Modbus & Serial Output Transmitter
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Standard Features
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Description The Laureate Modbus & serial output, load cell or microvolt input transmitter is designed for use with load cells, strain gauges and microvolt input signals where exceptional sensitivity and stability are required. A most sensitive full-scale input range ±20 mV can be scaled internally to ±99,999 counts. A built-in, isolated, 10V, 120 mA excitation supply can power up to four 350-ohm load cells in parallel. Load cell connection can be via 4 or 6 wires. With 4-wire load connection, the transmitter operates in a ratiometric mode to eliminate errors due to supply variations. With 6-wire load connection, it also compensates for variation in resistance of the transducer leads, thereby allowing long cable runs. Fast read rate at up to 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. Digital signal filtering modes are selectable for stable readings in electrically noisy environments. The internal digital readings and analog output can be separately selected to be either unfiltered or filtered.
LTM Series serial output transmitters send data via an isolated serial port, which is user configurable for RS232 or RS485 and full or half duplex operation. 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. It also allows use of Laurel Datalogging Software. Standard features of Laureate transmitters include:
Easy Transmitter programming is via Laurel's Instrument Setup Software, which runs on a PC under MS Windows. This software can be downloaded from this website at no charge. The required transmitter-to-PC interface cable is available from Laurel (P/N CBL04). |
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Specifications
Laureate Modbus & Serial I/O Transmitter
for Load Cell or Microvolt Input
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Analog Input |
Range | Resolution | Input Ohms |
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Load Cell |
±20.000 mV ±50.0000 mV ±100.00 mV ±250.00 mV ±500.00 mV |
-99,999 to +99,999 zero adjust. 0 to ±99,999 span adjust. |
1 Gohm |
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Microvolt Meter |
±20.000 mV ±50.0000 mV ±100.00 mV ±250.00 mV ±500.00 mV |
1 µV 2.5 µV 5.0 µV 12.5 µV 25 µV |
1 Gohm |
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Input Resolution |
16 bits (65,536 steps) |
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Transducer Excitation Output (standard) |
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Output Levels |
5V@100 mA, 10 @120 mA, 24V@50 mA (jumper
selectable) |
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Serial Data Output (standard) |
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Signal Types |
RS232 or RS485 (half or full duplex) |
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Dual Relay Output (standard) |
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Relay Type |
Two solid state relays, SPST, normally open,
Form A |
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Analog Output (standard) |
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Output Levels |
4-20 mA, 0-20 mA, 0-10 Vdc (jumper selectable) |
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Power Input |
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Standard Power |
85-264 Vac or 90-300 Vdc (DC operation not UL
approved) |
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Mechanical |
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Dimensions |
120 x 101 x 22.5 mm |
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Environmental |
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Operating Temperature |
0°C to 55°C |
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Pinout
Laureate Modbus & Serial
Output Transmitter
for Load Cell or Microvolt Input

For 4-wire load cell connection, jumper Pin 1 to Pin 2, and Pin 5 to Pin 6.
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Load Cell
Transmitter 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 in parallel can be powered by a single Laureate transmitter at 5V excitation. The excitation and sense points of the four bridges are connected in parallel through a summing box. | |
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Ordering
Guide
Laureate Modbus & Serial Output Transmitter
for Load Cell or Microvolt Input
Click on the radio buttons to build a model number with pricing (shown below the Ordering Guide).
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Configured model number |
LTM2000WM |
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Configured price per model |
$290 |
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Quantity |
1 |
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Extended price |
$290 |
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