On 5/14/2015 6:53 AM, Tom Easterday wrote: > However, I did find the source of the main problem! It was indeed my > keyboard. Not the USB wiring from keyboard to pc, but the keyboard ITSELF is > very sensitive to the noise created by the VFD. If I move the keyboard to > the very extreme end of it’s (rather long) usb cable the problem disappears > completely. 6” closer to the cabinet and noise reappears. Apparently the > noise is being interpreted as key presses by the keyboard circuitry. I > replaced the new water resistant Logitech keyboard with a very old Apple > keyboard I had lying around and no more random characters! I also had a > second problem where the VFD would shut down somewhat randomly which I > thought was related to this noise as well. That turned out to be an over > current condition at very low rpm. Tweaking some settings fixed that.
Good to know. Apparently Logitech takes the second part of 47 C.F.R. 15.5 (b) literally. "... interference must be accepted that may be caused by the operation of an authorized radio station, by another intentional or unintentional radiator, by industrial, scientific and medical (ISM) equipment, or by an incidental radiator." http://www.gpo.gov/fdsys/pkg/CFR-2014-title47-vol1/xml/CFR-2014-title47-vol1-sec15-5.xml Your VFD is the "incidental radiator". I'd be building a metal window screen box around it. --- This email has been checked for viruses by Avast antivirus software. http://www.avast.com ------------------------------------------------------------------------------ One dashboard for servers and applications across Physical-Virtual-Cloud Widest out-of-the-box monitoring support with 50+ applications Performance metrics, stats and reports that give you Actionable Insights Deep dive visibility with transaction tracing using APM Insight. http://ad.doubleclick.net/ddm/clk/290420510;117567292;y _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
