On 12 Jun 2014, at 15:49, Peter C. Wallace <p...@mesanet.com> wrote: >> >> As far as I can see the watchdog should bite when linuxcnc is not running, >> switching outputs to high impedance. >> The drives are connected via 330R and an 6N137. >> http://www.uhu-servo.de/UHU_PCB_3_13.pdf >> There is no way they can move on high impedance input. >> They stop moving when I pull the cable from the mesa card. >> The same setup rund without problems using the parport, apart from a few >> steps generated during bootup. >> >> I have another mill with a similar setup, but with a chargepump. >> A chargepump will fix this, but anyway, the mesa card must not output steps >> when Linuxcnc is not running… >> >> Rene > > > The 5I25 will _not_ output steps when linuxcnc does not command them. > I suspect you have an interface problem of some kind. This will probably have > to be resolved with a voltmeter or scope.
It was. the pullups are to big to drive the 6n137. The current was exactly at the switching point, causing them to step very fast. they seem to have no hystereses, the steps are almost invisible on the scope. additional pull-ups helped. maybe it is even better to connect the 6n167 to +5V instead of GND. Thanks, Rene ------------------------------------------------------------------------------ Open source business process management suite built on Java and Eclipse Turn processes into business applications with Bonita BPM Community Edition Quickly connect people, data, and systems into organized workflows Winner of BOSSIE, CODIE, OW2 and Gartner awards http://p.sf.net/sfu/Bonitasoft _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
