What is the relation between the real I/O and tags? Are they the same?

Short Answer: Real I/O are tags, but are a subset of the total tag count running.

Explanation: Real I/O with regards to the VTScada license limit represent device addresses read or written via the VTScada communications drivers with tags such as Analog & Digital Status (others too). I/O Tags link to drivers to perform this task. Other tags, such as calculations, context (really cool building block), Fonts, notepads, multiplexer (Again cool!), Totalizer, Selector Switch, etc. (many more) do NOT count against the TAG license limit.

Why was this done? Historically VTScada had ONE price for an unlimited TAG development license and ONE price for a RunTime license with no tag limit. The argument was then made that lower priced licenses were needed \ justified for stations that only 'ran' an application vs. those that created it.

That argument was later expanded to assert that smaller systems should pay less than bigger systems (though the software costs the same to create) as the small system 'value' was lower. Therefore VTScada pricing was organised in tag bands to lower the price for smaller applications so that users would not have to pay for more tags than they needed, and I/O was used the 'yardstick' to measure . Free for 50 tags is pretty good.