Hi Dave, It all depends on what you want to do. If you just want manual position then the glass scales will do your job.
However, if you ever intend to control the axes then encoders mounted on the end of the ball screws would be my choice. USdigital or Automation Direct (Koyo) encoders are reasonably priced and should do the job. Both my Mazak and my Cincinnati are configured that way. I use the highest resolution I can buy ... 2500 ppr which gives me 10K counts/rev. This, of course, assumes you are going to use servo's not steppers. Using this approach with emc should get you a DRO at less than the 400 UK for the scales and give you an upgrade path into machine control. http://automationdirect.com http://usdigital.com HTH Dave On Jan 31, 2008, at 9:11 AM, Jon Elson wrote: > [EMAIL PROTECTED] wrote: >> Sorry, haven't RTFM, downloading as I type. >> >> I'm considering buying a Far Eastern made 3 axis DRO for my Pinnacle >> universal mill, DRO + 3 glass scales (to 1/5thou") and all cabling >> etc etc >> for under 400 UK Pounds. >> >> This DRO has an RS232 output. >> >> So, does EMC have the facility to take absolute X Y Z positioning >> data >> from the RS232 on the DRO, rather than the traditional method of >> counting >> leadscrew revolutions and subtracting backlash and wear? > If you mean to control the position of a machine as a > closed-loop servo system, using the RS232 output, the answer is > no. EMC by default reads encoder position 1000 times a second. > It is highly unlikely the RS232 output of your DRO updates > more than a couple times a second. Depending on the type of > signals coming from the scales directly, they may be usable. > The position resolution os fairly low, however. I assume 1/5thou > means ~.0002", which is actually 0.005mm Servo control > works a lot better with a higher resolution. > > Jon > > ---------------------------------------------------------------------- > --- > This SF.net email is sponsored by: Microsoft > Defy all challenges. Microsoft(R) Visual Studio 2008. > http://clk.atdmt.com/MRT/go/vse0120000070mrt/direct/01/ > _______________________________________________ > Emc-users mailing list > Emc-users@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/emc-users ------------------------------------------------------------------------- This SF.net email is sponsored by: Microsoft Defy all challenges. Microsoft(R) Visual Studio 2008. http://clk.atdmt.com/MRT/go/vse0120000070mrt/direct/01/ _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
