I would like to know where can I read more about different specifications like DataHighway Plus, DeviceNet, ControlNet and other communication protocols used to talk to different EXISTING plcs and controllers.

 

Try this link.
"http://www.ab.com/manuals/cn/":http://www.ab.com/manuals/cn/

 

For DeviceNet you can go to
"www.odva.org":http://www.odva.org
"www.ab.com/catalogs/b113/comm/dnet.html":http://www.ab.com/catalogs/b113/comm/dnet.html

For Profibus you can go to
"www.profibus.com":http://www.profibus.com

Since you are talking about an EXISTING plc the first thing you might do is to know what are the protocols supported for these plc’s or controllers.

Sergio Diaz
Momentum Technical Consulting

 

I'm sure a search in the archives give you the same results.
But here are some:
ControlNet "http://www.controlnet.org/":http://www.controlnet.org/

EtherNet IP "http://www.controlnet.org/02a_abenip-cn/index.htm":http://www.controlnet.org/02a_abenip-cn/index.htm
"http://www.ethernet-ip.org/":http://www.ethernet-ip.org/
CANopen "http://www.can-cia.org":http://www.can-cia.org
DeviceNet "http://www.odva.org/10_2/01a_fp_dn.htm":http://www.odva.org/10_2/01a_fp_dn.htm
Modbus "http://www.modbus.org/":http://www.modbus.org/

For all others see "Rob's Fieldbus Pages"
"http://ourworld.cs.com/rahulsebos/Links.htm":http://ourworld.cs.com/rahulsebos/Links.htm

For more CAN related:
"http://www.port.de/engl/publicat/can_links.html":http://www.port.de/engl/publicat/can_links.html
"http://www.port.de/cgi-bin/CAN":http://www.port.de/cgi-bin/CAN

with best regards / mit freundlichen Gr=FC=DFen

Heinz-Juergen Oertel