On 13.11.12 22:37, Jon Elson wrote: > Viesturs Lācis wrote: > > 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 drawing uses some very old parts, and may no longer be obtainable. I've > been using AM26C32 receivers in several boards and they work well and are > good up to encoder frequencies. You should have a 100 - 120 Ohm terminating > resistor at the receive end, between the + and - signal lines.
Yes, and those old parts are annoyingly current hungry. Even the DS26LS32A draws 50 to 70 mA. Jon's AM26C32 is better - 10 to 15 mA, and it's good to +/- 14v input. (The RS485 permitted common mode is only 7v, so that should be ample, I figure.) Then there's the MAX3095EPE, which consumes only 2.4 to 3.5 mA. It's also good for +/- 25v input, and 15 kv ESD, according to the datasheet. Around hot machinery, I wouldn't use a commercial chip (0° to -70°C), only industrial (-40° to 85°C) or better. I'm about to order a few MAX3095EPE for the current project, but have milled out the front panel tonight, instead of finishing the parts list for the electronics. Digi-Key has them, in DIP16 and SOIC16 and several temperature grades. Erik -- "The cigarette is the deadliest artefact in the history of human civilisation," says Robert Proctor of Stanford University. "It killed about 100m people in the 20th Century." - http://www.bbc.co.uk/news/magazine-20042217 ------------------------------------------------------------------------------ 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
