| ??? 12/03/04 03:15 Read: times |
#82446 - RS485 contention Responding to: ???'s previous message |
The only answer that I can suggest is to have RE disabled also and controlled by another port pin. When your app eventually fires up, it enables the receive. This is probably similar in intention to Alberto's suggestion. As for optocoupling the 485 interface - I'm in two minds. My earlier gear wasn't optocoupled and have deployed over 500 units all in an industrial situation and with >100m cable lengths in environments ranging from sub zero to middle east temps >55c and tropical lightning prone areas. The major problems have been with wiring. My later models have optocoupling but this has not made anything necessarily more reliable. What's interesting to note is that many PLC's don't bother to use optocoupling. To opto couple or not to optocouple... that is the question!!!!!! |
| Topic | Author | Date |
| RS485 Contention. | 01/01/70 00:00 | |
| 485 ISP | 01/01/70 00:00 | |
| RS485 'U' & ISP | 01/01/70 00:00 | |
| the crux | 01/01/70 00:00 | |
| Flashmagic !!!! | 01/01/70 00:00 | |
| RS485 contention | 01/01/70 00:00 | |
| Cygnal F12x | 01/01/70 00:00 | |
| Reply to Erik | 01/01/70 00:00 | |
| FM< half duplex | 01/01/70 00:00 | |
| Reply to Erik | 01/01/70 00:00 | |
| bus direction | 01/01/70 00:00 | |
| A few comments | 01/01/70 00:00 | |
| comnments on comments | 01/01/70 00:00 | |
| comments^3 | 01/01/70 00:00 | |
| boot NIT | 01/01/70 00:00 | |
An example worth 3E8h words :-) | 01/01/70 00:00 | |
| A fundamental query - Erik | 01/01/70 00:00 | |
| testing | 01/01/70 00:00 | |
| RS 485 Contention | 01/01/70 00:00 | |
| RS485 Contention | 01/01/70 00:00 | |
| Switch ? | 01/01/70 00:00 | |
| RS485 contention | 01/01/70 00:00 | |
| Possible solutions. | 01/01/70 00:00 | |
| Thanks Erik. | 01/01/70 00:00 | |
| SOLUTION | 01/01/70 00:00 | |
| Thanks but thats not the solution | 01/01/70 00:00 |