The default web page that was provided actually links to 8 internal relay and the PLC program maps these 8 internal relays to 4 inputs and 4 outputs (see the i-Relay.pc6 program for details). So you can map these 8 internal relays to any I/Os.
The default web page only maps to DM[1] to DM[4]. So in your PLC program you can use these as "window" to change other data inside the PLC (e.g. timer or counter set value, etc).
The virtual LCD in the PLC is also displayed by the web page, so your PLC program can use the LCD to display practically anything inside the PLC and these are automatically shown on the web page.
All that I described above do not require you to modify the core AJAX program residing on the PLC web server in order to access different data in the PLC for different application program. Those really advanced users can rewrite the core routine to access other data they need inside the PLC, since they can issue any Hostlink commands through the Nano-10's "web services" interface to read or write any data inside the PLC. However due to the complication of getting it right we cannot provide tech support for such effort and it should only be attempted by the web programming "gurus".
You can install mulitiple web pages inside the PLC but if they are all using the same core AJAX routine then you are seeing the same data, although they can be of different graphical background and different labels.
What Nano-10 is able to offer is to hide such complication inside the core routine so that average user can quickly and painless create their own unique control web page to read/write to 8 internal relays, 4 DMs and access the virtual LCD. The user's PLC program can then make use of these known data point to provide control to the equipment.
You could for example maps two of the internal relays and use them to select different screen display on the LCD. By clicking on these two buttons you can then activate the PLC functions to display any data that you want to know.
