Hi, You should not make a loop of wire for the ground (gnd from switch to switch to switch is not good). You should have one wire for the switch input, and one wire for the signal ground in your switch cabling. All of the grounds from the various switches should meet at one point on the I/O terminal signal ground point. If possible, you should use shielded cabling. Tie all of the shields (bare drain wires) at the same end near the inputs, but then connect them to an *earth* ground, not the signal ground of the input. An example of an earth ground in a system would be the green wire (or green with yellow stripe) of a power supply, not the V- of the power supply. 2-wire 22 gauge "sound and security" from Home Depot, etc. will typically be stranded wire with a drain wire and shielding. This would be a good choice as it has all three of the conductors that you want. Red for signal, black for signal ground and bare drain for shielding.
Jeff On Friday, July 24, 2020 at 10:40:34 AM UTC-7, Frederic RIBLE wrote: > > Could you describe the wiring of these switches on your machine? > I am wondering if you have two wires per switch going up to the logic > board, or only one, with ground sharing. > On 2020-07-21 19:39, Mason Millner wrote: > > We are using momentary hinge limit switches ( > https://www.amazon.com/URBESTAC-Momentary-Hinge-Roller-Switches/dp/B00MFRMFS6/ref=sr_1_3?ie=UTF8&qid=1535482225&sr=8-3&keywords=limit+switch) > > and our spindle ( > https://www.amazon.com/Koolertron-Spindle-Milling-Converter-Engraving/dp/B074XTKJTJ/ref=sr_1_9?ie=UTF8&qid=1535482152&sr=8-9&keywords=spindle+cnc) > > is operating from its own power supply. > The machine is fairly rigid. No limit switches are triggered from until > material is being cut. The bamboo does vibrate quite a bit as it spans 65" > supported only on the ends, but we have been able to successfully cut this > dimension previously (on a 3-axis Techno machine). > > > On Tuesday, July 21, 2020 at 1:12:01 PM UTC-4 blaz...@gmail.com wrote: > >> You didnt mention what type of limit switches you're using or how your >> spindle works. The Y axis itself shouldn't be under any special stress >> while cutting but the spindle generally takes a hard hit as soon as a tool >> enters the cut. Is the spindle motor powered by the same power supply your >> switches are on? Supply could be dropping low. Is the machine not ridgid >> and vibration tripping the switches? >> >> On Tue, Jul 21, 2020, 8:54 AM Mason Millner <mmil...@vt.edu> wrote: >> >>> Hi All, >>> >>> We are developing a 4-axis CNC to mill bamboo poles and are currently >>> running tests in just three axis (x, y, z). We can dry-run g-code files >>> successfully, however we receive limit switch errors (primarily on joint 1) >>> when we begin cutting material. We suspect that the error is occuring in >>> the y-axis and that possibly our drivers are causing a problem (either they >>> are too small or not tuned adequately).. It is difficult to tell what is >>> going on and how the machine is configured from the information given. >>> >>> We have the z-axis running on the long x-axis, running on two shorter >>> dual y-axes. >>> >>> The axis shaft is a ½” (12.7mm) , also the motor shaft is ¼” (6.35mm). >>> we are using polyurethane insert couplers (these have regularly been coming >>> loose though). >>> >>> The motors are NEMA 23s with 3A rating/phase controlled by Pololu >>> TB67S249FTG drivers on a Cramps 2.2 cape on the Beaglebone Black. The >>> drivers have a current limit of 1.6A and are further limited to %90 for >>> safety. The Current limit for the board and drivers are defiantly a bottle >>> neck, but the motors have enough power to operate. [Could this be the >>> problem?] >>> >>> Any help or recommendations would be greatly appreciated. If more >>> information is needed please let me know. I'm fairly new to the machine >>> development side of this project. Thanks. >>> >> -- >>> 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+...@googlegroups.com. >>> To view this discussion on the web visit >>> https://groups.google.com/d/msgid/machinekit/790379d8-160b-4fed-9fa2-d03cbe160926n%40googlegroups.com >>> >>> <https://groups.google.com/d/msgid/machinekit/790379d8-160b-4fed-9fa2-d03cbe160926n%40googlegroups.com?utm_medium=email&utm_source=footer> >>> . >>> >> -- > 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 machi...@googlegroups.com <javascript:>. > To view this discussion on the web visit > https://groups.google.com/d/msgid/machinekit/8c6cb16c-03d6-4c1c-8cc5-0d8ad5012849n%40googlegroups.com > > <https://groups.google.com/d/msgid/machinekit/8c6cb16c-03d6-4c1c-8cc5-0d8ad5012849n%40googlegroups.com?utm_medium=email&utm_source=footer> > . > > -- 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. To view this discussion on the web visit https://groups.google.com/d/msgid/machinekit/9aa5e3a1-88e6-4a97-a09c-2d2b8f4f7a21o%40googlegroups.com.
