| ??? 09/13/06 20:08 Read: times |
#124251 - actually very simple Responding to: ???'s previous message |
Not the simplest, though... But sounds well, thanks!
actually very simple GND on cable/connector pin - is the interconnect on the connector? Visualize ground on pin 2 and the 'sense pin' being pin 1. these are simply connected in the cables plug. The cable connect the 'sense pin' to ground when inserted i.e. one cable = one ground, 2 cables = 2 grounds seen by the unit. If 2 grounds, no termination. The 2 connectors are identical and either can be in or out, if not there would be no gain. And, a bipolar low impedancwe switch - a relay, I guess? Yes, a relay, analog switches could be used, I found some possibles but I have yet to find one that can take the ESD abuse from the wires. Erik let me try this as an illustration of the cable<pre>--00-* sense sense *-00-- | | --00-* ground --------------- ground *-00-- --00 a --\/\/\/\/\/\/- a 00-- --00 b --/\/\/\/\/\/\- b 00-- --00 supply --------------- supply 00-- |
| 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 |