Batch control: Next generation controller targets hydrocarbon-liquids measurement accuracy

The DL8000 is a new microprocessor-based batch delivery controller from Emerson Process Management.

By Control Engineering Staff January 8, 2008

Changing industry standards, the high cost of hydrocarbon products, and the need to manage operation costs fueled the development of a new microprocessor-based batch delivery controller from Emerson Process Management. The DL8000 is the next generation of Emerson’s DanLoad line of Preset Controllers, designed to resolve batch control requirements for liquid custody transfer applications.Preset controllers accurately set the amount of liquid to be delivered and loaded into a truck, railcar, or ship, and control the valves and pumps to load the liquid while monitoring critical circuits to ensure safe loading. These processes must all meet standards set by the American Petroleum Institute (API), which continually updates its measurement standards.According to Emerson, the DL8000’s enhanced accuracy comes from the capability for double-precision math computations supplied by Emerson’s Fisher ROC-Series remote operations controller technology. This not only satisfies API requirements, but also provides extremely accurate measurement and reliable control, local or remote, according to the company. Because hydrocarbons expand and contract with changes in temperature and pressure, converting the flow measurement to standard conditions provides a more accurate measurement. The DL8000 calculates flow for custody transfer using average measured product flow rates, measured temperature, pressure, and density to achieve a measurement of flow at standard conditions. This conversion capability reportedly provides potential savings of million of dollars over time.The DL8000 is easy to configure for different batch loading applications using Emerson’s ROClink 800 software and is fully programmable for PLC tasks using function sequence tables (FST) or any of the languages defined by IEC Standard 61131-3, including ladder logic, structured text, function block diagrams, instruction list, or sequential function chart language.According to the company, connectivity of the DL8000 to Emerson’s DeltaV Process Control Systems with ROConnect enables the customer to drive maximum benefit, performing remote device diagnostics using Emerson’s AMS Suite predictive maintenance software. This improves productivity and reduces maintenance cost.

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