Accurate flow control at low cost
12 Jul 2001
The Starling Associates gas flow loadable function block for electronic flow measurement allows gas flow calculations to be performed in a PLC, eliminating the need for a separate, standalone flow computer.
Kenneth Starling, who wrote the flow equation code that is accepted by the American Gas Association (AGA), has now replicated the code for Schneider Electric.
The gas flow computation software is available for select models of Modicon Compact and Micro controllers. It runs in 984 ladder logic and is compatible with Modsoft 2.5 or higher, Proworx NXT and Concept PLC programming software. It's also compatible with Meter Manager software available from Starling Associates.
The function block meets the requirements of AGA 3 for orifice plate meters and the AGA 8 and NX-19 compressibility equations used for special gas compositions. It also conforms to the American Petroleum Institute (API) audit trail and event log requirements for custody transfer.
