Laurel Electronics LTE: Ethernet & 4-20 mA Output Transmitter for Resistance in Ohms - Manual

LAUREL ELECTRONICS INC., 3183-G Airway Ave., Costa Mesa, CA 92626, USA • Tel 714-434-6131 • www.laurels.com 1
LAUREL
ELECTRONICS, INC.
Ethernet & 4-20 mA Output Transmitter
for Resistance in Ohms
Features
• Ethernet Serial Data I/O, Modbus TCP or Laurel ASCII protocol
• 4-20 mA or 0-10V transmitter output, 16 bits, jumper selectable, isolated
• Dual 120 mA solid state relays for alarm or control, isolated
• Five precalibrated resistance input ranges from 20.000 Ω to 200.00 kΩ
• Fixed 2.0000 MΩ range available as a factory special
• 1 mΩ resolution on 20 Ω scale
• Custom curve linearization for varying resistance transducers
• 2, 3 or 4-wire connection with lead resistance compensation
• DIN rail mount housing only 22.5 mm wide, detachable screw-clamp connectors
• Universal 85-264 Vac / 90-300 Vdc or 10-48 Vdc / 12-32 Vac power
• Power over Ethernet (PoE) jumper selectable with 10-48 Vdc supply
Description
The Laureate Resistance Transmitter is factory calibrated for
five jumper selectable resistance ranges from 20 Ω to 200 kΩ.
Accuracy is an exceptional 0.01% of full scale 2 counts. Resolu-
tion is one part in 20,000. In the 20 Ω range, resolution is 1 mΩ,
making the transmitter suitable for contact resistance and
conductance measurements.
Transmitter connections can be via 2, 3 or 4 wires. With 4-wire
hookup, 2 wires are used for excitation and two separate wires
are used to sense the voltage across the resistance to be
measured, thereby eliminating any lead resistance effects. With
3-wire hookup, the transmitter senses the combined voltage drop
across the RTD plus two excitation leads. It also senses the
voltage drop across one excitation lead, and then subtracts twice
this voltage from the combined total. This technique effectively
subtracts the lead resistance if the excitation leads are the same.
All resistance ranges are digitally calibrated at the factory, with
calibration factors stored in EEPROM on the signal conditioner
board. This allows ranges and signal conditioner boards to be
changed in the field without recalibrating the transmitter. If
desired, the transmitter can easily be calibrated using external
standards plus scale and offset in software.
Fast read rate at up to 50 or 60 conversions per second while
integrating the signal over a full power line cycle is provided by
Concurrent Slope (Pat 5,262,780) analog-to-digital conversion.
High read rate is ideal for peak or valley capture and for real-time
computer interface and control.
Open sensor indication is standard and may be set up to indi-
cate either upscale or downscale. Excitation is provided by the
transmitter.
Custom curve linearization, available with the Extended
version, makes this transmitter ideal for use with transducers
whose output is a changing resistance.
Standard features of Laureate LTE transmitters include:
• Ethernet I/O, isolated. Supported protocols are Modbus
RTU and ASCII (tunneled via Modbus TCP) and Laurel ASCII.
The latter is simpler than the Modbus protocol and is recom-
mended when all devices are Laureates. Note that RS232 or
RS485 data I/O in lieu of Ethernet is provided by our LT Series
transmitters.
• 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.
• Dual solid state relays, isolated. Available for local alarm
or control. Rated 120 mA at 130 Vac or 180 Vdc.
• Universal 85-264 Vac power. Low-voltage 10-48 Vdc or
12-32 Vac power is optional.
Discovery and configuration of Laureate Ethernet Nodes is
easily achieved with Laurel's Node Manager Software, and the
discovered transmitters can then be programmed using Laurel's
Instrument Setup Software. Both softwares run on a PC under
MS Windows and can be downloaded at no charge.