.png?version=1&modificationDate=1559119336894&cacheVersion=1&api=v2&width=423 "Documentation (English) > Connecting Modbus sensors using \"RS485 to USB adapter\" (legacy) > USB485 RS232 RS485 to USB adapter converter (2).png")
"USB485 / Modbus RS485 to USB adapter" is used for connecting Modbus RTU devices/meters/sensors to Vutlan VT325, VT335, VT805, VT825, VT960 series monitoring units.
Please read the article Connecting Modbus devices first.
Sensors are connected in a daisy chain connection.
120Ω resistor is used at the end of the chain.
A twisted pair cable is used for A(+) and B(-).
"RS-485 to USB adapter" has an internal termination and it is switched ON.
The data is transferred to the Vutlan monitoring unit using the USB port.
Up to 31 devices can be used.
Overall cable length no more than 1000 meters.
.jpg?version=1&modificationDate=1557835505416&cacheVersion=1&api=v2&width=747 "Documentation (English) > Connecting Modbus sensors using \"RS485 to USB adapter\" (legacy) > Connecting Modbus devices to Vutlan monitoring units using RS485 to USB adapter (2).jpg")
The same as the first example with the exception that the "RS-485 to USB adapter" does not have a built-in termination.
Termination (120Ω resistor) is added at the start of the chain.
