| ??? 09/14/06 18:29 Modified: 09/14/06 18:45 Read: times |
#124325 - answers Responding to: ???'s previous message |
My question was if there were any automatic biasing way of the bus you have ever used or known.
Read 10 best ways ... it is right there http://www.national.com/an/AN/AN-1057.pdf fig 10 on page 10 My second question, (A) switching chips like 4066 or its CMOS versions have substantial switching resistans that changes as with ambient temperature ( typically 25 to 60 ohms) How do you cope with this resistance changes when using this chips during automatic termination. (B) On the other hand, as this chips work as a terminator switcher, they will be exposed to all ESD, unwanted surges, etc.. and are bound to be broken easily and result is a unterminated bus. (A): seek and ye shall find, there are analog switches that could be used was it not for (B) (B): already answered (that is why I use a relay) Erik |
| Topic | Author | Date |
| RS485 and DE, \RE | 01/01/70 00:00 | |
| not pantyhose | 01/01/70 00:00 | |
| Thanks Erik | 01/01/70 00:00 | |
| stick to the National and B&B stuff | 01/01/70 00:00 | |
| the worse 485 wiring | 01/01/70 00:00 | |
| automatic termination is the solution | 01/01/70 00:00 | |
| what\'s that? | 01/01/70 00:00 | |
| its simple | 01/01/70 00:00 | |
| Cool! | 01/01/70 00:00 | |
| hmmm | 01/01/70 00:00 | |
| actually very simple | 01/01/70 00:00 | |
| I am still none the wiser | 01/01/70 00:00 | |
| chain | 01/01/70 00:00 | |
| I've got it. | 01/01/70 00:00 | |
| It works, you work out the details | 01/01/70 00:00 | |
| maybe not biasing A&B... | 01/01/70 00:00 | |
| then use a high enough voltage | 01/01/70 00:00 | |
| biassing | 01/01/70 00:00 | |
answers | 01/01/70 00:00 | |
| if you supply via cable... | 01/01/70 00:00 | |
| Transceiver with switchable termination | 01/01/70 00:00 | |
| thanks for the tip! | 01/01/70 00:00 | |
| great.Oliver, just this | 01/01/70 00:00 | |
| it would, but think this through | 01/01/70 00:00 |