On Tuesday 13 November 2012 17:38:24 Viesturs Lācis did opine: > Hello! > > I somehow had skipped the fact that encoders on servos have > differential signal output, but 7i39 cards expect single-ended signal. > Since that is plasma machine with all the noise from plasma, I do not > think that using only half of the differential signal is a good idea. > > I was thinking that I could try making a 422-to-ttl converter, based > on the scheme in top-left corner of this sheet: > http://www.kmitl.ac.th/~kswichit/Rs422/Rs422.pdf That is a good start. In view of the noise, I think I would add a quad of 1n914 type diodes, such that the noise can't rise too far above the 5volt line, or go too far below ground. Two with the cathode bands toward 5v, the anodes to A & B, and two more from a & B with their anodes connected to ground. It might save you a mysteriously blown chip at some point in the future. I would run a shielded line to the encoder without actually connecting the shield to anything at the encoder. The shield s/b well connected to the same ground as the chips gnd pins. The closer the better.
> I just would like to ask, if other list members have some experience > with this - I like to make sure that I am not going to build some > rubish before I have actually taken soldering gun, so I would > appreciate any input on this. Soldering gun? Only used it maybe 5 or 6 times in the last 30 years, for when I needed that level of heat. 99.99% of the time a temp controlled 40-60 watt bench iron, with grounded tips has been used up 10 or so times. I am an old retired TV engineer, and a C.E.T. for 40 years now. That, and about $1.40 should get you a 16oz cup of joe to go at the nearest 7-11. ;-) > Thanks! Cheers, Gene -- "There are four boxes to be used in defense of liberty: soap, ballot, jury, and ammo. Please use in that order." -Ed Howdershelt (Author) My web page: <http://coyoteden.dyndns-free.com:85/gene> is up! Can anyone remember when the times were not hard, and money not scarce? ------------------------------------------------------------------------------ Monitor your physical, virtual and cloud infrastructure from a single web console. Get in-depth insight into apps, servers, databases, vmware, SAP, cloud infrastructure, etc. Download 30-day Free Trial. Pricing starts from $795 for 25 servers or applications! http://p.sf.net/sfu/zoho_dev2dev_nov _______________________________________________ Emc-users mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/emc-users
