Problems related to connecting the modbus RS 485

How to connect the Modbus RS 485 looping for SE Altivar12 and Altivar212 using the RJ-45 connection. I have used Blue and Blue white from RJ45 pin to RS 485 to USB converter to test on Modscan. It always shows device initializing. TIA

Depends on whether your cable and RJ485 are wired with those colors on those pins, I would just pick the 2 middle pins for transmitting/receive as per their diagram on your plug and 2 or 8 for ground. I would think that 5 is positive but if not just swap 5&4 around. I can’t understand how these companies can’t give a pinout that says pin x is ground, pin y is transmitted or + and pin z is negative - it’s not that hard

Blue and Blue/white is conventional colors for pins 4 & 5.

The problem with EIA-485 is that the standard does not define which is A which is B and some vendors label the pins one way, other vendors label the pins the opposite. So although one is supposed connect (+) to (+), (-) to (-) or A to A, B to B or, D1 to D1, D0 to D0, sometimes it’s backwards, between vendors. Just an anomaly of RS-485.

As Ashlin says, if it doesn’t work, try swapping the leads on one end and see if that fixes it.