Fisher® DLC3010 HART® Digital Level Controller
DLC3010 digital level controllers are used with level sensors to measure liquid level, the level of interface between two liquids, or liquid specific gravity (density). They are communicating, microprocessor-based sensing instruments. In addition to the normal function of providing a 4 to 20 mA current signal, DLC3010 digital level controllers, using the HART communications protocol, give easy access to information critical to process operation.
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- Simplified Setup and Calibration—For quick analog transmitter replacement (4-20mA out only), the instrument may be configured with default sensor data, zero Level Offset, differential process SG, and zero/span procedure only. For full compensation and diagnostic capabilities, complete sensor data entry and calibration is recommended.
Through the use of an electronic Setup Wizard, digital level controller start-up is straightforward and fast. Level and temperature alarms, specific gravity tables, calibration trim and trending are readily configurable. DLC3000 Series digital level controllers also support re-ranging without a fluid reference.
- Responsive to Small Process Changes—Accurate, high-gain analog-to-digital conversion enables measurement of small changes in the process variable. This allows DLC3000 Series digital level controllers to be used in difficult liquid level, interface, or density applications. In addition, an adjustable input filter and output damping help to attenuate displacer-induced ripple in the output signal due to liquid turbulence.
- Reduced Temperature Effects—An internal temperature sensor enables consistent performance of the digital level controller despite ambient temperature changes. With a temperature input signal, either via HART protocol or an RTD connected to the instrument, the digital level controller can also automatically compensate for specific gravity changes due to temperature. A user-supplied table of up to ten linear segments may be entered to implement this feature. (An sample water/steam table is provided in the FIELDVUE DLC3000 Series Digital Level Controls instruction manual, Form 5631). The measured torque tube rate may be manually pre-compensated for a target process temperature using the data available in the DLC3000 Device Description (DD).
- Additional Compensation—The instrument measurement algorithm corrects for the small motion of the displacer as buoyancy changes, allowing it to calculate the true cage or vessel level. This provides additional accuracy on the shorter displacers.
- Rugged Construction—Mechanical safeguards designed into the digital level controller help it to withstand physical abuse often incurred during installation or in transport, without compromising performance. The fully encapsulated printed wiring boards resist the effects of vibration, temperature, and corrosive atmospheres. The lever assembly is pinned at the neutral position when the coupling access door is open, providing shipping stabilization for a separate transmitter purchase. Locking set screws are provided for covers and the access door handle.
- Easy Maintenance—Field wiring connections are in a compartment separated from the electronics. This protects the electronics from any moisture brought into the housing by the field wiring. This also eases installation and maintenance. The digital level controller does not have to be removed to facilitate troubleshooting or service. Modular construction allows servicing in the field. However, if it is necessary to remove the digital level controller for in-shop maintenance and calibration, field wiring does not need to be disconnected.
- Alarm Jumper—DLC3000 Series digital level controllers include self-diagnostics that detect an error (e.g. electronics failure) that would render the process variable measurement inaccurate. The instrument can also be configured to indicate a process variable high or low alarm. When a process variable alarm or an error is detected the analog output signal is driven either above or below the normal 4 to 20 mA range, depending on the user-selectable position of the alarm jumper. The unit ships from the factory with the jumper in the high position.
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