On Sun, 15 Mar 2015, Kirk Wallace wrote: > Date: Sun, 15 Mar 2015 07:54:46 -0700 > From: Kirk Wallace <[email protected]> > Reply-To: "Enhanced Machine Controller (EMC)" > <[email protected]> > To: [email protected] > Subject: Re: [Emc-users] VFD causing limits to trip. Huh? > > On 03/15/2015 07:39 AM, Russell Brown wrote: >> >> I promised to report back so... >> >> I fitted the filter (Schaffner FN2030 Series 16A 250 V ac 400Hz) on the >> VFD mains input and that did make a difference. My failing case job ran >> 70% of the way through where without it the job failed 10% in. Not the >> complete solution though. > > ... snip > >> So... finally I replaced the limit switch wires with shielded cable >> (grounded only at the Mesa end). That seemed to do the final trick and >> the job ran all the way through. > > ... snip > > Thank you for posting your results. I'll have to put shielding a little > higher on my list. Don't forget about differential signaling, higher > signal voltage and formal cable termination. > > -- > Kirk Wallace > http://www.wallacecompany.com/machine_shop/ > http://www.wallacecompany.com/E45/
As a general rule ferrite beads help with current noise (ground bumping for example) and are not useful on high impedance inputs while shielding helps with capacitively coupled noise (say from 350V square waves from VFD into limit switch wires) > > ------------------------------------------------------------------------------ > Dive into the World of Parallel Programming The Go Parallel Website, sponsored > by Intel and developed in partnership with Slashdot Media, is your hub for all > things parallel software development, from weekly thought leadership blogs to > news, videos, case studies, tutorials and more. Take a look and join the > conversation now. http://goparallel.sourceforge.net/ > _______________________________________________ > Emc-users mailing list > [email protected] > https://lists.sourceforge.net/lists/listinfo/emc-users > Peter Wallace Mesa Electronics (\__/) (='.'=) This is Bunny. Copy and paste bunny into your (")_(") signature to help him gain world domination. ------------------------------------------------------------------------------ Dive into the World of Parallel Programming The Go Parallel Website, sponsored by Intel and developed in partnership with Slashdot Media, is your hub for all things parallel software development, from weekly thought leadership blogs to news, videos, case studies, tutorials and more. Take a look and join the conversation now. http://goparallel.sourceforge.net/ _______________________________________________ Emc-users mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/emc-users
