| ??? 06/13/06 12:03 Read: times |
#118218 - you missed one Responding to: ???'s previous message |
1. You must always transmit both signal lines AND signal ground!
2. The two signal lines (+D and -D in your example) must be transmitted via a twisted pair. 3. Characteristic impedance of this tiwsted pair and the added termination resistances must match. In your case a twisted pair showing 120Ohm is needed. 4. Termination resistances must be present at both sides of RS485 cable, means directly at the driver and directly at the reciever! 5. ultra short stubs. a rewrite of 4 (which I initially misread). Termination resistances must be present at both ends of RS485 cable, means directly at the driver and directly at the last reciever! Erik |
| Topic | Author | Date |
| Bad MAX 485 IC ? | 01/01/70 00:00 | |
| Voltage between Earth and Neutral.. | 01/01/70 00:00 | |
| also | 01/01/70 00:00 | |
| This may be one reason | 01/01/70 00:00 | |
| What's a DB9? | 01/01/70 00:00 | |
| Correction . DE9 - not DB9 | 01/01/70 00:00 | |
| Earthed Shell to the shield of cable | 01/01/70 00:00 | |
| Mild shocks... | 01/01/70 00:00 | |
| E1 is a pump controller | 01/01/70 00:00 | |
| Open "E1" and have a look at | 01/01/70 00:00 | |
| you missed one | 01/01/70 00:00 | |
| Only one reciever | 01/01/70 00:00 | |
| Yes. Only one receiver | 01/01/70 00:00 | |
all uC developers should be Boy Scouts | 01/01/70 00:00 |