Maybe my english is very hazy. I mean that there is PLCsim. It is program than can simulate CP card and PLC. It is like-> you run PLCsim, it is launched and represents you window where you can set MPI address, stop, run, reset memeory and etc for virtual PLC, and you can get many small window that has checkboxies. These windows represent you memory, datablok byte, word, etc, address, DB registers, ACCU1 and ACCU2 or ACCU1-ACCU4 in case if you have S7-4XX in your project. You must download your project to virtual PLC bevore you can monitor and etc. I hope that anybody PLCs men heard about program like this one.