VBA (zero) 15, 6v DC; Offset Too High for RS485?


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Hello colleagues,

I am refurbishing an rs485 installation which also supplies power to an LCD controller. I want to replace it with a more modern controller.

I have measured a voltage Vba from slave in zero state. It turns out to be 15`6V between B and A.

Is too high? The highest numbers are -7 to 12V in standards. I know that this offset is used to power the existing LCD controller.

The new controller I try to incorporate is a max485. Will it be OK if I connect it directly to the max485? If not, what can I do to reduce such 15,6v offset without impairing communications?

Thanks for your wise advice.