The Fisher™ FIELDVUE™ DPC2K digital process controller (DPC2K) has been announced by Emerson. The DPC2K can be retrofitted to Fisher Wizard pneumatic controllers, and to pneumatic controllers from other manufacturers. The result is greatly improved closed-loop control and reliability, significantly reduced maintenance, improved safety, and superior environmental compliance. It also provides numerous connectivity options, enabling remote setpoints, remote access for configuration, monitoring, and other features.
Pneumatic controllers have served industry well for decades to regulate control valve actions, but they have many limitations. Closed loop control is sluggish and not precise, with significant deviations from setpoint common, and degraded performance over time as their mechanical components wear out. This wear and tear negatively impact reliability, with excessive maintenance required. All interactions with pneumatic controllers must be performed locally at the control valve, creating safety issues by exposing personnel to often hazardous plant environments.
The DPC2K addresses these and other issues, and it can be retrofitted as a direct replacement for the pneumatic controllers installed on most valves, regardless of manufacturer. Closed loop control is greatly improved with configurable loop types, over 150 units of supported measure, 20 times-per-second (50 milliseconds) scan and update rates, configurable dead band, anti-reset windup, dynamic reset limiting, and other features. These features work together to keep the process variable—typically pressure, flow, level or temperature—close to setpoint, along with greatly improved recovery from saturated conditions.
The DPC2K is designed to maintain its high level of performance for years with no required maintenance, and when maintenance is required, it is easily performed using modular replacement components. Another important advantage from this upgrade is the ability to easily interact with the DPC2K locally or remotely. Local interactions are performed via its menu-driven LCD and six-button user interface, with four buttons used for navigation and two for operator input.
The DPC2K has inputs, outputs, and intelligence to perform local closed-loop digital control using the proportional–integral–derivative (PID) controller. It can accept a 4-20mA input from a two-wire or four-wire instrument, typically the process variable (PV). For pressure control applications, an optional pressure sensor can be used to provide the PV.
Fisher LoopConnect software provides the most comprehensive remote access, including configuration and monitoring, networked or direct Ethernet connection, and alerts for troubleshooting. Options include integral, sealed gauge pressure sensor with 0-30, 0-100, 0-300, 0-600, or 0-1500 pounds-per-square-inch range; and pneumatic output with low bleed of less than 3.0 standard cubic feet per hour.
Because the DPC2K is configurable, the same base model can be used in a variety of applications, including but not limited to pressure, flow, level, temperature, percentage, volume, and rate control. The DPC2K is rated for use in Class 1 Division 1 or Zone 1 hazardous areas, and it has an operating temperature range of -40-80 degrees Celsius. Inputs of 9-28 volts direct current are accommodated, with a typical power draw of only 1 watt.
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