Post by thread:[EE] A<--> Optoisolators (comm) <--> B

Hello, I have two systems A and B. I'd like to have a robust optically isolated communication line (going real time). I have choose RS-232/422/485 as possible communication protocols. I have been searching the net for optoisolators, there are a huge amount of those, but thinking that communication is bidirectional and it could be fast, what are more suitable optoisolators for doing such a thing ? I have been looking to (new) analog iCouplers[1], those look good, but i need good MTBF and good support in the future. Any other good idea ? Thanks ! [1] http://www.analog.com/UploadedFiles/Product_Highlights/619913805627963397963229iCoupler_Brochure.pdf --------------------------------- LLama Gratis a cualquier PC del Mundo. Llamadas a fijos y móviles desde 1 céntimo por minuto. http://es.voice.yahoo.com

Perhaps check out the 6N137 / HCPL2601 / etc. from Fairchild. The datasheet claims 10Mbit/s. -- Martin K Joe Mailer wrote: {Quote hidden}>Hello, > >I have two systems A and B. I'd like to have a robust optically isolated communication line (going real time). I have choose RS-232/422/485 as possible communication protocols. > >I have been searching the net for optoisolators, there are a huge amount of those, but thinking that communication is bidirectional and it could be fast, what are more suitable optoisolators for doing such a thing ? I have been looking to (new) analog iCouplers[1], those look good, but i need good MTBF and good support in the future. > >Any other good idea ? > >Thanks ! > >[1] http://www.analog.com/UploadedFiles/Product_Highlights/619913805627963397963229iCoupler_Brochure.pdf > > > > >

Joe Mailer wrote: > Hello, > > I have two systems A and B. I'd like to have a robust optically isolated communication line (going real time). I have choose RS-232/422/485 as possible communication protocols. > > I have been searching the net for optoisolators, there are a huge amount of those, but thinking that communication is bidirectional and it could be fast, what are more suitable optoisolators for doing such a thing ? I have been looking to (new) analog iCouplers[1], those look good, but i need good MTBF and good support in the future. > > Any other good idea ? > > Thanks ! > > [1] http://www.analog.com/UploadedFiles/Product_Highlights/619913805627963397963229iCoupler_Brochure.pdf > > > --------------------------------- > > LLama Gratis a cualquier PC del Mundo. > Llamadas a fijos y móviles desde 1 céntimo por minuto. > http://es.voice.yahoo.com > You have to be a little bit careful with opto-isolators. They degrade with time, degrade even faster if the IR led is driven hard, so the performance you see initially won't hold up later. --Bob

A transformer is naturally bidirectional you need two optos Just a thought ! Steve -----Original Message----- From: spam_OUTpiclist-bouncesTakeThisOuTmit.edu [.....piclist-bouncesKILLspam@spam@mit.edu] On Behalf Of Joe Mailer Sent: 21 June 2006 18:27 To: Microcontroller discussion list - Public. Subject: [EE] A<--> Optoisolators (comm) <--> B Hello, I have two systems A and B. I'd like to have a robust optically isolated communication line (going real time). I have choose RS-232/422/485 as possible communication protocols. I have been searching the net for optoisolators, there are a huge amount of those, but thinking that communication is bidirectional and it could be fast, what are more suitable optoisolators for doing such a thing ? I have been looking to (new) analog iCouplers[1], those look good, but i need good MTBF and good support in the future. Any other good idea ? Thanks ! [1] www.analog.com/UploadedFiles/Product_Highlights/619913805627963397963 229iCoupler_Brochure.pdf --------------------------------- LLama Gratis a cualquier PC del Mundo. Llamadas a fijos y móviles desde 1 céntimo por minuto. http://es.voice.yahoo.com

I have used with success up to 115200bps a few optocouplers: H11L1, MOC5007 or PC900V. If my memory has no faulty memory locations, all above have an inside trigger schmidth and works with IR currents below 5mA. (H11L1 even with 1mA). success, VAsile On 6/21/06, Joe Mailer <maildmxKILLspamyahoo.es> wrote: {Quote hidden}> Hello, > > I have two systems A and B. I'd like to have a robust optically isolated communication line (going real time). I have choose RS-232/422/485 as possible communication protocols. > > I have been searching the net for optoisolators, there are a huge amount of those, but thinking that communication is bidirectional and it could be fast, what are more suitable optoisolators for doing such a thing ? I have been looking to (new) analog iCouplers[1], those look good, but i need good MTBF and good support in the future. > > Any other good idea ? > > Thanks ! > > [1] http://www.analog.com/UploadedFiles/Product_Highlights/619913805627963397963229iCoupler_Brochure.pdf > > > --------------------------------- > > LLama Gratis a cualquier PC del Mundo. > Llamadas a fijos y móviles desde 1 céntimo por minuto. > http://es.voice.yahoo.com >

Hi Joe, I am not sure what distance you are looking for, but we use fibre-optics. The HFBRXXXX from Agilent(now called AVAGO TECHNOLOGIES) are very easy to use and you can get any size patch cord so no need to do fibre terminations. I use HFBR1414 as TX and HFBR2414 as RX, they are available at farnell and RS. Hope it helps Best regards Luis {Original Message removed}

Interesting matter, do you know any paper that tells about this issue ? I'm not quote sure about iCouplers degrade. Bob Axtell <EraseMEengineerspam_OUTTakeThisOuTcotse.net> escribió: Joe Mailer wrote: > Hello, > > I have two systems A and B. I'd like to have a robust optically isolated communication line (going real time). I have choose RS-232/422/485 as possible communication protocols. > > I have been searching the net for optoisolators, there are a huge amount of those, but thinking that communication is bidirectional and it could be fast, what are more suitable optoisolators for doing such a thing ? I have been looking to (new) analog iCouplers[1], those look good, but i need good MTBF and good support in the future. > > Any other good idea ? > > Thanks ! > > [1] http://www.analog.com/UploadedFiles/Product_Highlights/619913805627963397963229iCoupler_Brochure.pdf > > > --------------------------------- > > LLama Gratis a cualquier PC del Mundo. > Llamadas a fijos y móviles desde 1 céntimo por minuto. > http://es.voice.yahoo.com > You have to be a little bit careful with opto-isolators. They degrade with time, degrade even faster if the IR led is driven hard, so the performance you see initially won't hold up later. --Bob

Joe Mailer wrote: > Interesting matter, do you know any paper that tells about this issue ? I'm not quote sure about iCouplers degrade. > I haven't done much on optos in several years. But there were several papers showing degradation with time and current. I don't have anything on it in front of me. I suggest that you contact Panasonic and ask them about degradation of their PS2501 series, I think that's the last info I saw on it.The problem is in the emitter, not the receiver. --Bob {Quote hidden}> Bob Axtell <engineerspam_OUTcotse.net> escribió: Joe Mailer wrote: > >> Hello, >> >> I have two systems A and B. I'd like to have a robust optically isolated communication line (going real time). I have choose RS-232/422/485 as possible communication protocols. >> >> I have been searching the net for optoisolators, there are a huge amount of those, but thinking that communication is bidirectional and it could be fast, what are more suitable optoisolators for doing such a thing ? I have been looking to (new) analog iCouplers[1], those look good, but i need good MTBF and good support in the future. >> >> Any other good idea ? >> >> Thanks ! >> >> [1] www.analog.com/UploadedFiles/Product_Highlights/619913805627963397963229iCoupler_Brochure.pdf >> >> >> --------------------------------- >> >> LLama Gratis a cualquier PC del Mundo. >> Llamadas a fijos y móviles desde 1 céntimo por minuto. >> http://es.voice.yahoo.com >> >> > You have to be a little bit careful with opto-isolators. They degrade > with time, degrade even faster if > the IR led is driven hard, so the performance you see initially won't > hold up later. > > --Bob >

If you Google "Led Degredation", you'll get about 10,000 hits. But the PDF below pretty well nails it in general terms: http://www.litebeams.com/pdf/caltrans.pdf . --Bob Joe Mailer wrote: {Quote hidden}> Interesting matter, do you know any paper that tells about this issue ? I'm not quote sure about iCouplers degrade. > > Bob Axtell <KILLspamengineerKILLspamcotse.net> escribió: Joe Mailer wrote: > >> Hello, >> >> I have two systems A and B. I'd like to have a robust optically isolated communication line (going real time). I have choose RS-232/422/485 as possible communication protocols. >> >> I have been searching the net for optoisolators, there are a huge amount of those, but thinking that communication is bidirectional and it could be fast, what are more suitable optoisolators for doing such a thing ? I have been looking to (new) analog iCouplers[1], those look good, but i need good MTBF and good support in the future. >> >> Any other good idea ? >> >> Thanks ! >> >> [1] www.analog.com/UploadedFiles/Product_Highlights/619913805627963397963229iCoupler_Brochure.pdf >> >> >> --------------------------------- >> >> LLama Gratis a cualquier PC del Mundo. >> Llamadas a fijos y móviles desde 1 céntimo por minuto. >> http://es.voice.yahoo.com >> >> > You have to be a little bit careful with opto-isolators. They degrade > with time, degrade even faster if > the IR led is driven hard, so the performance you see initially won't > hold up later. > > --Bob >