Laurel Electronics Laureate Digital Panel Meter for Load Cell & Microvolt Input - Manual

LAUREL ELECTRONICS INC., 3183-G Airway Ave., Costa Mesa, CA 92626, USA • Tel 714-434-6131 • www.laurels.com 1
LAUREL
ELECTRONICS, INC.
Laureate™ Digital Panel Meter
for Load Cell & Microvolt Input
Features
• 20, 50, 100, 250 & 500 mV ranges
• Span adjust from 0 to ±99,999, zero adjust from -99,999 to +99,999
• Selectable fixed right-hand zero with rounding
• Isolated 10 Vdc supply to power up to four 350-ohm load cells in parallel
• 4- or 6-wire hookup to avoid lead resistance effects
• 1 Gohm input impedance
• Up to 60 conversions per second
• Peak or valley display
• Auto-tare with tare value stored in memory
• Universal AC power, 85-264 Vac
• 1/8 DIN case sealed to NEMA-4X from front panel
• Optional serial I/O: Ethernet, USB, RS232, RS485, Ethernet-to-RS485 converter
• Optional relay output: dual or quad relays, contact or solid state
• Optional isolated analog output: 4-20 mA, 0-20 mA, 0-10V, -10 to +10V
• Optional low voltage power: 10-48 Vdc or 12-32 Vac
Description
The Laureate ™ load cell & microvolt meter is a high-
sensitivity monitor and controller for use with load cells, strain
gauges and microvolt input signals where high accuracy and
stability are required.
• DC microvoltmeter operation provides sensitivity down
to ±20 mV full scale with 1 µV resolution. 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.
• Load cell operation allows six-wire hookup and scaling for
direct readout in engineering units, such as pounds, kilograms
or PSI. Scaling can be via front panel pushbuttons or a com-
puter. 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.
Meter accuracy is 0.01% of full scale ± 2 counts with an ideal
load cell. Custom curve linearization, which is available with the
optional Extended main board, can extend the working range of
real-world load cells. Custom curve linearization also allows high
accuracy to be achieved with lower cost, less linear load cells.
A built-in isolated 10 Vdc 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 to allow 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 conver-
sion. 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 aver-
age 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 constant to
follow the change, then reverts back to the selected time con-
stant. In a selectable Auto filter mode, the filter time constant is
automatically selected based on detected signal noise.
Easy scale and offset are provided by Laureate DC, process
and load cell meters by either of two selectable methods:
• With the coordinate reading method, the meter reads the
high and low signal values, and the user enters the desired
high and low reading values. The meter then calculates the
span multiplier and offset. This method is ideal if an external
calibration reference is available.
• With the manual coordinate method, the user enters the
high and low input values in Volts plus the desired high and
low reading values. This method is suitable if no external
calibration reference is available.
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.
Designed for system use. Optional plug-in boards 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. A built-
in isolated 5, 10, or 24 Vdc excitation supply can power trans-
ducers and eliminate the need for an external power supply. All
power and signal connections are via UL / VDE / CSA rated
screw clamp plugs.