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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™
A/B Ratio & A/B-1 Draw Meters
With arithmetic functions applicable to rate or total
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Extended
Counter |
| A/B,
A/B-1 (draw), A+B, A-B, AxB arithmetic functions applied
to Channels A & B. |
Applicable
to rate or total. |
| Frequencies
from 0.005 Hz to 1 MHz. |
Independent
scaling for each channel. |
| Inputs
from NPN or PNP proximity switches, contact closures,
digital logic, magnetic pickups down to 12 mV, or AC
inputs up to 250 Vac. |
Update
rates to 25/s. |
| Selectable
"count by" of 10 or 100 with rounding. |
isolated
5, 10 or 24 Vdc excitation supply to power sensors. |
| Green
or red 6-digit LED display |
NEMA
4X, 1/8 DIN case |
| Dual
relay option |
Analog
output option |
| Serial
communication options |
Low
voltage AC & DC power |
| Safety
certified to UL 61010C-1 (UL mark). |
EM
certified to EN 61010-1 (CE mark). |
Click
To Order A/B Ratio Meter
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Description |
The
A/B ratio and A/B-1 draw meters are selectable
operating modes of the Laureate with Extended counter
main board and FR dual-channel signal conditioner
board.
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Ratio
can be used to compare flow rates in two channels,
the RPM of rollers or gears, or the speed of
moving machinery, such as conveyor belts. Ratio
can also be applied to scaled totals to compare
two batches to be mixed. In this application, one
meter is used to monitor the ratio of flow rates,
and a second meter to monitor the resulting batch
totals.
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Draw
is obtained by subtracting 1 from ratio. Draw is
often used to measure the elongation or shrinkage
of material as it passes between rollers, or to
monitor variation in the speed of rollers for
tensioning.
Ratio and
draw are similar, except that 1 is subtracted from
ratio to obtain draw. The frequency of channels A and
B is first measured and is then converted to rate in
engineering units by multiplying it by the appropriate
scale factor for that channel. Either rate can be
displayed. The A/B ratio is then taken mathematically
by the meter, and 1 is subtracted for draw. The result
can be multiplied by a multiple or 10 from 0.0001 to
100000, and the decimal point can be set to display
the result with the desired precision up to six
digits.
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| Fast,
High Resolution Measurement |
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The Laureate
counter determines frequency by timing an integral
number of periods over a programmable gate time. The
inverse period approach allows greater accuracy and
faster update times than conventional meters which count
signal pulses over a specified time interval.
Channel A
accepts pulses from 0.005 Hz to 1 MHz, while Channel B
accepts pulses from 0.005 Hz to 250 kHz. At the minimum
gate time of 10 ms, update rates can be up to 25/second.
Such fast response is ideal for peak capture and for
alarm and control applications. Variations in the
displayed reading can be reduced by selecting a longer
gate time. An adaptive filter can further reduce
variations due to noise while rapidly responding to
actual changes in the signal. |
| Universal
Signal Conditioner |
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The Laureate
dual-channel signal conditioner accepts inputs from
proximity switches with PNP or NPN output, TTL or CMOS
logic, magnetic pickups, contact closures, low-level
outputs from turbine flow meters down to 12 mV , and
high-level AC line inputs up to 250 Vac. Jumper
selections provide optimum operation for different sensor
types and noise conditions.
A built-in
isolated 5, 10, or 24 Vdc excitation supply can power
proximity switches and other sensors, and eliminate the
need for an external power supply.
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| Other
Features & Options |
| A
built-in isolated 5, 10, or 24 Vdc excitation supply
can power the transducer and eliminate the need for
an external power supply. Plug-in isolated
analog output, dual-setpoint controller, and RS-232/485
communications, boards can upgrade the Laureate ratio
meter from stand-alone monitor to system interface and
control. In particular, the meter can provide an isolated
4-20 mA output signal scaled to the display. The 1/8
DIN case of Laureate meters and counters meets NEMA
4X (IP-65) standards from the front for high pressure
wash-down when panel mounted. |
Click
To Order A/B Ratio Meter
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Specifications |
| Inputs |
Update
Rate |
| Types
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AC,
pulses from NPN, PNP transistors, contact closures,
magnetic pickups |
Frequency
Technique |
Inverse
period
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Signal
Ground |
Common
ground for channels A & B |
Conversion
Time |
Gate
time + 30 ms+ 0-2 signal periods |
Channel
A Frequency |
0.005
Hz to 1 MHz |
Gate
Time |
Selectable
10 ms to 199.99 s
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Channel
B Frequency |
0.005
Hz to 250 kHz |
Time
Before Zero Output |
Selectable
10 ms to 199.99 s |
Minimum
Signal
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Nine
ranges from (-12 to +12 mV) to (+1.25 to +2.1V).
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Accuracy |
Maximum
Signal
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250
Vac
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Time
Base |
Crystal
calibrated to ±2 ppm
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Noise
Filter |
1
MHz, 30 kHz, 250 Hz (selectable)
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Span
Tempco
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±1
ppm/°C (typ) |
Contact
Debounce |
0,
3, 50 ms (selectable) |
Long-term
Drift |
±5
ppm/year |
Display |
Excitation
Output |
Readout |
6
LED digits, 7-segment, 14.2 mm (.56"), red
or green LED. |
5
Vdc |
5
Vdc ±5%, 100 mA max |
Zero
Adjust |
-999999
to +999999 |
10
Vdc |
10
Vdc ±5%, 120 mA max |
Range |
-999999
to +999999, XXXXEX scientific notation beyond 999999 |
24
Vdc |
24
Vdc ±5%, 50 mA max |
Indicators |
4
red LED lamps |
Output
isolation |
50
Vdc to meter ground |
Analog
Output (optional) |
Dual
Contact Relay Outputs (optional) |
Output
levels
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0-10V,
0-20 mA, 4-20 mA (jumper selectable)
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Relay
Type
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Form
C
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Compliance
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2
mA at 10V (5 kOhm load), 12V at 20 mA (0-60 ohm load) |
Load
Rating
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120
mA at 130 Vac or 170 Vdc, 28 ohms series resistance.
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Scaling
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Zero
and full scale adjustable from -99999 to +99999
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Isolation |
250V
rms working, 2.3 kV rms per 1 min test |
Resolution |
12
bits (0.025% of full scale)
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Isolation |
250V
rms working, 2.3 kV rms per 1 min test |
Dual
Solid State Relay Outputs
(optional) |
Serial
Data I/O (optional) |
Relay
Type
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SPST,
normally open, Form A |
Board
Selections |
RS232,
RS485, Modbus RS485 |
Protocols |
Modbus
RTU, Modbus ASCII, simpler Laurel ASCII |
Load
Rating |
120
mA at 130 Vac or 170 Vdc, 28 ohms series resistance |
Data
Rates
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300
to 19200 bps
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Digital
Addresses
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247
(Modbus), 31 (Laurel ASCII), |
Isolation |
250V
rms working, 2.3 kV rms per 1 min test |
Isolation |
250V
rms working, 2.3 kV rms per 1 min test |
Environmental |
Signal
Connections |
Operating
Temperature |
0°C
to 60°C
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Storage
Temperature |
-40°C
to 85°C
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Relative
Humidity
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95%
at 40°C, non-condensing |
Protection |
NEMA-4X
(IP-65) when panel mounted |
Click
To Order A/B Ratio Meter
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| Applications |
| Controlling
the Mixing Ratio of Two Fluids |
Comparing
Fluid Inflow & Outflow |
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Displaying
and alarming the input flow rate ratio of two fluids
(gas or liquid) allows these to be mixed in a predetermined
ratio in continuous processes. The sensing element
is normally a turbine flowmeter, which outputs pulses
at a frequency proportional to flow rate. The A/B
ratio can also be displayed for totalized rate (or
delivered volume). |
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The
ratio of the inflow and outflow rates of a tank
is a measure of the relative filling or emptying
rate. The same meter can also be programmed to display
the net inflow or outflow rate in flow units, or
to display totalized inflow our outflow in volume
units. Any of these parameters can be alarmed using
the dual relay board and be transmitted via 4-20
mA, RS-232 or RS-485. |
| Controlling
Coating Thickness on a Film |
Synchronizing
Two Conveyor Lines |
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In
this application, Channel A measures the rate at
which a coating material is applied, as measured
by a flow meter, while Channel B measures the speed
of the film based on pulses from a proximity switch.
Displaying and alarming the A/B ratio assures that
an even thickness of coating material is applied
as the speed of the film is varies. |
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The
dual-channel Laureate counter can measure the speed
of conveyor lines by using the output of proximity
switches which sense gear teeth or spokes of rotating
drive wheels. Displaying the speed ratio of two
lines allows line speeds to be adjusted so that
material arrives at work stations when needed.
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Measuring
Draw for Elongation |
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| Draw
(Ch A / Ch B - 1) can be used to display the elongation
of films compressed between rollers, the shrinkage
films, and the RPM difference of rollers whose speed
is varied to maintain tension. The six-digit resolution
of the Laureate dual channel counter / rate meter
is ideal for comparison of rates that are close
to each other. |
Click
To Order A/B Ratio 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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