Image Number 3 for United States Patent #7783330.
A host computer communicates with field devices over a wireless network that includes a gateway and a plurality of wireless nodes. At least one of the field devices is associated with each wireless node, and each field device has a unique field device address. The host computer sends control messages to field devices using their field device addresses. The gateway translates the field device address of a control message to a wireless address of the wireless node with which the field device is associated. The gateway sends a wireless message over the network to the wireless node at the wireless address. The message contains the field device address so that, when the wireless message is received and opened, the control message from the host computer can be routed to the intended field device based upon the field device address.