Dears friends, what is the maximum number of devices connected by Modbus RTU 485 in a 750-8212?
According to the 750-8212 manual, it supports TIA/EIA 485, which means it supports at least 32-unit loads. Each slave should have a specified unit load based on the chip set it uses, so add up the load of the slaves and if its less than 32, you’re good.
It depends on slaves UL (unit load).If slaves UL is 1/2 then you can connect 64 slaves, if 1/4 UL then 128. TIA-485 specifies that 1/8 UL is possible, but modbus limit this to 247 slave addresses. Probably with so many slaves and line length you should check signal condition with oscilloscope and use power termination if needed.