2013/1/8 Peter C. Wallace <p...@mesanet.com>: > > Sounds like you have a severe noise issues, which is not terribly surprising > with 11M motor cables. > > First thing I would do would be to add a common mode choke around the U/V/W > Motor wires at each 7I39 end of the motor cable: Laird-Signal Integrity > Products 28B1122-100 is a good choice here.
Ok, I will try to find some place, where to obtain ferrite rings. One shop did not have them, the others were already closed, so I will try them tomorrow morning. I guess that visiting places that fix different electronics stuff also might work - they might have something to pull these things out, so I will try my luck finding some of them as well. > Another thing to do is increase the encoder filtering if you have not already > done this: > > See the hostmot2 manual page, raw mode section (you need to enable > raw-mode) > > Don't know if there's a HAL example of using raw-write but here's an > approximation: > > setp hm2_[HOSTMOT2](BOARD).0.write-address 13312 # (0x3400) > setp hm2_[HOSTMOT2](BOARD).0.write-data 8 (divide/10) > setp hm2_[HOSTMOT2](BOARD).0.write-strobe TRUE I added enable_raw to config string right after number of encoder modules to be loaded in top of ini file and copied the above 3 lines in main HAL file. The thing is that I receive error message that pin hm2_5i23.0.write-address is not found. I tried also write_address instead of write-address, but still the same. Any ideas? The encoder has 4000 PPR and motor will not spin faster than 50 revolutions per second, so that is 200 kHz max count rate. I guess that adding a little safety margin would be smart, so what write_data value I need to set filter time constant at 6 usec? > Other things > > Shielded motor wires Not implemented. I did not find any 4-lead multistrand wires with shielding, where each lead would be at least 0.5 mm^2. So I went for unshielded 0.75 mm^2 4-lead wires. What is the idea behind it? To prevent noise being induced in motor wires or to keep noise being induced by the current in motor wires? I mean - keep the noise out of motor wires or keep it inside and not let out? > shielded encoder cables (differential signals on twisted pairs) shield > terminated at 7I39 (differential adapter) end and open at motor end Both of them are implemented - encoder signal is differential, cable is shielded, connected to ground on a clamp right on case of control box - that is the point, where all the ground wires meet. > Forgot to say: the Hall wires should also be shielded > and since they are single ended you may need to add a > .1 uF capacitor from each Hall pin to Gnd at the 7I39 end > of the cable It already has a shield - they are share the same cable with encoder signals. I will try to find a place to obtain capacitors. 2013/1/8 Bruce Layne <linux...@thinkingdevices.com>: > The first thing I'd do is get a digital storage > oscilloscope and observe all of the signals - motor power, Hall effect > signals, encoder signals, any control signals. I have been thinking about purchase of oscilloscope for a long time. So far their pricing have seemed too much for me, so I have not obtained it and unfortunately have insufficient funds to do it now. Thanks for the reminder though! I guess that having oscilloscope would allow me to see, where exactly the noise is - is it hall signal, encoder or whatever else... -- Viesturs If you can't fix it, you don't own it. http://www.ifixit.com/Manifesto ------------------------------------------------------------------------------ Master SQL Server Development, Administration, T-SQL, SSAS, SSIS, SSRS and more. Get SQL Server skills now (including 2012) with LearnDevNow - 200+ hours of step-by-step video tutorials by Microsoft MVPs and experts. SALE $99.99 this month only - learn more at: http://p.sf.net/sfu/learnmore_122512 _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
