Had to break for dinner - medium rare scotch fillet, free range eggs and salad - YUM!
Then there is the subject of networks. BMS is
usually LON or BACnet - BACnet is becoming more popular every day. Check here for BACnet -
http://www.bacnet.org/ and here for LON
http://www.echelon.com/.
PLCs use Ethernet, Ethernet I/P, Device Net, Profibus (various flavours), Profibus TCP, Control Net, Modbus RTU, Modbus ASCII, Modbus TCP, Modbus Plus, Controller Link, CompoNet, ASI, Safety Device Net, Safety ASI, Safety Profibus, etc etc. Just about every PLC manufacturer has a proprietary network for example and they are all different.
One of my customers has a very large network of Siemens PLCs on Ethernet to a Citect SCADA system. The Citect SCADA has over 115,000 tags and is very large. IT come in over the weekend and re-program the routers. The SCADA can no longer find the PLCs. A common problem also.
Here are links for a few industrial networks -
www.odva.org www.modbus.org http://ourworld.cs.com/rahulsebos/
The latter one lists most industrial networks and the number in use is mind boggling - and they are not all there.
Then we go to instrumentation - commonly used to interface to PLCs. Thermocouples (many varieties), RTDs, temperature controllers, level measuring devices, pressure sensors, photo electric sensors, etc etc.
And then there are printers, cameras, HMIs, magnetic readers, card readers, VSDs, CNC machines, radio devices, radio communications, satellite communications, etc etc.
Then there is motion control, position control, packing machines, tracking goods on a conveyer, detecting empty bottles/packages, weigh scales, etc etc.
Then there is the very common problem of trying to get a device which uses one protocol to communicate with a device that uses another protocol. The various PLC brands do not generally even communicate with each other over Ethernet.
As I stated, do not get too excited about industrial automation being anything like building automation - it is not!!! Many of us here have spent all our lives in the business and are still learning - and will be till the day we die or retire.
As an example, I spent 5 years as an apprentice, 2 years doing industrial electronics, 4 years doing an electrical engineering certificate, 4 years doing and instrumentation certificate, worked through all of this including getting called out a 2 AM to fix a machine many times, winding motors, machining and re-building commutators, building welders and HV transformers, designing control circuits, designing HV transformers, and on it goes. Many have done far more than I by the way.
I wish you well but, quite frankly, the world of industrial automation is far bigger, more diverse and more complex than building automation will ever be. Building automation is really a piece of cake.