The gas metering system is the final stage of production before it is sent to the end user of the gas product. It plays a very important role as a custody transfer meter. Every measurement is required to be accurate and with minimum error. This issue (measurement accuracy or error) is very important since it will determine the quantity of the gas price paid by the customer. Gas meters at consumer end measure a defined volume, regardless of the pressurized quantity or quality of the gas flowing through. Temperature, pressure and heating value should be considered to measure actual amount and value of gas moving through a pipeline.
All the data regarding the measured quantity and quality of the gas being exported can be monitored in the Human Machine Interface (HMI) called metering station computer. This computer is the interface between all instrument equipment and the operator. The operator can check the history, print the report, diagnose the flowmeter etc. It also provides interface between the gas metering system with other control system available at the plant such as PCS (Process Control System), ESD (Emergency Shutdown) system etc.