Is there any way(some free application) to make cell phone to be able to ping my PC LAN address. Since PC and PLC are in same LAN network than my cell phone would be able to ping PLC as well.
The issue you have is that you are trying to ping the 172. ip range while connected to the 10. ip range
Do you know if you have a router managing the traffic between the two networks? Without a router you will not be able to access the PLC from your phone