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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™
V-to-F Process Receiver & Integrating Totalizer
Rate,
analog square root, batch control, time based on rate |
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Features |
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Standard
Counter |
Square
root readout from analog output of differential pressure
flow transducers. |
-1
mA, 4-20 mA, 0-10 V inputs, or special factory scaling. |
6-digit
resolution. |
Field
scalable for direct readout in engineering units. |
Isolated
5, 10, or 24 Vdc excitation output to power sensors. |
Selectable
"count by" of 10 or 100 with rounding. |
25/s
update rate. |
Peak
value display. |
Green
or red LED 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, and parallel BCD output. |
Certified
to UL 3101-1, CAN/CSA-C22.2, EN 61010-1 (CE Mark). |
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Extended
Counter
All
capabilities of the Standard Counter, plus: |
Custom
curve linearization. |
Total
based on rate and time. |
Batch
control based on rate and total. |
Display
of process time based on rate input. |
Click
to Order V-to-F Process Receiver Totalizer
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Description |
Standard
Counter Version
Rate with Square Root
Extraction
A
Laureate™ meter with the Standard counter main
board and a voltage-to-frequency (V-to-F) signal conditioner
board is able to accurately extract the square root
of analog signals. The display is a full six digits.
The three standard input ranges are 0-1 mA, 4-20 mA
and 0-10 V. Special input ranges are available from
the factory.
One application
of the Standard V-to-F meter is to accurately display
flow rate in engineering units, such as gallons per
minute, from the 4-20 mA signal of a flow transducer
with a linear or squared output.
Extended
Counter Version
Batch
Control with Linearized Total
The
Laureate V-to-F meter with the Extended counter main
board can also totalize the linearized flow rate derived
from the analog rate signal, count up to a preset value,
or down to zero from a preset value for batch control.
The analog input may or may not require linearization.
In addition to rate and total, the grand total of the
batches or the number of batches can also be displayed
by pressing a front panel key.
Use of the Extended V-to-F meter as an up or down-counting
batch controller requires the dual-relay output board
option. One of the relays is dedicated to ON/OFF batch
control. The other relay is available to slow down rate
near the setpoint or to provide another alarm or control
function based on rate or total
One application of display of rate plus total is to
read out kilowatts and kilowatt-hours based on 0-1 mA
from a watt transducer.
Custom
Curve Linearization
The relationship between the analog input and the
value to be displayed can have a linear, square root,
or custom curve relationship. For custom curve linearization,
up to 240 data points can be input into a spreadsheet
or text file by the user. The computer then calculates
nonlinear segments, which are downloaded into the meter
via RS-232. Custom-linearized rates can be totalized
and be used for batch control.
Like the Extended analog DC panel meter, the Extended
V-to-F meter can linearize and display analog inputs
based on a custom curve unrelated to flow, for instance
to read out the volume of an irregularly shaped tank
based on level or pressure, or to linearize a nonlinear
transducer.
Time Based on Rate
The Extended V-to-F meter can display a time inversely
proportional to measured rate, such as the time that
it will take a conveyor to traverse an oven. As the
rate of the conveyor is increased, the displayed baking
time will be decreased.
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| Hardware
Features |
High
Resolution Display |
| Optional,
plug-in 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. In particular, the analog 4-20
mA or 0-10 V analog output will be linearized to the
reading, which may be rate or total. All Laureate
meters meet the NEMA 4X (IP-65) standard from the front
for high pressure washdown when panel mounted. |
The display of rate or total
may be scaled to ±999,999. The two least-significant
digits may be set to display zero with rounding or be
active digits. In addition to a selectable gate time
for rate measurement, an adaptive filter can reduce
variations due to noise while rapidly responding to
actual changes in signal level |
| Principles
of V-to-F Operation |
| The
V-to-F signal conditioner board converts the full-scale
0-1 mA, 4-20 mA or 0-10 V analog signal to a frequency
of 10-110 kHz. This frequency is determined by measuring
period over a selected gate time (from 10 ms to 200
s) and taking the inverse of period. Selecting a short
gate time provides a much higher update rate than conventional
counting-type frequency meters. At the lowest frequency
of 10 kHz and the minimum gate time of 10 ms, the meter
is capable of 25 updates per second.
Scaling to rate in engineering units and totalizing
are done mathematically. Totals are stored in nonvolatile
memory in case of power loss |
Click
to Order V-to-F Process Receiver Totalizer
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Specifications |
| Display |
Excitation
Output |
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Standard
signal levels |
0-1
mA, 4-20 mA, 0-10 V
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5
Vdc |
5
Vdc ±5%, 100 mA max |
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Other
signal levels |
Consult
factory |
10
Vdc |
10
Vdc ±5%, 120 mA max |
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------ |
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24
Vdc |
24
Vdc ±5%, 50 mA max
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Output
isolation |
50
Vdc to meter ground |
Accuracy |
Electrical
Connections |
Span
Tempco |
0.003%
R/°C |
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Zero
Tempco |
0.001
FS/°C |
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Conversion |
Power |
Frequency
Technique |
Inverse
period |
Voltage,
std.
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85-264
Vac and 90-370 Vdc
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Rate |
Gate
time + 30 ms (max) |
Frequency
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DC
or 49-440 Hz
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Gate
Time |
Selectable
10 ms to 199.99 s |
Voltage,
opt. |
8-28
Vac and 9-37 Vdc
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Output
& Display Updates |
Same
as conversion time |
Power
isolation |
Safety-rated
to 250 Vac, meter ground to earth ground,
DC to 60 Hz, 4.2 kVp per High Voltage Test |
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CMR |
130
dB, DC to 60 Hz |
Inputs |
Types |
Differential
or single-ended quadrature |
Max
Pulse Rate |
250
kHz at x1, 125 kHz at x2, 62.5 kHz at x4 |
Transitions
Monitored
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x1,
x2 or x4
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Position
Error |
No
error contributed by meter |
| Environmental |
Operating
Temperature |
0°C
to 55°C |
Storage
Temperature |
-40°C
to 85°C |
Relative
Humidity |
95%
at 40°C, non-condensing |
Protection |
NEMA-4X
(IP-65) when panel mounted |
Click
to Order V-to-F Process Receiver Totalizer
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Typical
Application Examples |
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Flow
from a Differential Pressure Transducer |
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An
ideal application for the Standard Laureate V-to-F
meter: readout of flow based on the 4-20 mA analog
signal from a differential pressure transducer.
Options include dual relays for alarm or control,
isolated analog output to turn the meter into a
transmitter, and RS-232/485 or BCD data communications.
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Up-
or Down-Counting Batch Controller |
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An
ideal application for the Extended Laureate V-to-F
meter: up- or down-counting batch controller. The
dual-relay card is required. One relay is dedicated
to batch control, the other relay is available to
alarm the rate or total. The signal input can be
linear or nonlinear. The display can be toggled
between rate and total. |
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Linearizing
Nonlinear Inputs |
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The Extended
Laureate V-to-F meter can linearize analog signals
for display and alarm using custom curve linearization
with multiple nonlinear segments. As illustrated,
tank level is measured by an ultrasound detector,
which transmits a 4-20 mA signal. This signal is
then converted to a highly accurate volume reading.
The linearized rate readings can also be totalized. |
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Process
Time from an Analog Rate Signal |
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A
unique application of the Extended Laureate V-to-F
meter: displaying process time based on the 4-20
mA or 0-10 V signal from a rate meter. In the above
example, a tachometer transmits the speed of a conveyer
belt through an oven. The meter displays baking
time in the oven using the mathematical relationship
time = distance / speed. |
Click
to Order V-to-F Process Receiver Totalizer
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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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