I have been looking again at the libnodave library for Siemens PLCs, it provides a dll that can be used in VB.Net that gives:
A free communication library for Siemens S7 200/300/400 via
' the MPI adapter 6ES7 972-0CA22-0XAC
' or MPI adapter 6ES7 972-0CA23-0XAC
' or TS adapter 6ES7 972-0CA33-0XAC
' or MPI adapter 6ES7 972-0CA11-0XAC,
' IBH/MHJ-NetLink or CPs 243, 343 and 443
' or VIPA Speed7 with builtin ethernet support.
' or PPI access for the S7-200 (I know you have a driver well in hand)
That lot covers Siemens MPI, PPI and ISO over TCP/IP for S7200/1200/300/400. It would be a major boost to the userbase for Advanced HMI.
Would you be OK if I got a programmer friend to try to make these communications drivers available to Advanced HMI. I will understand if it is a problem, Advanced HMI is your baby and you may not want other people messing with it.