LT DIN Rail Analog Transmitters with Serial Data Communication and Analog outputs for Scale and Weighing Applications

LT DIN Rail Analog Transmitters with Serial Data Communication and Analog outputs for Scale and Weighing Applications

Price: $334.00
  • P/NLT20SG
- +

Features

  • Transmitter optimized for weighing applications
  • Accuracy of 0.01% of reading ± 2 counts
  • 4- or 6-wire hookup to avoid lead resistance effects
  • 10V excitation supply for up to four 350-ohm load cells in parallel
  • Count by 1, 2, 5, 10, 20, 50 or 100 with rounding
  • Transmitter toggles between gross or net weight
  • Auto-tare or manual tare, with tare value stored in non-volatile memory
  • All input ranges are user selectable and factory calibrated
  • Up to 60 conversions per second, Ideal for peak or valley capture
  • Digital span adjust from 0 to ±99,999, zero adjust from -99,999 to +99,999
  • 4-20 mA, 0-20 mA, 0-10V or -10V to +10V transmitter output, (isolated)
  • Analog output resolution 0.0015%  of span, accuracy ±0.02%  of span
  • RS232 or RS485 serial data, Modbus or Laurel ASCII protocol (isolated)
  • Dual 120 mA solid state relays for alarm or control (isolated)
  • 5V, 10V, 12V, or 24V dc transducer excitation output (isolated)
  • Power 85-264 Vac / 90-300 Vdc or 10-48 Vdc / 12-32 Vac (isolated)
  • DIN rail mount housing, 22.5 mm wide, detachable screw-clamp connectors
  • Operating temperature from -40°C to 70°C (-40°F to 158°F)
    Optional - Extended allows up to 180 data points for custom curve linearization and a rate derived from consecutive readings.

The Laureate™ LT Series DIN rail analog transmitter with serial data communication and analog outputs for versatile connectivity.

The digitally programmable transmitter features two relays for alarm or control. The series offers exceptional accuracy of 0.01% of reading ± 2 counts, with high read rates at up to 60 or 50 conversions per second. The LT Series transmitters offer the same high performance, signal conditioning, and programmable features as Laureate digital panel meters, counters, and timers.


The Laureate 4-20 mA, 0-20 mA, 0-10V or -10V to +10V and RS232/RS485 output transmitter for scale weighing applications offers the same high performance, signal conditioning, and programmable features as Laureate digital panel meters, counters, and timers. It provides six voltage input ranges and four current input ranges, all factory calibrated and jumper selectable. This compact, inexpensive, and highly accurate transmitter features special firmware for weighing applications. It is available with the Laureate load cell or DC signal conditioner board. If you do not need the special weighing firmware, consider using the Laureate load cell transmitter or Laureate process transmitter.

Power

The DC signal conditioner board can used in lieu of the load cell signal conditioner board, be set to ratiometric operation, and be used with the transmitter's 5 Vdc or 10 Vdc excitation. It's most sensitive full-scale range is ±200 mV with 10 µV resolution, while the load cell signal conditioner board offers most sensitive ranges of ±20 mV and ±50 mV, both with 1 µV resolution. Transmitters with both boards offer an accuracy of 0.01% of full scale ± 2 counts.

Display & Setpoint Functions for Weighing Applications

  • Relay setpoint offset. The ON/OFF setpoint control action can be programmed to occur with a specified offset. For instance, if bags are to be filled to 100 lbs and the material delivery spout is known to hold and dispense an additional 2.5 lbs following shut-off, an offset of -2.5 lbs can be programmed. The setpoint can then be set to 100 lbs, and the filling valve will be automatically shut off when the measured weight reaches 97.5 lbs.
  • Count-by function. The weight transmitter can be programmed so that it can be displayed via Laurel's Instrument Setup Software,  which runs on a PC under MS Windows, is rounded off to multiples of 1, 2, 5, 10, 20, 50 or 100. For example, if count-by 10 is selected, the transmitter will display 20 for an internal count of 15 to 24.
  • Fixed right-hand dummy zero. The transmitter can be shifted to the left for a fixed zero to the right, allowing values up to 999,990. The right-hand zero precludes the use of decimal points.
  • Auto-zero function. An auto-zero limit from 0 to 9 counts can be programmed to compensate for load cell drift. Whenever the transmitter comes to rest within that limit from zero, it will auto-zero. Entering 0 disables auto-zero.

Easy scale calibration is achieved using a simple two-point calibration method. First, the desired LO IN reading is set to 0, and the desired HI IN reading is set to a desired value. With no weight on the scale, a button is pushed for LO IN. With a known weight on the scale, that button is pushed again for HI IN. The transmitter then automatically computes scale and offset for readout up to five digits in weight units.

Scale and offset can be provided by either of two user-selectable methods:

  • With the coordinate reading method, the transmitter reads the high and low signal values, and the user enters the desired high an low reading values. The transmitter then calculates the span multiplier and offset. This method is ideal if an external calibration reference is available.
  • With the manual coordinate method, the user enters the high and low input values in Volts plus the desired high and low reading values. This method is suitable if no external calibration reference is available.

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 power supply variations. With 6-wire load connection, it also compensates for lead resistance, allowing long cable runs.

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.

Removable screw terminal connections of Laurel transmitters

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.

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.

Laurel network with Ethernet-to-analog converter board

Scale input transmitter for scale weighing applications

Full-Scale Input Input Impedance Zero Adjust Span Adjust Error at 25°C
± 200.00 mV 1 GΩ      
± 2.0000 V 1 GΩ -99,999 0 to 0.01% FS
± 20.000 V 10 MΩ to +99,999 ±99,999 ± 2 counts
± 20.000 mA 10 Ω      
Recalibration: All ranges are calibrated at the factory. Recalibration is recommended every 12 months.
Display
Readout 5 LED digits, 7-segment, 14.2 mm (.56"), red or green
Range -99999 to +99999
  -999990 to +999990 (with fixed selectable right-hand zero)
Rounding Count by 1, 2, 5, 10, 20, 50, 100
Indicators Four LED lamps
Accuracy
Error at 25°C 0.01% FS ± 2 counts
Span tempco 0.0015% of reading/°C
Zero tempco 0.1 µV/°C (use auto-zero when temperature changes)
Calibration Method 2 points using zero weight and known weight
Noise Rejection
CMR, DC to 60 Hz 130 dB
NMR at 50/60 Hz 90 dB with min filtering
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 56/s at 60 Hz, 47/s at 50 Hz
Display update 3.5/s at 60 Hz, 3/s at 50 Hz
Power Supply Boards (one required)
Voltage, standard 85-264 Vac or 90-300 Vdc
Voltage, optional 12-32 Vac or 10-48 Vdc
Frequency DC or 47-63 Hz
Power  consumption (typ. with four 350Ω load cells at 10V) 2.4W @ 120 Vac, 2.7W @ 240 Vac, 2.5W @ 10 Vdc, 2.6W @ 20 Vdc, 2.75W @ 30 Vdc, 3.0W @ 40 Vdc, 3.35W @ 48 Vdc
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.
Analog Output Board (one optional)
Output levels 4-20 mA, 0-20 mA, 0-10V
Current compliance 2 mA at 10V ( > 5 kΩ load)
Voltage compliance 12V at 20 mA (< 600 Ω load)
Scaling Zero and full scale adjustable from -99999 to +99999
Resolution 16 bits (0.0015% of full scale)
Isolation 250V rms working, 2.3 kV rms per 1 min test
Relay Output Boards (one optional)
Dual magnetic relays 2 Form C, 8A max, 440Vac or 125Vdc max, 2500VA or 300W
Quad magnetic relays 4 Form A (NO), 8A max, 440Vac or 125Vdc max, 2500VA or 300W
Dual solid state relays 2 Form A (NO), AC or DC, 0V - 400V, 120Ma, 35Ohms (max at On-State)
Quad solid state relays 4 Form A (NO), AC or DC, 0V - 400V, 120Ma, 35Ohms (max at On-State)
Relay commons Isolated commons for dual relays or each pair of quad relays
Relay isolation 250V rms working, 2.3 kV rms per 1 minute test
Relay latching modes Latching or non-latching
Relay active modes Active on or off, active high or low
Hysteresis modes QA passband mode, split hysteresis, span hysteresis
Communication Boards (one optional)
Board selections RS232RS485 with dual RJ11 connectors, RS485 with dual RJ45 connectors, USB, USB-to-RS485 gatewayWiFi with built-in antenna plus USB & RS485, WiFi with external antenna plus USB & RS485
Protocols Modbus RTU, Modbus ASCII, Modbus TCP (Ethernet), Laurel ASCII
Digital addresses 247 (Modbus), 31 (Laurel ASCII),
Isolation 250V rms working, 2.3 kV rms per 1 min test
Environmental
Operating temperature -40°C to 70°C (-40°F to 158°F)
Storage temperature. -40°C to 85°C (-40°F to 185°F)
Relative humidity 95% at 40°C, non-condensing
Protection NEMA-4X (IP-65) when panel mounted
Mechanical
Enclosure 1/8 DIN, high impact plastic, UL 94V-0, color: black
Mounting 1/8 DIN panel cutout required: 3.622" x 1.772" (92 mm x 45 mm).
Dimensions 4.68" x 2.45" x 5.64" (119 mm x 62 mm x 143 mm) (W x H x D)
Maximum panel thickness 4.5 mm (0.18")
Tightening Torque - Connectors Screw terminal connectors: 5 lb-in (0.56 Nm)
Tightening Torque - Pawls Digital Panel Meter Case Pawls: 5 lb-in (0.56 Nm)
Weight of base meter 210 g (7.4 oz) typical (DPM, counter, timer, 6-digit remote display)
Weight of option boards 30 g (1.0 oz) typical per board (analog output, relay output, communications)
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 Methods Four front panel buttons or via Laurel's free Instrument Setup Software, which runs on a PC under MS Windows. 
Security Lockout options include using the front panel buttons, Laurel's free Instrument Setup Software, or a hardware jumper.
Warranty 3 years parts & labor
Recalibration: All ranges are calibrated at the factory. Recalibration is recommended every 12 months.

Transmitter Pinout

Laureate LT transmitter pinout

 

Free Instrument Setup Software for Series 2 Laureates

Digital Panel Meter Laurel Electronics Digital Transmitters
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.
Meter board with USB Type-B connector

RJ11-to-DB9 cable with rear view of DB9 connector to PC

Laurel USB cable, P/N CBL05

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.

Laurel Dual Channel Pulse Input Rate Meter
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.
more
Setup Screen 02s for Digital Panel Meters and Digital Transmitters
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.
more
Setup Screen 3 for Digital Panel Meters and Digital Transmitters
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.
more
Setup Screen 4 for Digital Panel Meters and Digital Transmitters
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.
more
Setup Screen 5 for Digital Panel Meters and Digital Transmitters
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.
more
Setup Screen 6 for Digital Panel Meters and Digital Transmitters
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.
more
Setup Screen 7 for Digital Panel Meters and Digital Transmitters
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.
more
Setup Screen 8 for Digital Panel Meters and Digital Transmitters
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.
more
Setup Screen 9 for Digital Panel Meters and Digital Transmitters
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.
more
Setup Screen 10 for Digital Panel Meters and Digital Transmitters
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.
more
Setup Screen 11 for Digital Panel Meters and Digital Transmitters
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.
more

Meter Setup Utilities

Setup Screen 12 for Digital Panel Meters and Digital Transmitters
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.
more
Setup Screen 13 for Digital Panel Meters and Digital Transmitters
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.
more
Setup Screen 14 for Digital Panel Meters and Digital Transmitters
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.
more
Setup Screen 15 for Digital Panel Meters and Digital Transmitters
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.
more
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: ListPlot 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.
    more 
  • 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.
    more
Setup Screen 18 for Digital Panel Meters and Digital Transmitters
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.
more
Setup Screen 19 for Digital Panel Meters and Digital Transmitters
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.
more

 

Dimensions

Laurel transmitter case

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

$47.00

CBL12

12-foot Power Cable

$47.00

CBL6

6-foot Power Cable

$41.00
Ordering Guide
Part Number as Configured: LT20SG
Price as Configured: $334.00

Click on the Option Board Links for More Product Information

Base Item
$164.00
Main Board
$0.00
Extended allows up to 180 data points for custom curve linearization and a rate derived from consecutive readings.
$33.00
Power (Isolated)
$89.00
$89.00
Signal Input (Isolated)
$81.00
$156.00
$81.00
$156.00
$164.00
Specify min signal and displayed reading, max signal and displayed reading.20-500 mV. Default excitation of 10V for up to four 350-ohm load cells in parallel.
$239.00
Part Number as Configured:
LT20SG
Price as Configured:
$334.00
Quantity:
- +
Extended Price:
$334.00

Understanding the Laureate™ LT Series DIN Rail Transmitter for Scale & Weighing Applications

The Laureate™ LT Series DIN rail transmitter for scale weighing applications provides six voltage input ranges and four current input ranges, all factory calibrated and jumper selectable, featuring special firmware for weighing. It's available with either the Laureate load cell or DC signal conditioner board. The DC signal conditioner board can be used in lieu of the load cell board, set to ratiometric operation with 5 Vdc or 10 Vdc excitation — its most sensitive full-scale range is ±200 mV with 10 µV resolution, while the load cell board offers ±20 mV and ±50 mV ranges, both with 1 µV resolution. Transmitters with either board offer 0.01% of full scale ±2 counts accuracy.

Weighing-Specific Display & Setpoint Functions

  • Relay Setpoint Offset — the ON/OFF setpoint control action can be programmed with a specified offset; for example, if bags fill to 100 lbs but the delivery spout dispenses an additional 2.5 lbs after shut-off, an offset of -2.5 lbs can be programmed so the fill valve shuts off at 97.5 lbs measured weight.
  • Count-By Function — the reading can be rounded to multiples of 1, 2, 5, 10, 20, 50, or 100; with count-by 10 selected, the transmitter displays 20 for an internal count of 15 to 24.
  • Fixed Right-Hand Dummy Zero — the display can shift left for a fixed right-hand zero, allowing values up to 999,990, though this precludes decimal point use.
  • Auto-Zero Function — an auto-zero limit from 0 to 9 counts can be programmed to compensate for load cell drift; whenever the reading rests within that limit from zero, it auto-zeros. Entering 0 disables auto-zero.

Two-Point Scale Calibration

Calibration uses a simple two-point method: with no weight on the scale, a button is pushed for LO IN; with a known weight on the scale, the button is pushed again for HI IN. The transmitter automatically computes scale and offset for readout to five digits. Two user-selectable methods provide scale and offset: the coordinate reading method (the transmitter reads actual high/low signal values while the user enters desired high/low readings — ideal with an external calibration reference), or the manual coordinate method (the user enters high/low input values in Volts plus desired high/low readings — suitable without an external reference).

Load Cell Excitation and Wiring

A built-in isolated 10V, 120 mA excitation supply can power up to four 350-ohm load cells in parallel, connected via 4 or 6 wires. With 4-wire connection, the transmitter operates ratiometrically to eliminate errors from power supply variations. With 6-wire connection, it also compensates for lead resistance, allowing long cable runs.

Concurrent Slope™ A-to-D Conversion

The transmitter uses Concurrent Slope™ (US Pat. 5,262,780) analog-to-digital conversion, integrating over a full power line cycle (50 Hz or 60 Hz). A-to-D rate is 60/s at 60 Hz or 50/s at 50 Hz; output update rate is 56/s at 60 Hz or 47/s at 50 Hz; display update rate is 3.5/s at 60 Hz or 3/s at 50 Hz. CMR (DC to 60 Hz) is 130 dB; NMR at 50/60 Hz is 90 dB with minimum filtering. Zero tempco is 0.1 µV/°C — auto-zero is recommended when temperature changes.

Factory-Calibrated Accuracy

All signal conditioner board ranges are factory-calibrated, with calibration factors stored in EEPROM. Field replacement of the signal conditioner board doesn't require recalibrating the transmitter. Factory recalibration is recommended annually.

Where Scale & Weighing DIN Rail Transmitters Are Used

  • Automated Bag & Container Filling — relay setpoint offset compensating for spout dribble after shutoff.
  • Hopper & Batch Weighing — count-by rounding and auto-zero drift compensation for consistent readings.
  • Platform & Vehicle Scales — multi-load-cell weighing with two-point field calibration.
  • Tank & Silo Level-by-Weight Monitoring — fixed right-hand zero for large-capacity displays.
  • Legacy Scale Retrofit — replacing analog indicators with 4-20 mA and serial retransmission.
  • Multi-Point RS485 Weighing Networks — daisy-chained transmitters reporting to a central controller.
  • OEM Weighing Instrumentation — DIN rail integration into existing control panels.

Scale & Weighing DIN Rail Transmitter Frequently Asked Questions

Why would someone choose the DC signal conditioner board over the dedicated load cell board for a weighing application?

Documented specification specifically frames the DC board as usable "in lieu of" the load cell board when set to ratiometric operation — while the load cell board offers more sensitive ranges (±20/±50 mV at 1 µV resolution versus the DC board's ±200 mV at 10 µV resolution), an application whose sensor signal naturally falls in the DC board's less sensitive range could use either board interchangeably, since both are documented as achieving the same 0.01% of full scale ±2 counts accuracy.

Does the relay setpoint offset feature change the underlying weight reading, or only when the relay physically triggers?

Only the relay trigger point — documented example specifically describes the offset as adjusting when the ON/OFF control action occurs (97.5 lbs instead of 100 lbs in the cited example), not altering the actual measured and displayed weight value itself; the displayed reading continues showing the true measured weight while the relay's trigger point is what shifts by the programmed offset.

Why does selecting the fixed right-hand dummy zero preclude using a decimal point?

Documented explanation specifically describes this mode as shifting the display to accommodate a fixed zero digit on the right side, extending the displayable range up to 999,990 — since the display has a fixed total number of digit positions, dedicating one to this fixed right-hand zero uses up the position that would otherwise hold a decimal point, which is why the two features are documented as mutually exclusive.

Does entering 0 for the auto-zero limit disable zero compensation entirely, or just reduce its sensitivity?

Entirely — documented specification specifically states entering 0 disables auto-zero, rather than setting it to a minimal but still-active tracking window; the auto-zero limit ranges from 0 (off) up to 9 counts, with 0 specifically documented as the off state rather than the narrowest active tracking range.

Between the coordinate reading method and the manual coordinate method, does one produce more accurate calibration than the other?

Not inherently — documented guidance specifically frames these as suited to different situations rather than one being more accurate: the coordinate reading method is documented as ideal when an external calibration reference is available (letting the transmitter read actual signal values directly), while the manual coordinate method is documented as suitable specifically when no external reference is available, relying instead on manually entered input values.

Can more than four 350-ohm load cells be connected to a single transmitter by using a higher-current external excitation source?

The page doesn't document this as a supported configuration — the four-cell figure is specifically tied to the transmitter's own built-in 10V, 120 mA excitation supply rating; while the concept of external excitation exists in general load cell system design, this specific transmitter's documented specification describes its own built-in supply as the basis for the four-cell parallel limit, not a higher-capacity external option.

Does the documented 0.1 µV/°C zero tempco mean auto-zero should be run on a fixed schedule, or only when temperature actually changes?

Documented guidance specifically ties the auto-zero recommendation to actual temperature change ("use auto-zero when temperature changes") rather than to a fixed time interval — since the tempco figure describes drift specifically driven by temperature, a stable-temperature environment wouldn't be expected to need auto-zero as frequently as one experiencing genuine temperature swings, making the trigger condition documented as temperature-based rather than schedule-based.

Does the count-by rounding function affect the value transmitted over the analog output and serial data, or only what's shown on the display?

Documented description specifically frames count-by as a display rounding behavior — since the transmitter's analog output and serial data are documented as tracking the underlying measured and scaled reading, the specific interaction between count-by rounding and those output channels isn't detailed as identical to the display in every configuration, making it worth confirming against the actual output value in a given setup if downstream equipment needs to match the rounded display figure exactly.

If both a relay setpoint offset and an auto-zero function are active at the same time, do they interact or interfere with each other?

Not as documented — these two features are described as addressing entirely separate concerns: relay setpoint offset shifts when a control action triggers relative to a target weight, while auto-zero compensates for small drift around the zero point when the reading rests near zero; since one operates around a nonzero setpoint and the other specifically around zero, they're documented as independent functions rather than ones that would typically conflict.

Does the transmitter's documented 0.01% of full scale accuracy apply identically whether it's paired with the load cell board or the DC signal conditioner board?

Yes — documented specification explicitly states transmitters with either board offer 0.01% of full scale ±2 counts accuracy, meaning this accuracy figure is presented as a shared specification across both board options rather than one board being documented as inherently more accurate than the other; the meaningful difference between the two boards is their sensitivity range and resolution, not this stated accuracy figure.

Zero Tracking & Auto-Zero Questions From the Field

What specifically is "zero tracking," and why do most industrial scales include it rather than requiring purely manual zeroing?

Documented explanation specifically describes zero tracking as automatically maintaining the zero indication within a defined limit, compensating for drift caused by internal offset voltage changes, component variation, and environmental factors like temperature — without it, documented guidance notes the zero point would drift noticeably as conditions change, making purely manual zeroing impractical for continuous operation.

Does zero tracking operate continuously regardless of scale activity, or only under specific documented conditions?

Only under specific conditions — documented industrial scale guidance specifically requires the scale be out of motion (commonly defined as no movement for about one second) and within a defined zero tolerance window before zero tracking is permitted to act; tracking is documented as disabled during active motion or when the reading falls outside that tolerance range.

Is there a meaningful tradeoff between setting a wider versus narrower zero tracking window?

Yes — documented guidance specifically frames this as a genuine tradeoff: a wider tracking window (more counts/divisions) gives a more stable zero point less affected by temperature drift, but a narrower window (or disabling tracking) gives more responsiveness to genuinely small applied loads at the cost of a less stable, more drift-prone zero point.

Can zero tracking cause a scale to fail to register a genuinely small but real load placed on it?

Yes, by documented design intent — documented explanation specifically describes this as a deliberate feature rather than a fault: if an added weight falls within the configured tracking window, the scale is documented as "tracking" it and treating it as zero drift rather than a real load, which is why selecting an appropriately narrow window matters for applications needing to detect small load additions.

Does formal weighing-instrument regulation (such as international recommendations for non-automatic weighing instruments) place any specific conditions on when zero tracking is permitted to operate?

Yes — documented regulatory guidance specifically describes zero tracking as permitted to operate only when the indicated value is at or near zero (or the equivalent negative net value at zero gross weight) and the instrument is in a stable, non-moving state — formal regulatory frameworks are documented as placing structured conditions on tracking operation, not leaving it as an unconstrained continuous function.

If a scale's zero tracking function can't be disabled for testing purposes, is there a documented workaround for verifying genuine zero-point accuracy?

Yes — documented field practice specifically describes deliberately applying an additional small load (commonly cited around 10 times the scale's division size) specifically to push the reading beyond the tracking window's range, allowing a technician to observe the instrument's true near-zero accuracy and zero error without the tracking function masking it.

Does frequently triggering auto-zero or tare functions carry any documented downside on instruments that log this activity to internal memory?

Yes, on at least some documented instrument families — documented guidance specifically warns that certain weight controllers save data to internal memory every time zero, tare, or auto-zero functions run, and that very frequent triggering can approach a documented finite write-cycle limit on that memory, with a risk of data corruption at power-up if that limit is reached.

Is manually zeroing the gross weight display subject to the same documented tolerance limits as automatic zero tracking?

Yes, typically — documented guidance specifically notes that a manual zero command (whether via a front-panel button or a communications port command) is commonly limited by the same configured zero tolerance parameter that governs automatic tracking, meaning an operator generally can't manually zero out a reading that falls outside the instrument's documented allowable zero range.