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Laurel Electronics provides
digital panel meters / controllers, totalizers, counters, loop-powered meters,
temperature meters, for all types of transducers or process indication &
control. |
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Laureate™ Load Cell &
Microvolt Panel Meter
10 mV - 500 mV
full-scale ranges, 4- or 6-wire connection |
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Features |
20,
50, 100, 250 & 500 mV ranges. |
5-digit
resolution with span from 0 to ± 99,999 |
Zero
from -99,999 to +99,999 |
Isolated
10 Vdc supply to power up to four 350 ohm load cells. |
Selectable
fixed zero or active least significant digit. |
4-
or 6-wire hookup. |
Ratiometric
operation cancels variations in excitation supply. |
Up
to 60 conversions per second. |
Peak
value display standard. |
Auto-tare
with tare value stored in memory |
AC
or DC powered. |
Green
or red display. |
NEMA
4X (IP-65) front panel, 1/8 DIN case. |
Optional
dual relays, 4-20 mA & 0-10 V analog output, RS-232/485
I/O, parallel BCD output, and low voltage power. |
Certified
to UL 3101-1, CAN/CSA-C22.2, EN 61010-1 (CE Mark). |
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Click
to Order Load Cell Panel Meter
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Description |
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The
Laureate™ load cell and microvoltmeter 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.
Usage
as a DC microvoltmeter provides sensitivity down to
20 mV full scale with 1 µV resolution. With a digital
multiplier of five, 99,999 counts can be displayed with
a sensitivity of 0.2 µV per count. A moving average
filter with a time constant of 1.2 sec or greater should
then be selected.
Usage
as a load cell meter 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 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. |
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| Built-in
Excitation |
Fast
Read Rate plus Peak Capture |
Selectable
Signal Filtering |
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An
isolated 10 Vdc excitation supply can provide up to
120 mA of current to power up to 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. |
All
Laureate meters use Concurrent Slope (Pat 5,262,780)
analog-to-digital conversion, which allows up to 60
conversions per second, while integrating the signal
over a full power cycle. High read rate is ideal for
peak value capture and for real-time computer interface
and control. Peak
capture is standard |
The
displayed readings and the data outputs can be separately
selected to be either unfiltered or filtered.
An
unfiltered selection
updates after each conversion for fastest response,
up to 60/sec, while integrating the input signal over
a full power cycle. Fast read rate provides true peak
readings and aids in control applications.
A batch average filter selection averages
each 16 conversions for an update every 1/4 sec.
An adaptive moving average filter selection
provides a choice of 8 time constants from 80 ms to
9.6 s. When a significant change in signal level occurs,
the filter adapts by briefly switching to the shortest
time to follow the change, then reverts back to its
selected time constant. Another choice is Auto, which
provides an automatic time constant selection based
on the signal noise characteristics. |
| Easy
Scaling |
Auto-tare
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Other
Features & Options |
| All
Laureate DC, process and load cell meters allow easy
setting of scale and offset by either of two methods.
With
the coordinate reading method,
the meter reads the high and low signal values, and
the user enters the desired high an 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 an no external calibration reference
is available. |
For
weighing applications, auto-tare is standard. Auto-tare
can set the displayed value to zero to subtract the
weight of an empty container. Auto-tare may be controlled
by an external pushbutton contact closure or logic signal
through an input on the power supply connector. The
tare value is stored in memory. Additional
capabilities for weighing applications are provided
by the Laureate weight / scale meter, as described in
a separate web page.
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Plug-in
isolated analog output, dual setpoint controller and
RS-232/485 commu- nications or BCD output boards can
upgrade the Laureate from a stand-alone monitor to system
interface and control. All Laureates
meet NEMA 4X (IP-65) standards for high pressure washdown
when panel mounted. All connections are via safety-rated
screw-terminal connectors. |
Click
to Order Load Cell Panel Meter
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Specifications |
| DC
Microvoltmeter Inputs |
Input
Range
mV |
Resolution |
Error
at 25°C |
| ±20.000 |
1.0
µV |
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| ±50.000 |
2.5
µV |
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| ±100.00 |
5.0
µV |
0.01%
FS |
| ±250.00 |
12.5
µV |
±1
count |
| ±500.00 |
25
µV |
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| Load
Cell Inputs |
Full-Scale
Input, mV |
Zero
Adjust |
Span
Adjust |
Error
at 25°C |
| ±20.000 |
-99,999
to
+99,999 |
0
to
±99,999 |
0.01%
FS
±1 count |
| ±50.000 |
| ±100.00 |
| ±250.00 |
| ±500.00 |
| DC
Microvolts & Load Cell |
Accuracy |
Noise
Rejection |
Span
Tempco |
0.0015%
of reading/°C
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CMR,
DC to 60 Hz
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130
dB |
Zero
Tempco |
0.1
µV/°C |
NMR
at 50/60 Hz |
90
dB with min filtering |
A-to-D
Conversion |
Display |
Technique |
Concurrent
Slope™ (Pat 5,262,780) |
Readout |
5
digits, 7-segment, 14.2 mm (.56") |
A-to-D
Rate |
60/s
at 60 Hz, 50/s at 50 Hz |
Color |
Red
or green LED |
Output
Update |
56/s
at 60 Hz, 47/s at 50 Hz |
Range |
-99999
to +99999 or -99990 to +99990 (count by 10 with
rounding) |
Display
Update |
3.5/s
at 60 Hz, 3/s at 50 Hz |
Indicators |
Minus
sign, 2 red LED lamps |
Power |
Excitation
Output |
Voltage,
std |
85-264
Vac and 90-370 Vdc |
5
Vdc |
5
Vdc ±5%, 100 mA max |
Voltage,
opt |
8-28
Vac and 9-37 Vdc |
10
Vdc |
10
Vdc ±5%, 120 mA max |
Frequency |
DC
or 49-440 Hz |
24
Vdc |
24
Vdc ±5%, 50 mA max |
Power
isolation |
Safety-rated
to 250 Vac, meter ground to earth ground,
DC to 60 Hz, 4.2 kVp per High Voltage Test |
Output
isolation |
50
Vdc to meter ground |
Environmental |
Operating
Temperature |
0°C
to 55°C |
Storage
Temperature |
-40°C
to 85°C |
Relative
HumidityProtection |
NEMA-4X
(IP-65) when panel mounted |
Click
to Order Load Cell Panel Meter
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Load
Cell Meter Connections |
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In
4-wire connection, the
excitation and sense lines are tied together. The meter
can make ratiometric corrections for supply voltage
variations, but not compensate for variations in lead
resistance. This connection is often used with short
cable runs. |
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In
6-wire connection, the
sense lines are separate from the excitation lines,
thereby eliminating effects due to variations in lead
resistance. This allows long cable runs in outdoor environments
with temperature extremes. |
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For
large scales, up to four
350 ohm load cells can be powered by a single Laureate,
whose excitation output is rated 120 mA at 10 V. The
excitation and sense points of the four bridges are
connected in parallel through a summing box.
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Sample
Load Cell Meter Applications |
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Auto-Tare
To read
the net weight of an object, the empty container is
first weighed, and an external button is pushed to zero
out the display. The meter will then read net weight
when an object is added to the empty container. The
tare value is stored in memory for subsequent readings.
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Determining
Volume Using Load Cells
An easy
way to determine volume of an irregularly shaped tank
with no need for linearizing is to weigh the tank using
load cells. The meter will automatic- ally tare out
the weight of the empty tank and then scale the load
cell signals to units of volume, such as gallons.
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Peak
Capture for Testing the Tensile Strength of Wire
Peak readings
are automatically captured at rates up to 60 per second,
while the display updates at a legible 3.5 per second.
The peak reading can be recalled at the push of a button
or be always displayed. It can also be transmitted to
a computer via RS-232 or RS-485. |
Click
to Order Load Cell Panel Meter
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FLW,
Inc - 3505
Cadillac Ave - Bldg E - Costa Mesa, CA. - 92626 - USA - Ph (714) 751 -
7512 - Fax (714) 751 - 0213
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