This forum uses cookies
This forum makes use of cookies to store your login information if you are registered, and your last visit if you are not. Cookies are small text documents stored on your computer; the cookies set by this forum can only be used on this website and pose no security risk. Cookies on this forum also track the specific topics you have read and when you last read them. Please confirm whether you accept or reject these cookies being set.

Wiser for KNX and modbus problem
#21
Ideas anyone? It seems almost that the slave 8 (but 9 is the same) respond as slave 130...I see a sort of pattern here since slave 8 and 9 are two PM3250, but I can't find any sense in that behavior...
Reply
#22
The communication errors are caused by cabling, topology and/or noise sources that affect the signal quality. Another possibility is a damaged RS-485 chip on one of the devices. If real-time data acquisition is not needed then some errors during communication are acceptable.
Reply
#23
Topology is correct (we even undo that short branch), cabling I assume it's the same since we use certified cables, could be some noise but with twisted pairs, terminating resistors and signal grounds I don't see how.

Thanks for help anyway, I think that it's the best that we can provide in this situation.
Reply
#24
Two weeks ago I was helping in one installation. 16 slaves where two were the PM3255 you have. Everything just worked but the cabling was spot on. If you are confident about cables I would disconnect all slaves and try them one by one.
Reply


Forum Jump: