On May 27, 2012, at 11:21 AM, Kirk Wallace wrote: > On Sat, 2012-05-26 at 23:31 -0500, Jon Elson wrote: > ... snip >> Jeshua's AMT-103 encoder has a 2 mA source/sink driver when used by >> itself (without >> the line driver cable option). So, you can't apply too much of a >> pull-down or it will >> alter the logic levels. > > This is getting messy. I made a first attempt at a schematic of a single > encoder setup. It should be attached. Also, the Inkscape SVG file is > attached if someone wants to edit it. There are some missing bits, such > as, how each component gets powered and grounded. I assumed the driver > cable is used because 2ma just doesn't seem enough to drive the inputs > well. Another message indicated an AMT102, so I used that, but makes > little difference.
Hi Kirk, Thanks for all your help! I would be happy to float you some PayPal dough for your time. But I am actually not using the AMT line driver cable. I think Jon may have got that idea because I mentioned I had installed a differential encoder/decoder, but it was from CNC4PC. I guess it is mostly the same, but in any event I removed it because the drive was acting so erratic with it. I now think it was interference in the cabinet, but not sure if I need to wire up the differential again, as it seems pretty noise free now and starting to look like it is actually a tuning issue at this point... >> It should be possible to read the logic levels >> with a DVM by >> very gently moving the motor and letting it settle, you should be able >> to see both the >> high and low logic levels. The Universal Stepper Controller has about a >> 2.5 V >> logic threshold, the Gecko interface uses a PNP emitter follower driving the >> opto-coupler's LEDs, but the threshold there also is about the same. > > The USC encoder inputs go directly to the FPGA or a buffer? Any > hysteresis? Any pull ups? > > The Gecko encoder inputs go directly to a PNP base, maybe with a voltage > divider? Any hysteresis? Pull ups? I suppose these questions are for Jon as I don't have a clue! Thanks again, Jeshua Lacock Founder/Engineer 3DTOPO Incorporated <http://3DTOPO.com> Phone: 208.462.4171 ------------------------------------------------------------------------------ Live Security Virtual Conference Exclusive live event will cover all the ways today's security and threat landscape has changed and how IT managers can respond. Discussions will include endpoint security, mobile security and the latest in malware threats. http://www.accelacomm.com/jaw/sfrnl04242012/114/50122263/ _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
