Productivity is more reliable when equipment can be monitored to detect incipient failures and take corrective action before the plant goes down. But many devices, such as analog control valves, pneumatic valve terminals and field sensors, often do not offer diagnostic feedback, or it is not being used. Information about the health of a control system, the I/O systems, field devices and final control elements can be critical for plant operation and uptime. Timely diagnostic information can mean the difference between a quick repair and hours or days of unplanned downtime. This is especially true of pneumatics and solenoid valves used as air pilots, which are often the forgotten parts of a modern control system
This white paper describes how this problem is being addressed, and includes an example of pneumatic valve terminals that can monitor, among other things, open load or coil currents at the specific valve, pressure inside the valve terminal, and when a manual override has not been reset.