Automatic initiation and removal of a field device bypass in a process control system

摘要

A control system, or function block, for a process control environment where a processor is in communication with field devices 125, which can be configured in different states, comprises means 132 to receive an input signal from a field device 125 and determine the configuration state of the device 125, and inhibit logic means that automatically produces an inhibit signal when the field device 125 is determined to be in a non-normal configuration state. The inhibit logic may also produce a bypass signal for bypassing the use of further signals from the field device 125 and an override signal for overriding a decision made using a signal from the field device 125. The inhibit logic may automatically remove the bypass signal when the field device 125 is returned to a normal configuration. The system is said to increase safety and reduce the risk of losing product by automatically determining when testing or calibration is being carried out on a field device, and treating signals from that device accordingly.