rather than have an unknown connection in an unknown place potentially passing quite high currents. Now, is there a “home command” signal that I can connect to the enable > signals of my ClearPath motors in order to sequence the homing routine? I think you would need to configure LinuxCNC for immediate homing (HOME_SEARCH_VELOCITY = 0) and have the servo drives control the homing HAL pin. This is the reverse of how you are probably imagining it. Rather than LinuxCNC telling the motors to home, the servo drive (and some HAL logic) needs to tell LinuxCNC "this axis is now at home" Do the servos output any signal to say that they have completed homing? It's slightly annoying that the HAL pin to home an axis is in the (userspace layer) halui component, but this is because homing is triggered by a queued command. http://linuxcnc.org/docs/2.7/html/man/man1/halui.1.html Home-switches and home-to-index should be just as good as the hard-stop homing. But probably no easier to configure. -- atp "A motorcycle is a bicycle with a pandemonium attachment and is designed for the especial use of mechanical geniuses, daredevils and lunatics." — George Fitch, Atlanta Constitution Newspaper, 1916 _______________________________________________ Emc-users mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/emc-users
