Peter, I can surely try that although it might be very difficult due to the high gearing. My first reaction was that it was mechanical but then came the argument of "only in one direction" and very predictable and repeatable. I am waiting for my customer to make contact to arrange for me to go to the machine and spend a day there to try and get to the bottom of this. I am going to look very closely at the mechanics first.
On 2013/05/06 05:14 PM, Peter C. Wallace wrote: > On Mon, 6 May 2013, Marius Liebenberg wrote: > >> Date: Mon, 06 May 2013 07:14:34 +0200 >> From: Marius Liebenberg <[email protected]> >> Reply-To: "Enhanced Machine Controller (EMC)" >> <[email protected]> >> To: "Enhanced Machine Controller (EMC)" >> <[email protected]> >> Subject: Re: [Emc-users] Creep in X axis >> >> >>> Are the drives AC servos so the encoder signals are in fact coming >>> from the drives, not the encoder? >>> >> There is an encoder on the motor that is connected to the drive. The >> feedback is then given by the drive. >> >>> If this is the case, is it possible tha the X axis drive is either >>> faulty or improperly setup as regards encoder outputs? >> I have swapped out the drive with one of the working axis. I also >> swapped out the 7i33. There are two in the system and I swapped them >> over. The error stayed with the x axis. >> >> >>> >>> Are you using differential signaling from the drive/encoder to the >>> 7I33? >> >> Yes >> >>> >>> If so, is the 7I33 setup for differential inputs >>> >> Yes >> >>> is the error affected by velocity? (same error if you move at 1/2 the >>> speed?) that is, is it possible you are running into a count rate >>> limitation somewhere? >>> >> There is a huge downward gearing on the x axis and we move very slowly >> as the workpiece can be very heavy. It could be a problem that I will >> have to check out. Why in one direction though? >> >> >>> what is the encoder/drive simulated encoder resolution (counts per MM) >>> and maximum X velocity? >>> >> I am guessing here a bit as I am nit close to the machine at this time. >> The encoder scale is 3500 and max velocity is around 20000 mm/min >> > > Hmm.. this is beginning to look more like a mechanical problem > > Can you mark the motor shaft and check the marks relative position to > the motor case before and after a long move? > > > >> >> -- >> Regards / Groete >> >> Marius D. Liebenberg >> MasterCut cc >> Cel: +27 82 698 3251 >> Tel: +27 12 743 6064 >> Fax: +27 86 551 8029 >> Skype: marius_d.liebenberg >> Skype Me^(TM)! <skype:marius_d.liebenberg?call> >> Get Skype <http://www.skype.com/go/download> and call me for free. >> >> >> >> >> --- >> avast! Antivirus: Outbound message clean. >> Virus Database (VPS): 130505-1, 2013/05/05 >> Tested on: 2013/05/06 07:14:36 AM >> avast! - copyright (c) 1988-2013 AVAST Software. >> http://www.avast.com >> >> >> ------------------------------------------------------------------------------ >> >> >> Introducing AppDynamics Lite, a free troubleshooting tool for Java/.NET >> Get 100% visibility into your production application - at no cost. >> Code-level diagnostics for performance bottlenecks with <2% overhead >> Download for free and get started troubleshooting in minutes. >> http://p.sf.net/sfu/appdyn_d2d_ap1 >> _______________________________________________ >> Emc-users mailing list >> [email protected] >> https://lists.sourceforge.net/lists/listinfo/emc-users >> > > Peter Wallace > Mesa Electronics > > (\__/) > (='.'=) This is Bunny. Copy and paste bunny into your > (")_(") signature to help him gain world domination. > > > -- Regards / Groete Marius D. Liebenberg MasterCut cc Cel: +27 82 698 3251 Tel: +27 12 743 6064 Fax: +27 86 551 8029 Skype: marius_d.liebenberg Skype Me^(TM)! <skype:marius_d.liebenberg?call> Get Skype <http://www.skype.com/go/download> and call me for free. --- avast! Antivirus: Outbound message clean. Virus Database (VPS): 130506-0, 2013/05/06 Tested on: 2013/05/06 09:57:16 PM avast! - copyright (c) 1988-2013 AVAST Software. http://www.avast.com ------------------------------------------------------------------------------ Learn Graph Databases - Download FREE O'Reilly Book "Graph Databases" is the definitive new guide to graph databases and their applications. This 200-page book is written by three acclaimed leaders in the field. The early access version is available now. Download your free book today! http://p.sf.net/sfu/neotech_d2d_may _______________________________________________ Emc-users mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/emc-users
