S7Android allows you to view and change the status of the internal variables of the PLC Siemens S7 family. The connection to the PLC is via Wifi. Tested on: S7-300 S7-400 S7-1200 Logo S120. S7Android use a libnodave-java modify library. As libnodave write: This and other test programs overwrite data in your PLC.
Download the setup package of S7Android 0.55 for free and have a look at users' reviews on Droid Informer. The app runs on Android devices 2.2 and above. This application is completely secure for downloading. Adriano Baronchelli is the creator of S7Android which is included in the Tools category.
Over 10K users set up the app and the most recent update was released on Feb 19, 2015. Users rated this application 3.7 on Google Play. Sony and Samsung users download S7Android quite often.