Power supply in Modbus network

[SORZOM]

Hi Everybody!

Do we always need dedicated power supply in a Modbus network? I'm going to design a Modbus network comprising 15 slaves connected to a AB Micrologix 1100 and couldn't find enough info from Modbus.org and Mirologix manual to verify whether or not I need a separate power supply.

Thanks in advance,

 

[bernie_carlton]

We;'ve never used one. If used it would be at an isolated RS232 -> RS422/485 convertor.

 

[SORZOM]

The confusion came from Modbus manual (Ver. V1-02 available on Modbus.org) where it says the 5..24 VDC power supply is an optional electrical interface which may be added in a 2-wire Modbus network.