Patent ID: 6968292

Claim:
A manufacturing system comprising: a plurality of industrial controllers, each industrial controller executing logic establishing at least one queue having a queue length, each industrial controller implementing a time clock, each industrial controller operative detect an event, associate a preassigned event code with the event, read the time clock to obtain an event time, and store as an event record the preassigned event code associated with the event time in the queue; a data communication network interconnecting the plurality of industrial controllers; a group computer connected to the data communication network, the group computer operative to (a) synchronize the time clock in each of the plurality of industrial controllers to the same time at a particular instant of time, (b) for each queue in each industrial controller, store a queue scan rate value and the queue length, (c) for each queue in each industrial controller, retrieve at least one of the event records held in that queue at a periodic interval based on the scan rate value for that queue, (d) accumulate event records retrieved from the plurality of industrial controllers, and (e) periodically forward the accumulated event records; and a server in communication with the group computer, the server operative to receive the forwarded accumulated event records and to store the received event records for access by user interface programs.