sensor network

Dear all,

I need ur help for some ideas or websites for sensor networks, from where should I start, and the usefull protocols should be used, and how to connect instrumentations connected with this networks for (4-20 mA).

ant help will be appreciated.

Thanx in advanded

The most common networks for 4-20ma sensors are "Hart" and "Profibus PA"

HART has a good web page describing the differences between sensor, device and control networks:
http://www.hartcomm2.org/hart_protocol/tech_info/eval_networks/compnet.html

4-20mA is usually not considered a network. 4-20mA requires 'home run' wiring, with each device wired all the way from its location back to the controller I/O. 4-20mA devices can't talk peer to peer, they only talk with the I/O point that they're hard wired to. HART digital runs on top of 4-20ma.

Multidrop HART could be considered a device network. It's fairly slow communciation, and it's not peer-to-peer. A web description is here:
http://www.hartcomm2.org/hart_protocol/applications/understanding_hart/multidrp.html
www.hartcomm.org,

Profibus and Foundation Fieldbus are real device/control networks.

For info on Profibus
http://www.profibus.com/pb/technology/description/

Foundation Fieldbus
http://www.iceweb.com.au/Instrument/fieldbus.htm

CAN is used heavily in automotive, but I'm a process guy so I don't know CAN.

Some of A-B's networks are undoubtably device networks, probably DeviceNet, but I'm not an A-B guy, so I could be wrong.

Dan