On-line device testing block integrated into a process control/safety system

Abstract

A process control or safety system within a process plant uses one or more testing blocks to effect the timely and safe operation of on-line testing routines within field devices, such as valves, used in the process control or safety system. These testing blocks, which are easy to implement and to place in the process control or safety system, enable the periodic or on-demand testing of field devices to be integrated into the normal and on-going operation of the process control or safety system without causing scheduling or connection problems and without the need to rely on maintenance or other personnel, thereby providing better monitoring of the operational status of the field devices used within the process control and safety systems. This functionality is especially important in safety systems, in which it is desirable to timely monitor or assess the operational status of the devices used to shut the process down when an unsafe condition arises, so as to assure that initiation of a shut down by the safety system actually results in a shut down of the system.