Patent ID: 7903596

Claim:
A method of operating a wireless mesh network to route messages between a host computer and a plurality of field devices in an industrial process control system, the wireless mesh network having a plurality of nodes capable of transmitting and receiving messages with each node being associated with at least one of the field devices, the method comprising: synchronizing the nodes of the wireless mesh network to a global regular active schedule that defines when messages can be transmitted and received by the nodes; receiving a message from the host computer addressed to a selected field device; identifying based on the message address those nodes required to route the message to the selected field device; activating nodes of the wireless mesh network according to the global regular active schedule; and communicating a message to those nodes identified as required to route the message to the selected field device with instructions to remain in an active state as long as the host computer is communicating with the selected field device, despite the global regular active schedule, which would otherwise cause those nodes required to route messages to the selected field device to become inactive before the communication between the field device and the host computer is complete.