Laurel Laureate Load Cell & Microvolt Digital Panel Meter

The Laurel Laureate load cell and microvolt meter is a 5-digit panel meter with exceptionally high accuracy and stability for use with low-level signals.

Load cell meter operation provides sensitivity down to ±20 mV full scale for use with 2 mV/V load cells at 10V excitation. Ratiometric operation automatically compensates for changes in excitation. The 5 digit display can be scaled for direct readout in engineering units, such as pounds, kilograms or PSI. Scaling can be via front panel pushbuttons or a computer. Zero may be set from -99,999 to +99,999. Range may be scaled from 0 to ±99,999. Digital scaling and calibration eliminate drift caused by potentiometers in non-microcomputer based meters.

DC microvoltmeter operation provides sensitivity down to ±20 mV full scale with 1 µV resolution for use with 2 mV/V load cell. A display span of 99,999 counts with sensitivity of 0.2 µV per count can be obtained by applying a digital multiplier of five. A moving average digital filter assures quiet readings in electrically noisy environments.

Meter accuracy is 0.01% of full scale ± 2 counts. Custom curve linearization, which is available with the optional extended main board, can extend the working range of load cells. Custom curve linearization also allows greater accuracy to be achieved with lower cost, less linear load cells.

A built-in isolated excitation supply can provide up to 120 mA of current at 10V to power four 350-ohm load cells in parallel. The meter operates in a ratiometric mode to eliminate errors due to supply variations. When excitation sense inputs are used in 6-wire connection, the meter compensates for variation in resistance of the transducer leads, thereby allowing long cable runs.

High read rates at up to 60 or 50 conversions per second while integrating the signal over a full power cycle are provided by Concurrent Slope (US Pat 5,262,780) analog-to-digital conversion. High read rates are ideal for peak or valley capture, real-time computer interface, and control.

Peak and valley values are automatically captured. These may be displayed via a front panel pushbutton command or control signal at the rear connector, or be transmitted as serial data.

Digital filtering is selectable for electrically noisy environments, including a batch averaging filter and an adaptive moving average filter which provides a choice of 8 time constants from 80 ms to 9.6 s. When a significant change in signal level occurs, that filter adapts by briefly switching to the shortest time to follow the change, then reverts back to the selected time constant. In a selectable Auto filter mode, the filter time constant is automatically selected based on detected signal noise.

Auto-tare is standard for weighing applications to subtract the weight of an empty container and may be controlled by an external pushbutton contact closure or a logic signal. Additional capabilities for weighing applications are provided by the Laureate weight & scale meter.

The Laurel Laureate load cell and microvolt meter is designed for system use. Optional plug-in boards for communications and control include Ethernet and other serial communication boards, dual or quad relay boards, and an isolated analog output board. Laureates may be powered from 85-264 Vac or optionally from 12-32 Vac or 10-48 Vdc. The display is available with red or green LEDs. The 1/8 DIN case meets NEMA 4X (IP65) specifications from the front when panel mounted. Any setup functions and front panel keys can be locked out for simplified usage and security. All power and signal connections are via UL / VDE / CSA rated screw clamp plugs.