On Fri, 14 Mar 2008, Howard Chan wrote: > Date: Fri, 14 Mar 2008 01:15:01 +0800 > From: Howard Chan <[EMAIL PROTECTED]> > Reply-To: "Enhanced Machine Controller (EMC)" > <emc-users@lists.sourceforge.net> > To: "Enhanced Machine Controller (EMC)" <emc-users@lists.sourceforge.net> > Subject: Re: [Emc-users] Can EMC2 support any 'AC Servo Motor'? > > Dear Peter, > > Would you explain detailed about why using the analog velocity input is > better then pules/direction? > Thank you!! > > Howard
Step and direction interfaces are usually used for simple systems without a fully closed position loop (like step motor systems). While its theoretically possible to use the encoder feedback with step and direction, its not as direct as velocity or torque drive. Another disadvantage of step & direction drives is that now you have two feedback PID loops to tune, the amplifiers PID loop and EMCs PID loop. My personal experience is that having the control locus in one place makes tuning easier. Also with step and direction servo amplifiers its likely you would need hardware step generation to reach the full speed capabilities of the drives. In addition you may need two separate operating systems to tune the system, typically Windows to tune the amplifiers PID loop and Linux of course for tuning EMCs PID loops. One general advantage of using EMC for the total control loop (as you would do using the amplifiers torque input and EMC for the PID loop), is that now all of the motion control code is open and changeable. This may be especially important as this is a university project. (no 'black boxes'!) Peter Wallace Mesa Electronics (\__/) (='.'=) This is Bunny. Copy and paste bunny into your (")_(") signature to help him gain world domination. ------------------------------------------------------------------------- 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