The invention relates to a method for joining of a first field device to a wireless sensor actuator network using a configuration tool. The wireless sensor actuator network comprises a plurality of interconnected field devices and gateway for connecting the interconnected field devices to a plant automation network comprising controllers and network manager. The method comprises receiving device information associated with the first field device, transmitting a commissioning request for the first field device, the commissioning request comprising device information and geographical location information of the first field device, receiving commissioning information comprising a session key, a network key and routing information, and commissioning the first field device using the received commissioning information for joining the said field device to the wireless sensor actuator network.