Kindly, 

Are the  WIFI  ,  LAN port P1  ,  LAN port P2  ,  three isolated networks in the Field PG M5 ? 

Also, is the IP address range 192.167. usually free to use ? 

Thank you 

https://w3.siemens.com/mcms/industrial-automation-systems-simatic/en/rugged-laptop/field-pg-m5/pages/default.aspx

Hello,

yes 3 isolated Networks.

If you can use the IP depends on the network you connect the PG.

Regards

Christoph