Features
- 20, 50, 100, 250 and 500 mV full-scale input ranges
- Accuracy ±0.01% of reading ± 2 counts
- 4 or 6-wire hookup to avoid power supply and lead resistance effects
Certificates of Compliance
The Laureate 4-20 mA, 0-20 mA, 0-10V or -10V to +10V and RS232/RS485 output transmitter for load cell or microvolt input 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. The selected input range for the full 0-20 mA output span can be as wide as ±99,999 counts or as narrow as 150 counts, limited only by considerations of electrical noise and time constants of the programmable moving average digital filter. The unit's serial data is accurate to ±0.01% of reading ±2 counts in ratiometric load cell mode and ±0.01% of full scale in ±2 counts in absolute microvolt mode.
All signal conditioner board ranges are factory-calibrated, with calibration factors for each range securely stored in an onboard EEPROM. These factors can be scaled via software to accommodate external shunts, enabling field replacement of signal conditioner boards without necessitating recalibration of the associated transmitter. For optimal accuracy, factory recalibration is recommended annually. All Laurel Electronics instruments undergo factory calibration using the industry-leading Fluke calibrators, which are recalibrated yearly and certified traceable to national standards, ensuring the highest level of precision and reliability.
The optional extended Laureate computer board enhances Laureate transmitter by displaying rates derived from successive readings and enabling highly accurate custom curve linearization. For example, it can calculate liquid volume or flow rate in a horizontal cylindrical tank using levels from a 4-20 mA transmitter. Setup is straightforward: users input up to 180 data points into a spreadsheet or text file, and the computer calculates spline-fit segments, which are then downloaded to the transmitter for precise operation.
Laureate Transmitters are easily programmed with Laurel’s free Instrument Setup Software, downloadable from our website and compatible with Windows PCs, requiring a data interface board for setup.
High read rate of up to 50 or 60 conversions per second, the Laureate™ LT Series transmitter uses Concurrent Slope (US Pat. 5,262,780) analog-to-digital conversion to integrate signals over a full power line cycle (50 Hz or 60 Hz). This read rate enables peak and valley capture, real-time computer interfacing, and control applications. Peak and valley values are automatically captured and can be viewed using Laurel’s free Instrument Setup Software (compatible with Windows PCs) or transmitted as serial data.
Standard Hardware Features of Laureate LT Transmitters Include:
- Serial communications output, (isolated), RS232 or RS485 (half or full duplex), jumper selectable. 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 is simpler than the Modbus protocol and is recommended when all devices are Laureates.
- 4-20 mA, 0-10V or -10V to +10V analog transmitter output, (isolated), jumper-selectable and user scalable. All selections provide 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. Note that Ethernet data I/O is provided by Laurel's LTE series transmitters.
- Dual solid state relays, (isolated), for alarm or control. Rated 120 mA at 130 Vac or 180 Vdc.
- Selectable transducer excitation output, (isolated), user selectable 5V@100 mA, 10V@120 mA, 12V@100mA, or 24V@50 mA.
- Power 85-264 Vac, (isolated), low-voltage 10-48 Vdc or 12-32 Vac power is optional.
Digital signal filtering modes can be selected to ensure stable readings in electrically noisy environments.
- An unfiltered selection provides true peak and valley readings and aids in control applications.
- A batch average filter selection averages each 16 conversions.
- An adaptive moving average filter selection provides a choice of 8 time constants from 80 ms to 9.6 seconds. When a significant change in signal level occurs, the filter adapts by briefly switching to the shortest time to follow the change, then reverts back to its selected time constant. An Auto setting selects the time constant selection based on signal noise.
Two tare functions: auto-tare and manual tare. In auto-tare, an input line is grounded by an external pushbutton. This causes the current weight, which is normally the empty weight of the container to be stored in memory as an offset. In manual tare, the tare value can be entered manually via a control input pushbutton or using Laurel's free Instrument Setup Software.
Peak and valley values are automatically captured. These may be displayed via Laurel's free Instrument Setup Software, which runs on a PC under MS Windows or can be transmitted as serial data.
Two control inputs (CMOS/TTL levels, logic 0 = tied to digital ground, logic 1 = open) or dry contacts that can be set to control / activate 14 transmitter commands.
An (isolated) 5, 10, 12, or 24 Vdc excitation output is standard to power transducers or two-wire transmitters. Ratiometric operation, which automatically compensates for changes in the applied excitation, is jumper selectable for applications, such as bridges, where the signal to be measured is proportional to the excitation level.
LT series DIN rail Transmitters & signal conditioners can be interfaced to a wide range of sensors and transducers using one of seven available plug-in signal conditioner boards. The transmitters duplicate the high performance (high accuracy and high read rate) and extensive programmable features of Laureate 1/8 DIN digital panel meters, counters, and timers. They utilize the same signal conditioners boards, much of the same firmware, and Laurel's free Windows-based Instrument Setup Software. They come in a compact DIN rail mount package with detachable screw-clamp connectors for easy wiring.
The LT series Transmitters feature isolated, user-selectable analog outputs (4-20 mA, 0-20 mA, 0-10V, or -10V to +10V), an RS232 or RS485 serial data interface, and dual 120 mA solid state AC/DC relays. Most models, except those with temperature or AC RMS signal conditioners, include an isolated 5, 10, 12, or 24 Vdc transducer excitation output.
Load Cell Transmitter Connections
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In 4-wire connection, the excitation and sense lines are tied together. The transmitter can make ratiometric corrections for supply voltage variations, but does 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 can be powered by a single Laureate, whose excitation output is rated 120 mA at 10V. The excitation and sense points of the four bridges are connected in parallel. The load cell outputs will be averaged if the load cells have the same sensititivity in mV/V. |
Connecting Laureate LT Transmitters to a Local Area Network (LAN)
Up to 30 Laureate LT Transmitters and/or Digital Panel Meters can be configured for RS485 and daisy-chained to an LT Transmitter for seamless LAN integration. Alternatively, Laurel LTE series Ethernet transmitters can connect directly to a LAN via an Ethernet cable. Setup for both configurations is streamlined using Laurel’s free Instrument Setup Software, which simplifies node discovery and transmitter configuration.
Flexible Communication Options for LT Transmitters
Laureate Transmitters can be equipped with Laurel communication boards to support various interfaces and protocols. These include serial interfaces with ASCII or Modbus RTU protocols, and Ethernet interfaces with web access, ASCII, or Modbus TCP/IP protocols, ensuring versatile connectivity for your commercial applications.
| LT Transmitter Signal Input & Function | Model Series | Analog Output | RS232 & RS485 | Dual Relays | |
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| 1 | DC Input Voltage and Current | LT-DC |  |
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| 2 | AC RMS Voltage or Current | LT-RMS | |
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| 3 | Process Voltage or Current | LT-P | |
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| 4 | Weighing Applications | LT-WA | |
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| 5 | Load Cell & Microvolt Signals | LT-WM | |
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| 6 | Thermocouple (Types J, K, T, E, N, R, S) | LT-TC | |
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| 7 | RTD Temperature | LT-RTD | |
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| 8 | Resistance in Ohms | LT-R | |
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| 9 | Frequency, Rate, Speed | LT-FR | |
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| 10 | Pulse Input Totalizer | LT-FR | |
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| 11 | Process Signal Totalizer | LT-VF | |
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| 12 | Sum, Difference, Ratio, Product of 2 Inputs | LT-FR | |
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| 13 | Batch Controller Pulse Input | LT-FR | |
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| 14 | Batch Controller Analog Input | LT-FR | |
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| 15 | On/Off Duty Cycle | LT-FR | |
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| 16 | Stopwatch Timing for Single Events | LT-FR | |
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| 17 | Average Time of Periodic Events | LT-FR | |
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| 18 | AC Phase Angle and Power Factor | LT-FR | |
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| 19 | Quadrature Position or Rate | LT-QD | |
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Load Cell, Strain Gauge and Microvolt input signal transmitter
| Analog Input | Range | Scaling | Input Ohms | Error at 25°C |
|---|---|---|---|---|
| Load Cell Input | ±20.000 mV | -99,999 to +99,999 zero adjust. 0 to ±99,999 span adjust. |
1 GΩ | ±0.01% of rdg ± 2 cts |
| ±50.0000 mV | ||||
| ±100.00 mV | ||||
| ±250.00 mV | ||||
| ±500.00 mV | ||||
| Microvolt Input | ±20.000 mV | 1 µV | 1 GΩ | ±0.01% of FS ± 2 cts |
| ±50.0000 mV | 2.5 µV | |||
| ±100.00 mV | 5.0 µV | |||
| ±250.00 mV | 12.5 µV | |||
| ±500.00 mV | 25 µV | |||
| Reading Resolution | 16 bits (65,536 steps) | |||
| Reading Accuracy | ±0.01% of reading ± 2 counts in ratiometric mode, ±0.01% of full scale ± 2 counts in absolute mode |
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| Update Rate, Max | 50/sec at 50 Hz, 60/sec at 60 Hz | |||
| Max applied voltage | 100 V | |||
| Recalibration: All ranges are calibrated at the factory. Recalibration is recommended every 12 months. | ||||
| A-to-D Conversion | ||||
| Technique | Concurrent Slope™ (Pat 5,262,780) | |||
| A-to-D rate | 60/s at 60 Hz, 50/s at 50 Hz | |||
| Output update rate | 56/s at 60 Hz, 47/s at 50 Hz | |||
| Display update rate | 3.5/s at 60 Hz, 3/s at 50 Hz | |||
| Accuracy | ||||
| Error at 25°C | 0.01% FS ± 2 counts (except 5A range) | |||
| Span tempco | 0.003% of reading/°C | |||
| Zero tempco | 0.1 count/°C | |||
| Noise Rejection | ||||
| CMR, DC to 60 Hz | 130 dB | |||
| NMR at 50/60 Hz | 90 dB with min filtering | |||
| Analog Output (standard) | ||||
| Output Levels | 4-20 mA, 0-20 mA, 0-10 Vdc, -10 to +10Vdc (user selectable) | |||
| Compliance, 4-20 mA | 10V (0-500Ω load) | |||
| Compliance, 0-10V | 2 mA (5 kΩ load or higher) | |||
| Output Resolution | 16 bits (65,536 steps) | |||
| Output Accuracy | 0.02% of output span plus conversion accuracy | |||
| Output Isolation | 250V rms working, 2.3 kV rms per 1 minute test | |||
| Excitation Output (standard) | ||||
| 5 Vdc | 5 Vdc ± 5%, 100 mA (jumper selectable) | |||
| 10 Vdc | 10 Vdc ± 5%, 120 mA (jumper selectable) | |||
| 12 Vdc | 12 Vdc ± 5%, 100 mA (jumper selectable) | |||
| 24 Vdc | 24 Vdc ± 5%, 50 mA (jumper selectable) | |||
| Output Isolation | 50 Vdc from signal ground | |||
| Ratiometric operation | Automatically compensates for changes in excitation level. | |||
| Dual Relay Output (standard) | ||||
| Relay Type | Two solid state relays, SPST, normally open, Form A | |||
| Load Rating | 120 mA at 140 Vac or 180 Vdc | |||
| Serial Data Output (standard) | ||||
| Signal Types | RS232 or RS485 (half or full duplex), jumper selectable | |||
| Data Rates | 300, 600, 1200, 2400, 4800, 9600, 19200 baud | |||
| Output Isolation | 250V rms working, 2.3 kV rms per 1 min test | |||
| Serial Protocols | Modbus TCP, Modbus RTU, Modbus ASCII, Laurel ASCII | |||
| Modbus Compliance | Modbus over Serial Line Specification V1.0 (2002) | |||
| RS232/485 Connector | Screw terminals for easy daisy chaining | |||
| Digital Addresses | 247 for Modbus, 31 for Laurel ASCII | |||
| Power Input | ||||
| Standard Power | 85-264 Vac or 90-300 Vdc | |||
| Low Power Option | 10-48 Vdc or 12-32 Vac | |||
| Power Frequency | DC or 47-63 Hz | |||
| Power Isolation | 250V rms working, 2.3 kV rms per 1 min test | |||
| Power Consumption at 24V | 1.5W typical, 3W with maximum excitation output | |||
| Environmental | ||||
| Operating Temp. | -40°C to 70°C (-40°F to 158°F) | |||
| Storage Temp. | -40°C to 85°C (-40°F to 185°F) | |||
| Relative Humidity | 95% at 40°C, non-condensing | |||
| Cooling Required | Mount transmitters with ventilation holes at top and bottom. Leave 6 mm (1/4") between transmitters, or force air with a fan. | |||
| Mechanical | ||||
| Enclosure | Rugged black polycarbonate housing material | |||
| Mounting | 35 mm rail per DIN EN 50022 | |||
| Dimensions | 129 x 104 x 22.5 mm case | |||
| Connectors | Detachable screw-clamp connectors for signal and power RJ45 jack for Ethernet | |||
| Tightening Torque | Screw terminal connectors: 5 lb-in (0.56 Nm) | |||
| Weight | Complete transmitter: 183 g (6.5 oz) | |||
| Replacement Case Screws | ||||
| Size | 6 | |||
| Thread Pitch | 6-19 | |||
| Length | 1/2" | |||
| Head Style | Pan Head | |||
| Drive Style | Phillips | |||
| Head Diameter | 0.256-0.270 | |||
| Head Height | 0.087-0.097 | |||
| Full/Partial Thread | Full | |||
| Drive Size | 2 | |||
| Material | Steel | |||
| Finished | Black Oxide | |||
| General | ||||
| Programming | Utilize Laurel's free Instrument Setup Software, which runs on a PC under MS Windows. | |||
| Security | Lockout options available using Laurel's free Instrument Setup Software. | |||
| Warranty | 3 years parts & labor | |||
| Recalibration: All ranges are calibrated at the factory. Recalibration is recommended every 12 months. | ||||
Transmitter Pinout
Free Instrument Setup Software for Series 2 Laureates
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| 1/8 DIN Digital Panel Meters | DIN Rail Transmitters |
Free Downloadable Windows-based Instrument Setup (IS) software (Data Interface Board Required) for use with our programmable Digital Panel Meters, Scale Meters, Counters, Timers, Remote Displays, and Transmitters, are an easy method to set up Laureate 1/8 DIN digital panel meters, counters, timers, remote displays, and DIN-rail transmitters, as explained in the Instrument Setup Software Manual. Laureate 1/8 DIN instruments can also be set up from the front panel, as explained in their respective Owners Manuals. Instrument Setup software is of benefit whether or not the PC is connected to the instrument.
- When the PC is connected to the instrument, Instrument Setup software can retrieve the setup file from the instrument or open a default setup file or previously saved setup file from disk View Setup, then provides graphical user interface (GUI) screens with pull-down menus applicable to input, display, scaling, filtering, alarms, communications, analog output, and front panel lockouts. Fields that are not applicable to the instrument as configured are either left out or grayed out. Clicking on any item will bring up a detailed Help screen for that item. After editing, the setup file can be downloaded, uploaded to the instrument, or saved to a disk. The same setup file can then be downloaded into multiple instruments.
- When the PC is not connected to the instrument, the above GUI screens can be used to set up a virtual instrument. The setup file can then be saved to disk. Switching toView Menu then brings up a screen with the required front panel programming steps. This view can be printed out for use at the instrument site and to serve as a hard copy record.
Download Free Instrument Setup Software
Installation
Set User Account Control (UAC) of MS Windows to "Never notifiy me" so that Instrument Setup Software can create directories. The UAC change screen can be reached as follows:
- Under Windows 7, click on the Windows Start button in the lower left of the desktop and enter "UAC" in the search field.
- Under Windows 8, navigate to Control Panel, then to the "User Accounts and Family Safety" section, and click on "Change User Account Control Settings."
- Under Windows 10, click on the Windows Start button in the lower left of the desktop, then on "Settings", and enter "UAC" in the search field.
- Reboot your computer for the changed UAC setting to take effect.
RJ11-to-DB9 cable with rear view of DB9 connector to PC
RS232 cable, meter to PC, P/N CBL01
Laureate 1/8 DIN Laureate instruments must be equipped with a serial communications board and be connected to the computer via a serial communications cable. The connection can be via RS232, RS485, USB or Ethernet. Following setup, the serial communications board may be removed from the instrument if desired. The wiring of the RS232 cable is illustrated above with end views of the two connectors.
Laureate LT Series transmitters come standard with a 3-wire serial interface, which can be jumpered for RS232 or RS485.
Laureate LTE Series transmitters come standard with an Ethernet interface.
Meter Setup Screens
Click on any of the reduced screens below for a full-size screen view, then click on the Back button of your browser to return to this page. The screens examples below are for a fully-loaded Series 2 Digital Panel Meter (DPM), which is connected to the PC via RS232. If the meter is a Series 1 meter (pre-2007), this is sensed by the software, and somewhat different screens are brought up. Please see Series 1 setup screens.
Welcome Screen
From the computer desktop, click on Start > Programs > IS2 > IS2. Or click on the IS icon on your desktop. This splash screen will be displayed for three seconds. The software revision number is in the lower right.
Communications Selection Screen
Specify your desired communication protocol and the serial communications bus type, which should match the jumper setup of the instrument. Select None if the PC is not connected to the instrument.
Establish Communications Screen
If you selected RS-232, you will be asked to specify the PC Com Port and Baud Rate, which should match the jumper setup of the instrument. Click on Establish. With the right settings, the Communications Established field will light up in green, and the Meter Type will be recognized. If so, click onMain Menu.
Main Menu Screen
Click on File > Default Setup to retrieve the default setup file from disk for your type of meter. Click on File > Open Setupto retrieve a previously saved setup file from disk or on File > Save Setup to save your edited setup file to disk. Click onDPM > Get Setup to retrieve the setup file from your meter or on DPM > Put Setup to download your edited setup file into the meter.
DPM Input + Display Setup Screen
From the Main Menu, click on View > Setup, then on theInput+Display tab. You can now specify the meter hardware, signal type, display mode, and functions of control inputs A and B. Clicking on any item brings up a pull-down menu with the available choices.
DPM Scaling Setup Screen
Click on the Scaling tab, which provides three scaling methods to relate the signal to the displayed reading: 1) Scale and Offset method, 2) Coordinates of two points method, and 3) Reading Coordinates of Two Points method. The last method uses actual high and low signals, and the computer will prompt you.
DPM Filter Setup Screen
Click on the Filter tab, which allows you to specify the digital filter time constant (if any), the adaptive filter threshold, and whether Peak / Valley values are filtered or unfiltered. As for all setup screens, clicking on the F1 key while an item is highlighted brings up a Help screen for that item, as illustrated.
DPM Relay Alarms Setup Screen
Click on the Relay Alarms tab, which allows you to set up Alarms 1 and 2 for the optional dual relay output board. Clicking on any of the four numeric fields changes these to green and brings up a special field to enter the desired numeric value, which is tied to the displayed reading.
DPM Communications Setup Screen
Click on the Communications tab so set up serial communications. In particular, you can special the Serial Protocol and the meter address if multiple meters are to be addressed on the same serial data line.
DPM Analog Output Setup Screen
Click on the Analog Out tab so set up the optional analog output board. Three output ranges are selectable, the endpoints of which can be tied to user-specified High and Low readings.
DPM Lockouts Setup Screen
Click on the Lockouts tab to check off menu items which will no longer be accessible from the front panel of the meter. This will simplify meter operation and prevent unintended setup changes.
Meter Setup Utilities
DPM Front Panel Setup Screen
As an aid to programming the meter from the front panel when a serial connection is not available, you can return to the Main Menu and click on View > Menu. The required sequence of front panel screens will then be displayed. Click on any step in the sequence for the meaning of each digit, as illustrated for the FILtEr step. For a hardcopy, simply press on Print.
DPM Jumper Setup Screen
Specify your desired communication protocol and the serial communications bus type, which should match the jumper setup of the instrument. Select None if the PC is not connected to the instrument.
DPM Jumper Setup Screens
Click on any of the displayed plug-in boards, and you will be presented with the jumper positions and electrical connections for your selected board. This minimizes the need to refer to the printed manual.
DPM Commands Screen
This page allows you set up external input, serial communications, an analog output proportional to the display (optional), and lockouts for Laureate digital counters. The grayed out area at the top right of the screen applies to Laureate remote displays.
Graphical Output Screens (not available with Ethernet)
From the Main Menu, click on Readings if your PC is connected to the meter. A pull-down menu then offers three choices: List, Plot and Graph.
- List presents the latest readings in a 20-row by 10-column table. Press Pause at any time to freeze the display. This is one method to capture peak readings.
- Plot generates a plot of readings vs. time in seconds. It effectively turns the DPM-PC combination into a printing digital oscilloscope.
- Graph generates a histogram where the horizontal axis is the reading and the vertical axis is the number of occurrences of readings. The display continually resizes itself as the number of readings increases.
DPM Calibration Screens
Click on the Scaling tab, which provides three scalClick on the Scaling tab, which provides three scaling methods to relate the signal to the displayed reading: 1) Scale and Offset method, 2) Coordinates of two points method, and 3) Reading Coordinates of Two Points method. The last method uses actual high and low signals, and the computer will prompt you.
Frequency Meter Calibration Screen
Calibration of the quartz crystal of the Laureate frequency meter requires the input of a known frequency from a calibrator. Apply the frequency, then enter the frequency in Hertz. Calibration will be automatic, with storage of the calibration factor stored in non-volatile memory.
Dimensions
Dimensioned CAD assembly drawings in EPRT, STEP, x_t, .dwg, pdf file formats: Laureate-transmitter-case.zip (zipping prevents browser from opening CAD files as text files).
CAL-Analog
Certificate of Calibration
$65.00
CBL02
USB-to-RS232 Adapter Cable
$47.00
CBL04
RS232 Cable for LT Transmitters
$47.00CBL12
12-foot Power Cable
$47.00CBL6
6-foot Power Cable
$41.00What Is the LT DIN Rail Analog Transmitter for Load Cell, Strain Gauge and Microvolt Input?
In the field of industrial automation and instrumentation, accurate measurement and signal handling are vital. A key device in this sector is the analog transmitter, particularly when managing inputs from load cell strain gauges. This section offers a detailed examination of the LT DIN Rail Analog Transmitter, focusing on its purpose, practical uses, and integration with load cells via serial data communication and analog outputs.
What Is an LT DIN Rail Analog Transmitter?
The LT DIN Rail Analog Transmitter is a specialized tool engineered to transform faint microvolt signals from load cell strain gauges into reliable, usable analog and digital outputs. These transmitters are typically mounted on DIN rails, which are standardized metal supports designed to simplify the installation of industrial control equipment in electrical enclosures.
Key Features
- Load Cell Strain Gauge Input: Load cells function as sensors that detect force or weight, converting it into an electrical signal. The strain gauge within the load cell produces a microvolt-level signal based on the applied force, which the transmitter is designed to interpret accurately.
- Microvolt Signal Sensitivity: The delicate microvolt signals from strain gauges are prone to noise and interference. The LT transmitter enhances these signals, ensuring precise measurements and consistent transmission.
- Analog Output: After processing the microvolt signal, the transmitter generates a standard analog output, such as 4-20 mA or 0-10V, which can be readily interpreted by industrial devices like programmable logic controllers (PLCs) for additional control and analysis.
- Serial Data Communication: In addition to analog outputs, the transmitter supports digital transmission via serial data protocols such as RS-485 or RS-232, enabling real-time data tracking, remote adjustments, and seamless integration into advanced industrial networks.
- DIN Rail Mounting: Built for easy installation on a DIN rail, this transmitter fits smoothly into existing control panels and electrical enclosures, with its standardized mounting system streamlining wiring and upkeep.
Applications
LT DIN Rail Analog Transmitters are extensively utilized in industries where precise weight or force measurement is paramount. Notable applications include:
- Industrial Weighing Systems — employed in conveyor systems, hoppers, and batching operations to monitor and regulate material weight.
- Force Measurement in Manufacturing — utilized in equipment like presses, tension analyzers, and material testing units for accurate force assessment.
- Process Control — indispensable in processes requiring detailed oversight of force or weight, such as chemical blending or food production.
Advantages of Using an LT DIN Rail Analog Transmitter
- High Precision: The capability to amplify and process microvolt signals ensures accurate measurements, essential for tasks like material testing or fine-scale weighing.
- Adaptable Communication: The combination of analog outputs and serial data communication allows the transmitter to connect with a broad spectrum of industrial devices and systems.
- Effortless Installation: The DIN rail mounting design simplifies integration into existing control setups, enhancing installation efficiency.
- Durability: Constructed to perform reliably in industrial settings, these transmitters maintain robust operation even in challenging environments.
Where Is an LT DIN Rail Analog Transmitter for Load Cell Strain Gauge Microvolt Input Used?
In industrial and scientific settings, accuracy and dependability are crucial, particularly when managing sensitive measurements from load cells and strain gauges. This section outlines the primary areas of use, highlighting its substantial impact across various sectors.
Industrial Automation and Process Control
- Material Weighing and Batching Systems — transforming the subtle microvolt signals from load cells into practical analog outputs and digital data that integrate with control systems, essential for consistent product quality.
- Force Measurement in Manufacturing — in fields like automotive and aerospace, strain gauges monitor force, pressure, or tension in components, with the transmitter providing outputs to control systems to keep forces within safe limits.
Laboratory and Research Applications
- Structural Testing — in civil engineering labs, reliably transmitting minute strain gauge signals to data acquisition systems for detailed stress and strain analysis.
- Material Fatigue Testing — gathering comprehensive data on material behavior under repeated loads to aid in developing more resilient products.
Weighing and Scale Systems
- Commercial Weighing Systems — delivering accurate weight data that supports packaging control, labeling accuracy, and product consistency in food processing, logistics, and packaging.
- Vehicle Weighing Systems — for weighbridges and axle weighing, ensuring accurate conversion and transmission of load cell signals to monitoring systems.
Energy Sector
- Wind Turbine Monitoring — processing blade and structural strain signals for real-time monitoring, preventing structural failures.
- Pipeline Monitoring — converting microvolt signals into data to detect leaks or weaknesses in oil and gas pipelines.
Medical Equipment
- Prosthetics and Orthotics — ensuring accurate data transmission to monitoring systems for fine-tuning optimal performance and comfort.
- Biomedical Research — converting joint or limb force signals into analyzable data, advancing biomechanical understanding.
Conclusion
An LT DIN Rail Analog Transmitter with serial data communication and analog outputs is a cornerstone component in industrial automation, especially for handling low-level signals from load cell strain gauges. Its ability to enhance, convert, and transmit these signals ensures precise measurements throughout industrial processes, boosting operational effectiveness and accuracy — whether applied in manufacturing, process management, material evaluation, structural testing, energy management, or medical research. As the need for precision and reliability increases, the importance of these transmitters will continue to grow, driving technological and safety innovations across the automation systems that depend on them.
Load Cell, Strain Gauge and Microvolt Input Transmitter Frequently Asked Questions
What's the practical difference between ratiometric mode and absolute microvolt mode?
Ratiometric mode measures the signal relative to the transmitter's own excitation voltage, so small excitation fluctuations largely cancel out — this is the standard mode for most load cells. Absolute microvolt mode instead measures against a fixed internal reference, appropriate when the sensor's output isn't tied to the transmitter's excitation supply.
Why does the specified accuracy differ between the two modes?
Ratiometric mode is specified as 0.01% of reading ±2 counts, while absolute mode is specified as 0.01% of full scale ±2 counts. The distinction reflects how each mode references its measurement: a reading-based percentage in ratiometric mode versus a fixed-scale percentage in absolute mode.
How many load cells can a single transmitter support?
Up to four 350-ohm load cells can be wired in parallel to a single transmitter, sharing its excitation output (rated 120 mA at 10V). Their outputs are averaged together, provided the load cells have matching sensitivity in mV/V.
When should a 6-wire connection be used instead of 4-wire?
6-wire connections separate the sense lines from the excitation lines, eliminating the effect of lead resistance on the reading. This matters most on long cable runs or in outdoor installations with significant temperature swings, where 4-wire lead resistance effects would otherwise show up as measurement error.
What does the digital zero and span adjustment actually change?
Zero and span adjustment maps the raw input signal to a displayed and transmitted reading in whatever engineering units the application needs — zero can be set anywhere from -99,999 to +99,999, and span from 0 to ±99,999, independent of the physical mV input range selected.
Is the excitation output the same as the analog output?
No — the excitation output (5V, 10V, 12V, or 24V DC, jumper selectable) powers the load cell or sensor itself and carries its own isolation rating (50 Vdc from signal ground), while the analog output (4-20 mA, 0-20 mA, 0-10V, or -10 to +10V) is a separate, independently isolated retransmission of the measured value.
What's the maximum applied voltage this transmitter's input can tolerate?
The specified maximum applied voltage on the load cell/microvolt input is 100V, which is a protection limit rather than an operating range — actual signal ranges top out at ±500.00 mV.
Can this transmitter be used for something other than weighing?
Yes — while weighing is the most common use, any sensor producing a millivolt-level ratiometric or absolute signal, such as certain pressure transducers or custom strain-based sensors, can be read by the same hardware, provided its output falls within the transmitter's supported ranges.
What is auto-tare, and how does it differ from manual tare?
Auto-tare zeroes out the current reading (typically an empty container's weight) automatically when an external pushbutton grounds a designated input line. Manual tare instead lets a specific tare value be entered directly via a control input or Laurel's setup software.
Does this transmitter support the same networking options as the DC voltage/current version?
Yes — up to 30 LT Transmitters and/or Digital Panel Meters can be daisy-chained on RS485 for LAN integration, or an LTE series Ethernet transmitter can be used for a direct Ethernet connection instead.
Load Cell, Strain Gauge and Microvolt Transmitter Questions From the Field
My scale reading drifts slowly even though the load on it hasn't changed — what should I check first?
Slow drift with a genuinely stable load is commonly traced to temperature effects on the load cell or its cabling rather than the transmitter itself; correlating the drift against ambient temperature changes over the same period is a typical first diagnostic step.
Why does my reading change when I touch or move the cabling near the load cell?
Because this is a microvolt-level signal, it's highly sensitive to noise picked up by nearby cabling, especially with degraded shielding or a poor ground connection; checking cable shielding continuity and connector integrity is the standard first troubleshooting step.
One load cell in a four-cell parallel setup seems to be skewing the total reading — how is that isolated?
The standard approach is to disconnect and test each load cell individually against a known reference load before reconnecting it to the parallel arrangement, since a single faulty or mismatched-sensitivity cell can distort the averaged reading in a way that's difficult to isolate once all four are summed.
My reading is correct at zero but off across the rest of the range — what does that suggest?
A correct zero paired with an inaccurate span usually points to a span/scaling mismatch between the load cell's actual rated output and the value entered during setup, rather than a wiring fault, since a wiring problem would typically disturb the zero reading too.
Why would switching from 4-wire to 6-wire wiring change my calibration?
Moving to 6-wire sensing changes how lead resistance is compensated, so a calibration performed under a 4-wire connection won't necessarily carry over correctly after rewiring to 6-wire; recalibrating after any wiring configuration change is the recommended practice.
My reading is unstable specifically near variable-frequency drives or large motors — why?
Variable-frequency drives are a well-documented source of electrical noise that couples easily into low-level signal wiring; verifying proper shielding, grounding, and physical separation from the noise source is the standard remedy before suspecting a transmitter fault.
Can moisture or humidity affect a load cell reading in the field?
Yes — moisture ingress into a load cell body or its junction box is a commonly documented cause of erratic or drifting readings, since it can create unintended resistance paths across the bridge circuit; checking for condensation or water ingress is a standard step when a previously stable installation starts behaving erratically.
