<![CDATA[RS485T and ACSOCKET and 120 OHM RESISTOR]]>As I understand 120 Ohm terminated resistor for RS485 bus will be used only in one single end of the bus. I wonder if RS485T integrate R120 ohm and we connect many of them together, the data might be incorrect. I test with AC Plug if I don't use the RS485T the RX response is correct as in attached picture. After testing AC Socket for a while I found that if there is only one 120 Ohm terminate resistor on the bus, sometimes the Rx response is incorrect.
Anyone face the same problem?
0_1584616724744_R120Terminate_resize.jpg

]]>https://community.m5stack.com/topic/1777/rs485t-and-acsocket-and-120-ohm-resistorRSS for NodeWed, 29 Apr 2026 19:11:47 GMTThu, 19 Mar 2020 11:20:31 GMT60<![CDATA[Reply to RS485T and ACSOCKET and 120 OHM RESISTOR on Fri, 20 Mar 2020 07:45:48 GMT]]>@aehiot said in RS485T and ACSOCKET and 120 OHM RESISTOR:

As I understand 120 Ohm terminated resistor for RS485 bus will be used only in one single end of the bus. I wonder if RS485T integrate R120 ohm and we connect many of them together, the data might be incorrect. I test with AC Plug if I don't use the RS485T the RX response is correct as in attached picture. After testing AC Socket for a while I found that if there is only one 120 Ohm terminate resistor on the bus, sometimes the Rx response is incorrect.
Anyone face the same problem?
0_1584616724744_R120Terminate_resize.jpg

I asked about this before but have been too busy to do any test with the 485 units.
If you are interested in continuing test, please let us know.
Also please consider creating a project log in hackster.io and record you discoveries.

]]>https://community.m5stack.com/post/7837https://community.m5stack.com/post/7837Fri, 20 Mar 2020 07:45:48 GMT