Laurel Electronics LT Ethernet 4-20 User Manual

LAUREL

ELECTRONICS, INC.

Ethernet & 4-20 mA Output Transmitter

Features

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Two independently field-scalable pulse input channels from 0.005 Hz to 1 MHz

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Inputs from NPN or PNP proximity switches, contact closures, digital logic,
magnetic pickups down to 12 mV, or AC inputs up to 250 Vac

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DIN rail mount housing only 22.5 mm wide, detachable screw-clamp connectors

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4-20 mA or 0-10V transmitter output, jumper selectable, isolated

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Analog output resolution 0.0015% of span (16 bits), accuracy ±0.02% of span

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RS232 or RS485 serial data output, half or full duplex, isolated

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Modbus RTU, Modbus ASCII or Laurel ASCII protocol

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5V, 10V or 24V dc transducer excitation output, isolated

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Dual solid state relays for alarm or control, isolated

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Universal AC power, 85-264 Vac, or low voltage power, 10-48 Vdc or 12-32 Vac

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Extended main board for simultaneous rate and total, custom curve linearization,

Description

The Laureate transmitter for frequency, rate or period accepts

two independently scalable input channels from a wide range of
pulse sources, such as NPN or PNP proximity switches, contact
closures, digital logic, magnetic pickups down to 12 mV, or AC
voltages to 250 Vac. Input frequencies can range from 0.005 Hz
to 1 MHz. The transmitter output can be selected as 4-20 mA,
0-20 mA or 0-10V, and is isolated to avoid ground loops. Appli­cations include AC line frequency, RPM or speed from proximity
switch inputs, and flow from turbine flow meter inputs.

With a Standard Main Board, the transmitter output can be
scaled to track frequency in Hz, rate in engineering units (such as
gallons per minute), or period (inverse of frequency). Square root
extraction is standard.

With an Extended Main Board, the transmitter output can track
rate or totalized rate (such as gallons) whether the transducer
output is linear, requires square root extraction, or requires
custom curve linearization. The latter can be provided by a cur­vilinear spline fit with up to 180 data points. The transmitter can
also count up to a preset total or down from a preset total to zero.
Such applications typically make use of optional dual solid state
relays. External reset of totals is via a special three-position
screw terminal connector. The two input channels A & B can also
be combined arithmetically to provide an analog transmitter out­put that tracks A+B (e.g., sum of two flows), A-B (e.g., difference
of two flows), AxB (e.g., horsepower as product of force and
RPM), A/B (ratio of two flow), and A/B-1 (draw or relative elon­gation of material between rollers).

Exceptional accuracy and stability in frequency measurement
are achieved by taking the inverse of period measured with a
calibrated quartz crystal time base. This results in extremely
accurate and stable 6-digit internal readings (±999,999 counts),
which are then processed in software. The analog output is
generated by an ultra-linear 16-bit (65,536 step) digital-to-analog
converter (DAC).

arithmetic functions A+B, A-B, AxB, A/B, A/B-1 (optional)

for Frequency, Rate or Period Input

Standard features of Laureate transmitters include:

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4-20 mA, 0-20 mA or 0-10V analog transmitter output,
isolated, jumper-selectable and user scalable. All selections
provide 16-bit (0.0015%) resolution of output span and 0.02%
output accuracy of a reading from -99,999 to +99,999 counts
that is also transmitted digitally. Output isolation from signal
and power grounds eliminates potential ground loop problems.
The supply can drive 20 mA into a 500 ohm (or lower) load for
10V compliance, or 10V into a 5K ohm (or higher) load for 2
mA compliance.

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Serial communications output, isolated. User selectable
RS232 or RS485, half or full duplex. Three protocols are user
selectable: Modbus RTU, Modbus ASCII, or Laurel ASCII.
Modbus operation is fully compliant with Modbus Over Serial
Line Specification V1.0 (2002). The Laurel ASCII protocol
allows up to 31 Laureate devices to be addressed on the
same RS485 data line. It is simpler than the Modbus protocol
and is recommended when all devices are Laureates.

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Dual solid state relays, isolated. Available for local alarm or
control. Rated 120 mA at 130 Vac or 170 Vdc.

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Transducer excitation output, isolated. User selectable
5V@100 mA, 10V@120 mA or 24V@50 mA.

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Universal 85-264 Vac power. Low-voltage 10-48 Vdc or
12-32 Vac power is optional.

Easy Transmitter programming is via Laurel's Instrument
Setup Software, which runs on a PC under MS Windows. This
software can be downloaded from our website at no charge. The
required transmitter-to-PC interface cable is available from Laurel
(P/N CBL04).

LAUREL

ELECTRONICS INC., 3183-G Airway Ave., Costa Mesa, CA 92626, USA • Tel [phone] • www.laurels.com 1

Specifications

Pulse Input

Signal Types
Grounding
Channel A Frequency
Channel B Frequency
Minimum Signal
Maximum Signal
Noise Filter
Contact Debounce
Time Base Accuracy

Analog Output (standard)

Output Levels
Compliance, 4-20 mA
Compliance, 0-10V
Output Resolution
Output Accuracy
Output Update Rate
Output Isolation

Serial Communications (standard)

Signal Types
Data Rates
Output Isolation
Serial Protocols
Modbus Modes
Modbus Compliance
Digital Addressing

Dual Relay Output (standard)

AC, pulses from NPN, PNP transistors, contact closures, magnetic pickups.
Common ground for channels A & B

0.005 Hz to 1 MHz

0.005 Hz to 250 kHz
Nine ranges from (-12 to +12 mV) to (+1.25 to +2.1V)
250 Vac
1 MHz, 30 kHz, 250 Hz (selectable)
0, 3, 50 ms (selectable)
Quartz crystal calibrated to ±2 ppm

4-20 mA and 0-10 Vdc (selectable)
10V ( 0-500Ω load )
2 mA ( 5 kΩ load )
16 bits (65,536 steps)

0.02% of output span
Programmed gate time + 30 ms + 0-2 signal periods
250V rms working, 2.3 kV rms per 1 minute test

RS232 or RS485 (half or full duplex)
300, 600, 1200, 2400, 4800, 9600, 19200 baud
250V rms working, 2.3 kV rms per 1 min test
Modbus RTU, Modbus ASCII, Laurel ASCII
RTU or ASCII
Modbus over Serial Line Specification V1.0 (2002)
247 Modbus addresses. Up to 32 devices on an RS485 line with no repeater

Relay Type
Load Rating

Sensor Excitation Output (standard)

Output Levels
Output Isolation

Power Input

Standard Power
Low Power Option
Power Frequency
Power Isolation
Power Consumption

Mechanical

Dimensions
Mounting
Electrical Connections

Environmental

Operating Temperature
Storage Temperature
Relative Humidity
Cooling Required

Two solid state relays, SPST, normally open, Form A
120 mA at 140 Vac or 180 Vdc

5V@100 mA, 10V@120 mA, 24V@50 mA (jumper selectable)
50V from signal ground

85-264 Vac or 90-300 Vdc (DC operation not UL approved)
10-48 Vdc or 12-32 Vac
DC or 47-63 Hz
250V rms working, 2.3 kV rms per 1 min test
2W typical, 3W with max excitation output

129 x 104 x 22.5 mm case
35 mm rail per DIN EN 50022
Plug-in screw-clamp connectors

0°C to 55°C

-40°C to 85°C
95% at 40°C, non-condensing
Mount transmitters with ventilation holes at top and bottom.
Leave 6 mm (1/4") between transmitters, or force air with a fan.

LAUREL

ELECTRONICS INC., 3183-G Airway Ave., Costa Mesa, CA 92626, USA • Tel [phone] • www.laurels.com 2

Pinout

Mechanical

Application Examples of Frequency / Rate Meters & Transmitters

AC Line Frequency

Laureate frequency meters and transmitters accept line voltages
up to 250 Vac and output line frequency to 6-digit accuracy
(50.0000 or 60.0000) in a few line cycles. Fast low frequency
response is achieved by timing the period and taking its inverse.

RPM and Speed

Laureate frequency meters and transmitters can sense low-level
signals from magnetic pickups or the NPN or PNP transistor
output of active sensors. These can be powered directly by the
meter or transmitter. Output in RPM or units of speed is
achieved by mathematical scaling.

LAUREL

ELECTRONICS INC., 3183-G Airway Ave., Costa Mesa, CA 92626, USA • Tel [phone] • www.laurels.com 3

Flow Rate and Simultaneous Total

Laureate frequency meters and transmitters are compatible
with all flow meters which generate pulses at a frequency
proportional to flow rate. The Extended version can display
scaled rate or total for the same input at the push of a button,
and alarm from both the rate and total.

Combining Two Rates

Extended Laureate frequency meters and transmitters offer
A+B, A-B and A/B arithmetic functions. A+B allows two input
flows to be summed for total flow, while A-B allows outflow to
be subtracted from inflow for net flow. Flow ratios aid in the
proper mixing of ingredients.

Custom Curve Linearization

Extended Laureate frequency meters and transmitters can
linearize the output turbine flow meters, which tend to be
nonlinear on the low end. Linearizing improves their dynamic
range and accuracy.

Ordering Guide

Create a model a model number in this format: LT60FR, CBL04

Transmitter Type LT Laureate 4-20 mA Transmitter

Main Board

Power 0 Isolated 85-264 Vac

Input Type FR Dual-Channel Frequency

Accessories CBL04 RS-232 cable, TA to computer or USB adapter

6 Standard Main Board
8 Extended Main Board

With Standard Main Board: Scalable to ±999,999 for frequency, rate, square root of
rate, up or down total, period, A-to-B time interval.

With Extended Main Board: Above, plus rate and total simultaneously, ratio (A/B),
draw (A/B-1), other arithmetic functions (AxB, A+B, A-B), phase angle, stopwatch,
up/down counting, batching operation, linearization of nonlinear inputs.

1 Isolated 12-32 Vac or 10-48 Vdc

CBL02 USB to RS-232 cable adapter

LAUREL

ELECTRONICS INC., 3183-G Airway Ave., Costa Mesa, CA 92626, USA • Tel [phone] • www.laurels.com 4