Manage the Drag Reducing Agent (DRA) injection rate

The Drag Reducing Agent (DRA) Injector application can calculate the desired injection rate and forward it to the Programmable Logic Controller (PLC) using a setpoint command, if configured to do so. For more information, see Configure the Drag Reducing Agent Injector (DRAInjector) record.

No update to the injection rate is done if the elapsed time since the last update is not more than the configured time required.

The injection rate depends on the desired DRA concentration and the flow rate at the injector.

To manage the DRA injection rate the following occurs:

1. The target DRA concentration in parts per million is read from the configured Target Concentration field.

2. The total flow rate is calculated. For more information, see Understand Invalid Operation checks.

3. The injection rate is calculated:

   

If the difference between the current injection rate and the newly calculated injection rate does not exceed the configured tolerance limit, no update to the injection rate is made. Otherwise, a setpoint command is issued with the new rate (in gallons per hour) to the configured analog.