Multiple Touch Screens attached to one PC, each for a different user...

groupware with touch screen or via mouse is off the shelf tech.

http://en.wikipedia.org/wiki/Collaborative_software

I dont think this touch screen is real. its no use one side,

if you hope to get the goal, you can set a fingerprint recongnizer at bottom or some where. so that only authorized people can be allowed to use the screen or computer.

if your computer display two screen at a time, you can control thme by software inside your machine.

Each touchscreen terminal is actually a specialized PC. You can create different application programs for each, different screen displays for each, and different controls for each.

You connect them together either by Ethernet, Modbus, DH+, or whatever so that they can either share data or send/receive data from a central server, PLC or group of PLCs.

The amount of information that you would need is impractical to obtain on this forum only. I suggest you contact a manufacturer or supplier of touchscreen units.

Anything is possible.

In ±1986 we used HP150's with touch screens as terminals to a main frame.

Ok with the first attempts the mainframe came to a halt because we polled the screens too frequently.

I have an old Hercules card and mono screen in a PC. I use it to simulate the communication with a CNC machine when not connected.

With the low cost of PC's is this worth it?

Take a look at the Thinmanger MultiMonitor product. It does not say if it supports touchscreens.

//www.thinmanager.com/index.shtml

A computer manufacture by the name Advent has a line of panel mount computer if it going to be running a window based application. But if you are going to connect the touch screen to a PLC Red Lion has the G3 that will act as a gateway for almost any process controller out. It also has built in web browser that is easy to use. The soft ware for this is a free download. Hope this helped

You are looking for a distributed control system I am assuming. There are many out here that will provide you with both hardware and software for such a system. There is also a large market of software customization companies to fit your every need. Afew of the companies I am awrae of are Fisher-Rosemont, Foxboro, and Lilly (the software company not the drug company).

http://portal.acm.org/citation.cfm?id=502389

lots of links down the page to this exact use