Simon, Thanks for the tip: I'll have a go at bypassing the isolation board. I'd still like to get closed loop control of the spindle though!
My machine doesn't have a toolchanger I'm afraid. I haven't finished the front panel yet (the only active control is the Estop), but I've been working on a DRO / Jog pendant based on the Arduino. I'm currently stuck with this because I just upgraded the PC to Ubuntu 8.04 and now it won't talk to the Arduino at all from either my Python interface code or from the Arduino IDE. If anyone out there has any ideas or has got Arduino working with 8.04 I'd love to hear from them. Steve > Steve, > > I have a 190 VMC. > The non-linearity is caused by the "Milford Electronics" isolation board > which is bolted to the Lenze speed controller (on my machine anyway) > > I found if I removed that and used the 0-10v direct into the lenze > controller the speed was significantly more linear. > You MUST use an isolated power supply though for your 0-10v converter. DO > NOT be tempted to share the power supply otherwise you will fry your > analogue speed controller (I know I have done it!) > > Does your VMC have a toolchanger? have you implemented that in EMC ? > How have you done the front control panel? > > Hope this helps > Simon > > > ----- Original Message ----- > From: <[EMAIL PROTECTED]> > To: <emc-users@lists.sourceforge.net> > Sent: Saturday, September 20, 2008 12:18 PM > Subject: [Emc-users] Closed-loop spindle speed control > > > >I read with interest the recent thread on Spindle Speed in the hope it > > would answer my question, but it didn't quite get there! > > > > I'm converting a Boxford 190VMC mill to use EMC. I have everything > > basically working but I have been unable to figure out how to get closed > > loop control of the spindle speed. The spindle has a 50ppr encoder and > > is driven by a variable speed drive that wants a 0-10V signal to span > > the range up to 3500rpm. The voltage/speed relationship is quite > > non-linear. > > > > I've hooked up a counter to give me a speed readout via pyvcp. At the > > moment I'm driving the spindle open loop using a lookup table > > implemented with the linear8 Hal component. > > > > But how would I implement closed loop speed control? Is there some > > documentation I've missed, or can someone give me some pointers please? > > > > Steve > > > > -- > > > > > > ------------------------------------------------- > > Visit Pipex Business: The homepage for UK Small Businesses > > > > Go to http://www.pipex.co.uk/business-services > > > > > > ------------------------------------------------------------------------- > > This SF.Net email is sponsored by the Moblin Your Move Developer's > > challenge > > Build the coolest Linux based applications with Moblin SDK & win great > > prizes > > Grand prize is a trip for two to an Open Source event anywhere in the > > world > > http://moblin-contest.org/redirect.php?banner_id=100&url=/ > > _______________________________________________ > > Emc-users mailing list > > Emc-users@lists.sourceforge.net > > https://lists.sourceforge.net/lists/listinfo/emc-users > > > ------------------------------------------------------------------------- > This SF.Net email is sponsored by the Moblin Your Move Developer's challenge > Build the coolest Linux based applications with Moblin SDK & win great prizes > Grand prize is a trip for two to an Open Source event anywhere in the world > http://moblin-contest.org/redirect.php?banner_id=100&url=/ > _______________________________________________ > Emc-users mailing list > Emc-users@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/emc-users ------------------------------------------------------------------------- This SF.Net email is sponsored by the Moblin Your Move Developer's challenge Build the coolest Linux based applications with Moblin SDK & win great prizes Grand prize is a trip for two to an Open Source event anywhere in the world http://moblin-contest.org/redirect.php?banner_id=100&url=/ _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
