RFID and Plant Automation

If I was to develop an RFID reader with an industrial-type communication protocol, which com type would be the best to have onboard.

Async RS-485?Modbus Ethernet? DeviceNet? Others...???

Before I develop it, which one would be the "best" ONE for deployement in the industries?

I would consider RS-485 for starters. You will need to support Modbus RTU and DF1 full and half duplex. On top of that you might want to support the Omron and GE protocols.

DeviceNet or Profibus DP would be my second choice. These will require more effort but there is only on applicaiton layers.

Support Ethernet if you have the resources to do it right. If you use Ethernet then you will be missing a lot of applications if you don't also support the Rockwell protocols. I am sure our customer use a Rockwell Ethernet protocol over Modbus TCP by at least 5 to 1. Our products supports seven or eight protocols. That will be a lot of work. This is why I suggest that you make a DeviceNet or Profibus DP slave first since you don't need to worry about support many application layers.

Thancks Peter, your input is appreciated.

I have used RFID in plant automation before but they where imbeded in plastic re-used containers. We where using them to manage the flow of base materials on conveyors to feed machines.

Beside inventory controls, where would RFID be most useful?