| ??? 10/22/08 09:17 Modified: 10/22/08 09:22 Read: times |
#159253 - But it truly should... Responding to: ???'s previous message |
K. said:
However, the external RS485 device has no provision to connect Ground line. The external RS485 device belongs to a "large" "reputed" manufacturer and they feel that lack of ground connection can not be the reason for failures as it is working in installations in some other parts of the world! Of course, but remember that you told The earthing on the 230V supply point is not good and some times a voltage of 90+V is found between Neutral and Earth. With such huge common mode interference you cannot omit the signal ground connection in the RS485 interface! The next failure you observe can be the RS485 transmitter, if the common mode interference is really that huge... Yes, I know, not the RS485 transmitter has failed but the RS232. But let me tell you, that I have learned over the years, that interference taking place at the one point can have influence on a different point, even if you might not understand how, at the first moment... Kai |
| Topic | Author | Date |
| MAX232 failure | 01/01/70 00:00 | |
| MAX232 failure | 01/01/70 00:00 | |
| Does that mean, ... | 01/01/70 00:00 | |
| Yes, ground is not connected | 01/01/70 00:00 | |
| exactly what is connected to the MAX232... | 01/01/70 00:00 | |
| But it truly should... | 01/01/70 00:00 | |
| Thanks for your suggestion | 01/01/70 00:00 | |
485/232 with 'unreliable' ground | 01/01/70 00:00 | |
| It is a handheld terminal | 01/01/70 00:00 |