Emerson Process Management ControlWave XFC - Manual (Page 28)

1-14 / Introduction CI-ControlWave XFC
1.5 FUNCTIONS
ControlWave XFC can come with or without a base application program that satisfies API
21.1 requirements for a meter station using up to two meter runs. Using ControlWave
Designer, the user can readily modify this load to add or subtract functions, increase the
number of runs, etc. An overview of the base application load is provided below.
• Uses pre-configured web pages for user readings, configuration and maintenance. Web
pages can be modified and new pages configured to work with a modified application
load
• Application load is object oriented
• Standard configuration is a two-run station
• Each run can be orifice, turbine or ultrasonic meter type
• Flow calculations include the following:
• AGA3-1985/NX-19
• AGA3-1992 with selectable AGA8 Gross or AGA8 Detail
• AGA7/NX-19
• AGA7 with selectable AGA8 Gross or AGA8 Detail
• Auto Adjust AGA7/NX-19
• Auto Adjust AGA7 with selectable AGA8 Gross or AGA8 Detail
• Instromet Modbus AGA7 with selectable AGA8 Gross or AGA8 Detail
• Daniel Modbus AGA7 with selectable AGA8 Gross or AGA8 Detail
• Includes run switching
• Includes an auto-selector, PID flow/pressure control algorithm per run or per station
• Interfaces to a chromatograph and provides energy throughput as well as composition
information (requires the optional Expansion Communications Module)
• Resides on a BSAP SCADA network
• Supports samplers and odorizers
• Provides audit trail and archives
• Includes a nominations function
• Allows the user to select engineering units, including English and metric
The primary function of the ControlWave XFC is to measure the flow of natural gas in
accordance with API (American Petroleum Institute) and AGA (American Gas Association)
standards. Items below implement and supplement the primary function:
• Data acquisition (see Section 1.5.1)
• Flow calculations (see Section 1.5.2)
• Data archives (see Section 1.5.3)
• Audit trail archives (see Section 1.5.3.4)
• Local display (see Section 1.5.4)
• Communications (see Section 1.5.5)
• Control outputs (see Section 1.5.6)
• Status inputs (see Section 1.5.6)
• Self test and diagnostics (see Section 1.5.7)
1.5.1 Data Acquisition
The process inputs used by the ControlWave XFC are static pressure, differential
pressure, and temperature for orifice measurement, or static pressure, temperature, and
frequency input for positive displacement (PD), turbine, or ultrasonic meters. Static
pressure and differential pressure may be obtained from the Multivariable Transducer
connected to the ControlWave XFC I/O Board assembly. The inputs may also be derived