Hello people...
Is normal to loose communication with all devices In a modbus rtu network when one of the devices is turned off?

 

depends on what the interface IC of the device does when switched off. normal people would design it in such a way, that the outputs connected to the modbus A and B lines goe in 3-state, but you never know....
Depends on the electronic design.

 

So, the modbus protocol or fiscal layer RS485 standard doesn't specify anything about this?