2012/1/31 Peter C. Wallace <p...@mesanet.com>: > > This can be mitigated by putting a common mode choke (Big > ferrite bead) over the three motor leads (DO NOT include the ground lead)
1) I wrapped each of 3 power wires for motor around a separate ferrite bead. 2) I connected machine frame to common earth ground. > Please try the encoder sample rate lowering example I provided. This will > quickly help to see if there is a noise problem. Noise piked up by the > encoder wires either inductively or capacitively tends to be short pulses. > By lowering the input bandwidth a lot of this kind of noise can be filtered > out. 3) Edited INI file, so that firmware load line is this: CONFIG="firmware=hm2/5i23/SVSTTP6_6_7I39.BIT num_encoders=3 num_3pwmgens=3 num_stepgens=2 enable_raw" 4) Added to HAL file these lines: setp hm2_[HOSTMOT2](BOARD).0.raw.write_address 13312 # = 0x3400 = encoder Sample Rate Register setp hm2_[HOSTMOT2](BOARD).0.raw.write_data 14 # sample rate is clocklow (48 MHz)/SRR+2 # so divide by 16 = 3 Mhz setp hm2_[HOSTMOT2](BOARD).0.raw.write_strobe 1 # do write 5) In "Show machine config" I additionally ran: setp hm2_5i23.0.raw.write_strobe 1 > Here's one way to check for lost encoder counts: > > Mark the shaft and the stator with a pencil/scribe at DRO reading of 0. Move > around a lot or until you have the stall problem, turn off motor power and > hand crank back to DRO 0 and check pencil mark alignment. This should get you > to within a few 10s of counts 6) Scratched a mark in pulley and straight line in motor mounting plate. Aligned so that mark was on the line. Started up Emc. In Hal Meter I opened encoder.0.rawcounts pin, which had a value of 0. Jogged the joint, motor stalled at least 10 times, each time I stopped it with F2, then pressed F2 again, jogged again until it stopped and started to oscillate, so I stopped again with F2 and so on. After a while I turned off motor power (encoder power remained) and aligned the mark and the line (I could not see the screen while doing that). Rawcounts pin had a value -1 7) I tested - jogging bare motor works just fine, which, in case of acceleration lag in encoder, is obvious. The first 5 points were implemented so that all of them were in effect, when last point was conducted. The observed impact of first 5 points - NONE. So my conclusion is - machine is not losing encoder counts, there is no significant noise in encoder signal. Could it be anything else, but the encoder problem? Viesturs ------------------------------------------------------------------------------ Keep Your Developer Skills Current with LearnDevNow! 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-d2d _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
