On Saturday, February 04, 2012 11:38:48 AM Farzin Kamangar did opine: > Dear EMC users, > I have a qestion about spindle brake for touchy interface. If I want > to have a button to use spindle brake and make it on or off, how can I > use the touchy.emc_interface.emc_control to turn the brake on and off? > I need something like touchy.emc_interface.emc_control.spindle_forward > and finally something like: > touchy.emc_interface.emc_control.spindle_brake which I could not find in > the source code. It gives me the error: emc_control instant does not > have spindle_brake > attribute. Could you please help me on that and what should I use > instead? Thanks > Farzin
Farzin: Are you looking to mechanically brake it so as to hold position, or just a way to stop it quicker than letting it coast? My toy's spindle is a DC motor with PM fields so it is just as good at generating power when turning, so my solution was to wire a low ohm power resistor across the backside contacts of the run relay, so that when it was turned off, the resistor absorbed the current it generated. IIRC I used a 20 ohm 20 watt resistor for that, which stops it from full speed in a fraction over 1 second. One could just short circuit it, but that might lead to high enough currents that the PM magnets could be damaged. This is safer for the motor and I have been doing it for about 5 years now. For bigger AC powered induction motors, a 12 volt or so DC power supply, connected to the motors coils for a couple of seconds only, would do a similar job of bringing it almost to a dead stop fairly quickly. Only one set of coils would need to be so driven on a 3 phase motor. For that, even the usual 3 amp cb radio type supply, with maybe 3 ohms at 20 watts for current limiting to protect the supply from the motors low ohms windings could make a quite noticeable difference in the stopping times. A 10 amp supply would be faster for bigger motors. HTH. Cheers, Gene -- "There are four boxes to be used in defense of liberty: soap, ballot, jury, and ammo. Please use in that order." -Ed Howdershelt (Author) My web page: <http://coyoteden.dyndns-free.com:85/gene> I'd crawl over an acre of 'Visual This++' and 'Integrated Development That' to get to gcc, Emacs, and gdb. Thank you. -- Vance Petree, Virginia Power ------------------------------------------------------------------------------ Try before you buy = See our experts in action! The most comprehensive online learning library for Microsoft developers is just $99.99! Visual Studio, SharePoint, SQL - plus HTML5, CSS3, MVC3, Metro Style Apps, more. Free future releases when you subscribe now! http://p.sf.net/sfu/learndevnow-dev2 _______________________________________________ Emc-users mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/emc-users
