Use a differential pressure instrumentation function to measure flow

You can measure flow using a primary flow element and a differential pressure function. To do this, reclassify the flow instrumentation function as a differential pressure instrumentation function. User expertise is required to correctly classify the function according to the type of in-line object used as the primary flow element.

Prerequisites

Create a flow measurement in P&ID

Use a differential pressure instrumentation function to create a flow measurement

1. Select the flow instrumentation function, and then select Reclassify and set it to the Differential Pressure Instrumentation Function class.

   

   The differential pressure instrumentation function object provides access to the main components of this measurement configuration, including the flow sensor (primary element), pressure sensor, and pressure transmitter. If a flow instrumentation function object is not reclassified, these components are not available as valid options for creation.

2. ENG.INST: Set the Sensor reference by entering the tag number of the flow sensor (displayed in the Related Instruments column) in the Sensor column.

   

   The Instrumentation user now has access to the relevant primary flow element used in the flow (Differential Pressure) measurement datasheet specification.

Add a pressure element

Add Pressure Element part to translate the differential pressure produced in the pipeline.

3. Drag and drop the Pressure Element part from the from the Instrumentation – Instrument Function Parts palette onto the canvas, and then select the item the element belongs to.

   

   The value automatically appears in the Sensor (DP) column.

   

Add a pressure transmitter

4. Drag and drop the Pressure Transmitter part from the from the Instrumentation – Instrument Function Parts palette onto the canvas, and then select the item the element belongs to.

   

   The value automatically appears in the Transmitter (DP) column.

   

   Note: Since the Transmitter column references a Flow Transmitter which is not relevant for this type of object, it does not need to be populated.