I was informed, that there is a APP available for S7-1200 using iPad & iPhone (Siemens Industry @ Twitter)
The application allows you to connect to a Siemens SIMATIC S7-1200.
With this free application you can perform the following tasks:
Connect and identify up to 50 networked CPUs
Change the CPU operating mode (RUN/STOP)
Read CPU and module diagnostic information
Monitor and modify variables or tags
Flash CPU LEDs for identification
It is available in English and German languages.
Necessary firmware: V3.0 or later