초록 ▼

Disclosed is a controller having a processor and a control module adapted for periodic execution by the processor and configured to be responsive to a process variable to generate a control signal for a process. An iteration of the periodic execution of the control module involves implementation of

Disclosed is a controller having a processor and a control module adapted for periodic execution by the processor and configured to be responsive to a process variable to generate a control signal for a process. An iteration of the periodic execution of the control module involves implementation of a routine configured to generate a representation of a process response to the control signal. The routine is further configured to maintain the representation over multiple iterations of the periodic execution of the control module and until an update of the process variable is available. In some cases, the update of the process variable is made available via wireless transmission of the process signal. In those and other cases, the controller may be included within a process control system having a field device to transmit the process signal indicative of the process variable non-periodically based on whether the process variable has changed by more than a predetermined threshold. In some embodiments, the field device also transmits the process signal if a refresh time has been exceeded since a last transmission.

대표청구항 ▼

The invention claimed is: 1. A process control system for a process having a process variable, comprising:a field device to transmit a process variable signal indicative of the value of the process variable of the process; and,a controller in communication with the field device, the controller inclu

The invention claimed is: 1. A process control system for a process having a process variable, comprising:a field device to transmit a process variable signal indicative of the value of the process variable of the process; and,a controller in communication with the field device, the controller including a processor and a control module that executes periodically at a periodic execution rate on the processor, wherein the controller receives the process variable signal and the control module generates a control signal for the process based on the most recently received process variable signal;wherein the field device wirelessly transmits the process variable signal non-periodically based on whether the value of the process variable has changed by more than a predetermined threshold so that the transmission time between at least two successively transmitted process variable signals is longer than the periodic execution rate and wherein the control module executes to generate a process response signal representing a process response to the control signal based on an elapsed time between transmission of process variable signals and uses the process response signal to generate the control signal.