Just saw your message. If you keep the VFD powered off, do you still have noise issues ??
Dave On 1/4/2016 5:19 PM, John Thornton wrote: > I have 3 DC power supplies in the drive side, a 5vdc, a 24vdc, and a > 170vdc. > > The 5vdc power supply on the 0v side reads 37.6 ohms with the 0v and 5v > sides connected to the 7i77 5v plug. The 7i77 is the only thing it > powers up. When I unplug the 7i77 0v reads open so there is a path > through the 7i77 5v to ground. > > The 24vdc power supply is for the limit switches and push buttons. It > reads open from 0v to ground. > > The 170vdc power supply is a bridge rectifier with a large blue cap and > a power resistor. See the photo in the link of the current panel. I > can't tell which side should be 0v but both sides measure 0.65M ohms to > ground. I don't know if that is reading back through the bridge > rectifier or the drives. It only powers the three axis drives. > > Current panel layout http://gnipsel.com/images/bp-knee-mill/bpel06.jpg > > JT > > On 1/4/2016 10:48 AM, Bertho Stultiens wrote: >> On 01/04/2016 05:34 PM, John Thornton wrote: >>> Well I grounded X2 to the main ground and when I started LinuxCNC and >>> started to home I got the flurry of sserial errors. So I thought about >>> it for a bit and maybe the ground from the computer case to the ground >>> block was creating a ground loop so I took it off. Started LinuxCNC and >>> immediately go a flurry of sserial errors which locks up LinuxCNC. Mind >>> you this is with the 7i77ISOL card between the 5i25 and the 7i77 which >>> is supposed to block any noise in the sserial communications. The X2 to >>> ground has to go... >>> >>> I do have a 7i92 to test out... >> My guess is that you have more than one (ground-)loop. You also need to >> check how the 0V (DC) line interacts with other devices/converters etc. >> wrt. ground and see whether any of them also hook-up to ground somewhere >> along the wiring, PCBs or supplies. >> >> The second type of loops can be (entirely) in the 0V (DC) connection(s) >> where multiple paths, with different impedances, impair the integrity of >> the signal lines. You need to check how the different DC supplies >> interact with the connections as they are. The problem often becomes >> visible when you have both high- and low-power devices connecting and >> running on the same supply and have the 0V (DC) connected so that it >> (can) create(s) a loop. >> > > ------------------------------------------------------------------------------ > _______________________________________________ > Emc-users mailing list > Emc-users@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/emc-users ------------------------------------------------------------------------------ Site24x7 APM Insight: Get Deep Visibility into Application Performance APM + Mobile APM + RUM: Monitor 3 App instances at just $35/Month Monitor end-to-end web transactions and take corrective actions now Troubleshoot faster and improve end-user experience. Signup Now! http://pubads.g.doubleclick.net/gampad/clk?id=267308311&iu=/4140 _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
