Meter Proving or Batch Operations with the Realflo Flow Computer
The Realflo flow computer software, which may be loaded onto a SCADAPack RTU (standard or x70 types), is able to provide Batching or meter Proving capabilities. This is configured on the Batch tab in a flow run configuration. (either Liquid or Gas)
Batching refers to measurements taken over a specific period of time. This may be done in order to transport several different products along a single pipeline, and through the same metering facility. Or it may be done for meter Proving, which is a procedure done both to ensure proper operation of a flow meter and to calibrate its output to a known external standard.
Configuration of the Batch tab is straightforward. First, the user is prompted to enter a QTR Identifier. This is the Quantity Transaction Record Identifier, used to identify the meter used as well as the historical data and information for the measured batch, as recorded in Realflo's logs.
Next, a Batch Trigger may be enabled. This typically would be required. Enabling the Batch Trigger allows the user to enter a Batch Trigger Register, which is used to start and stop the Batch or meter Prove in Realflo. A Modbus coil or status register may be used for this purpose, or a database object if in the x70 RTU. The batch starts when the input transitions ON, and ends when the input transitions to OFF.
A new Batch ID is created for each OFF -> ON transition, and the batch data is stored in the RTU's batch history records. For more detailed information on Batch operations, refer to the Realflo User Manual, in the Expert Mode Batch Operation section.
It may be necessary to write logic in the RTU to drive the Batch Trigger register. Alternately, this register may be controlled remotely from an HMI or SCADA Host application.
Joel Weder Telemetry Solutions Specialist Schneider Electric