Jon, Thank you for the information. These are Glentek amps. How can I be sure that they take +-10v velocity command signals? The schematics show the motors as tach motors. I am going to be looking at various options to do this. I would like to end up with a machine that has smooth motion, have decent resolution, and be reliable when done. I will be looking into the pico-system products. I appreciate your assistance. Terry
On Thu, Jul 1, 2010 at 10:30 PM, Jon Elson <[email protected]> wrote: > Terry wrote: > > Has anyone done an upgrade on a mid 80's Bridgeport mill with a Pro Trak > > control? I have one that has Gentek DC servo's and amplifiers. The > > machine has servo motors on all three axis and they work fine but I > > would like a more modern set up. I have the schematics and manuals. The > > manual says that the amps work using Pulse Width Modulation. I'm not > > sure what it uses for signals. I have seen in forums that others have > > used Mesa boards and EMC to retro older controls using the original amps > > and motors. I am a Linux fan, I use it as my primary O.S., but no > > expert. I am no electronics expert either. Others have made it sound > > easy. Would a experienced machinist like myself be able to tackle this? > > > I make a complete lineup for systems like this. Those are Glentek servo > amps? > I assume the motors have tachometers? The servo amps almost certainly > take +/- 10 V > velocity command signals. > > So, there are two paths. One is to keep the servo amps and use my PPMC > board set > which produces the analog command output. The basic set is $780, and > provides pretty much everything > you need. > > The other way it to get rid of the servo amps, and use my universal PWM > controller and my > PWM servo amps. That runs about $625. Really, the best way is to keep > the servo amps if they are working well, you get smoother motion with a > velocity servo than with the low-resolution encoders and no velocity > info you'd get > with the digital PWM servo amps. > > Mesa looks a lot cheaper at first than the Pico Systems stuff (my > company), but they require daughterboards, breakout boards, cables, etc. > so the price difference gets much less. > > You can check out my boards at > http://pico-systems.com/oscrc4/catalog/index.php > check the categories of PPMC and PWM Servo. > > Just to be sure, does this machine have digital encoders, or resolvers > on it? (I can provide the hardware > to go either way, but the encoders are simpler.) > > Well, converting a CNC machine with stepper motors is "easy", but there > are limitations such as no position feedback to detect jams/crashes. > Servos are a bit more complicated. The wiring is just a little more > complicated, although if you keep the servo amps, it really isn't much > more, you just need to be careful to not rip out what you intend to > keep. But, then you have to "tune" the servo response. EMC2 has a LOT > of helpful features, such as HalScope to help you do this, but you have > to learn to use these facilities. When you get done, though, you have a > machine where you can PROVE the responsiveness and accuracy of motion, > and go back and recheck any time you think it may be misbehaving. I am > using the PPMC on my Bridgeport mill. It was a manual mill, and I had > to adapt ballscrews and motors to it. > > Machining skill may not be greatly useful here, it will be mostly wiring > and tweaking the configuration files. At least you don't have to fight > the Linux learning curve, that's what stops so many Windows users. > > > Jon > > > ------------------------------------------------------------------------------ > This SF.net email is sponsored by Sprint > What will you do first with EVO, the first 4G phone? > Visit sprint.com/first -- http://p.sf.net/sfu/sprint-com-first > _______________________________________________ > Emc-users mailing list > [email protected] > https://lists.sourceforge.net/lists/listinfo/emc-users > ------------------------------------------------------------------------------ This SF.net email is sponsored by Sprint What will you do first with EVO, the first 4G phone? Visit sprint.com/first -- http://p.sf.net/sfu/sprint-com-first _______________________________________________ Emc-users mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/emc-users
