Features
- 20, 50, 100, 250 & 500 mV full scale ranges, 1 microvolt sensitivity
- Accuracy of 0.01% of reading ± 2 counts
- 4- or 6-wire hookup to avoid lead resistance effects
- 10 Vdc excitation to power four 350-ohm load cells in parallel (isolated)
The Laureate™ 1/8 DIN Digital Panel Meter for strain gauge load cell
is a 5-digit panel meter with exceptionally high accuracy and stability for use with low-level signals.- Load cell meter operation provides sensitivity down to ±20 mV full scale for use with 2 mV/V load cells at 10V excitation. Ratiometric operation automatically compensates for changes in excitation. The 5 digit display can be scaled for direct readout in engineering units, such as pounds, kilograms or PSI. Scaling can be via front panel pushbuttons or a computer. Zero may be set from -99,999 to +99,999. Range may be scaled from 0 to ±99,999. Digital scaling and calibration eliminate drift caused by potentiometers in non-microcomputer based meters.
- DC microvoltmeter operation provides sensitivity down to ±20.000 mV full scale with 1 µV resolution for use with 2 mV/V load cells. A display span of 99,999 counts with sensitivity of 0.2 µV per count can be obtained by applying a digital multiplier of five. A moving average digital filter assures quiet readings in electrically noisy environments.
Meter accuracy in ratiometric bridge operation is 0.01% of reading ± 2 counts. Custom curve linearization, which is available with the optional Extended main board, can extend the working range of load cells. Custom curve linearization also allows greater accuracy to be achieved with lower cost, less linear load cells.
A built-in isolated excitation supply can provide up to 120 mA of current at 10V to power four 350-ohm load cells in parallel. The meter operates in a ratiometric mode to eliminate errors due to supply variations. When excitation sense inputs are used in 6-wire connection, the meter compensates for variation in resistance of the transducer leads, thereby 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 digital panel meter. 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 Digital Panel Meters 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 meter for precise operation.
Laureate Digital Panel Meters 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.
Scaling is from -99,999 to +99,999 (five full digits) with any decimal point to display readings in engineering units, such as PSI. Three scaling methods are user selectable: scale and offset, two-point method, and system-level calibration using actual transducer signals.
High read rate of up to 50 or 60 conversions per second, the Laureate™ Digital Panel Meter 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.
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.
Scale and offset can be provided by either of two user-selectable methods:
- With the coordinate reading method, the meter reads the high and low signal values, and the user enters the desired high an low reading values. The meter 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.
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 the front panel or a computer using Laurel's free Instrument Setup Software. For instance, the tare value may be the stated empty weight of a truck or rail car. Pressing the Reset button on the front panel toggles the display between gross weight (total weight on the scale) and net weight (gross weight with tare subtracted).
Peak and valley values are automatically captured. These may be displayed via a front panel pushbutton command or control signal at the rear connector, or be transmitted as serial data.
Two rear panel 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 meter 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.
Load Cell Meter Connections
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.
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.
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 sensitivity in mV/V.
Seat belt tensile strength testing using Laureate digital panel meters.
The three meters display Force, Displacement and Speed.
Modular Design for Maximum Flexibility at Minimum Cost
All boards are isolated from meter and power grounds. Optional Plug-in-Play boards for communications and control include Ethernet, WiFi, serial communication boards, dual or quad relay boards, and an analog output board. Laureates may be powered from 85-264 Vac or optionally from 12-32 Vac or 10-48 Vdc. The display is available with bright red or green 0.56" (14.2mm) high LED digits. The 1/8 DIN case meets NEMA 4X (IP65) specifications from the front when panel mounted. Any setup functions and front panel keys can be locked out for simplified usage and security. A built-in 5, 10, 12, or 24 Vdc excitation supply can power transducers, eliminating the need for an external power supply. All power and signal connections are via UL / VDE / CSA rated screw clamp plugs.
The Laureate™ Series features modular design with up to 7 isolated plug-in boards, applicable to all Laureate 1/8 DIN Digital Panel Meters.
Modular Hardware
The design of the Laureate™ Series is modular for maximum flexibility at minimum cost. All boards are isolated from meter and power grounds. The base configuration for a panel meter or counter consists of a main module (with computer and plug-in display boards), a power supply board, and a signal conditioner board. Optional plug-in-play boards include an isolated setpoint controller board, an isolated analog output board, and an isolated digital interface board. Modular design and a choice of plug-in options allow the Laureate to be customized for a broad range of applications from simple monitoring to control and computer interface. There can be up to five plug-in boards in a 1/8 DIN Laureate.
Connecting Laureate Digital Panel Meters to a Local Area Network (LAN)
Up to 30 Laureate Digital Panel Meters and/or LT Transmitters can be configured for RS485 and daisy-chained to an LT Transmitter using Laurel’s High Speed Ethernet-to-RS485 converter board 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 Digital Panel Meters
Laureate Digital Panel Meters 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.
Load Cell Inputs and DC Microvoltmeter Inputs
| Input Range mV | Resolution | Input Resistance | Error at 25°C |
|---|---|---|---|
| ±20.000 | 1 µV | 1 GΩ | ±0.01% of full scale ±2 counts |
| ±50.000 | 1 µV | ||
| ±100.00 | 10 µV | ||
| ±250.00 | 10 µV | ||
| ±500.00 | 10 µV |
| Full-Scale Input, mV | Zero Adjust | Span Adjust | Input Resistance | Error at 25°C |
|---|---|---|---|---|
| ±20.00 | 0 to ±99,999 | 1 GΩ | ±0.01% of reading ±2 counts |
|
| ±50.00 | -99,999 | |||
| ±100.00 | to | |||
| ±250.00 | +99,999 | |||
| ±500.00 | ||||
| Recalibration: All ranges are calibrated at the factory. Recalibration is recommended every 12 months. | ||||
| Accuracy | |
|---|---|
| Error at 25°C | ±0.01% of reading ± 2 counts in ratiometric mode, ±0.01% of full scale ± 2 counts in absolute mode. |
| Span tempco | 0.0015% of reading/°C |
| Zero tempco | 0.1 µV/°C |
| Load cell linearization | Programmable using Extended meter version |
| 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 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 |
| Display | |
| Readout | 5 LED digits, 7-segment, 14.2 mm (.56"), red or green |
| Range | -99999 to 99999 or -99990 to 99990 (count by 10) |
| Indicators | Minus sign, 2 red LED lamps |
| 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 |
| Power Isolation | 250V rms working, 2.3 kV rms per 1 min 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. |
| Analog Output Board (one optional) | |
| Output levels | 4-20 mA, 0-20 mA, 0-10V, -10 to +10V (jumper selectable) |
| Current compliance | 20 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 | RS232, RS485 with dual RJ11 connectors, RS485 with dual RJ45 connectors, USB, Ethernet, USB-to-RS485 gateway, Ethernet-to-RS485 gateway, WiFi with built-in antenna plus USB & RS485, WiFi with external antenna plus USB & RS485 |
| Protocols | Laurel Custom ASCII (serial), Modbus RTU (serial), Modbus TCP (Ethernet or WiFi) |
| Digital addresses | 247 (Modbus), 31 (Laurel ASCII), |
| Isolation | 250V rms working, 2.3 kV rms per 1 min test |
| Signal Connections | |
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|
| 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) |
| 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, the 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. | |
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.
Laureate™ 1/8 DIN Case For Laureate Digital Panel Meters, Counters, Timers & Remote Displays
Key Features
- Meets 1/8 DIN Standard.
- Installs from front of panel.
- Short depth behind the panel: only 4" (102 mm) plus connectors.
- Understated 0.157" (4 mm) thick bezel.
- Meets NEMA 4X (IP-65) for high-pressure wawshdon when panel mounted.
- Screw clamps connectors meet VDE / IEC / UL / CSA safety standards.
- Rugged GE Lexan® housing material.
- Safety certified per EN 61010-1.
Dimensions
Maximum panel thickness: 4.5 mm (0.18")
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)
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)
Dimensioned CAD assembly drawings in EPRT, STEP, x_t. dwg, pdf file formats: Laureate-meter-case.zip (zipping prevents browser from opening CAD files as text files).
Panel Mounting
Slide the meter into a 45 x 92 mm 1/8 DIN panel cutout. Ensure that the provided gasket is in place between the front of the panel and the back of the meter bezel.
The meter is secured by two pawls, each held by a screw, as illustrated. Turning each screw counterclockwise extends the pawl outward from the case and behind the panel. Turning each screw clockwise further tightens it against the panel to secure the meter.
Turning each screw counterclockwise loosens the pawl and retracts it into its well. This position allows installed meter to be removed from their panel, or new meters to be installed in a panel. Do not remove the screws from their pawls. Doing so would cause the screw and pawl to fall off and likely get lost. Do not overtighten so as not to damage the plastic parts.
Load Cell Meter Frequently Asked Technical Questions
Yes, they do. The Signal inputs of the load cell meter must receive the millivolt signal outputs of the load cell. At 10V excitation, these can range from -20 mV to +20 mV for a 2 mV/V load cell or -30 mV to +30 mV for a 3 mV/V load cell. The Signal is what is converted by the meter into a reading in engineering units like pounds or PSI. The Sense inputs of the meter must sense the excitation voltage, which is also used as the reference for the meter's analog-to-digital converter. With a 6-wire load cell connection, the excitation voltage should be sensed at the load cell after any voltage drop due to resistance of the excitation leads. With a 4-wire load cell connection, the excitation voltage can be sensed at the meter by connecting +Sense to +Excitation and -Sense to -Excitation, but the sensed voltage will then higher than the actual voltage applied to the load cell.
Load cell meter scaling is the process of converting input millivolts to a reading in engineering units. For example, meter scaling is the process of converting the 0-20.000 mV DC output of a load cell to a 0-5000 lb weight reading on the meter.
A count is a unit of resolution. For the Laureate ±20.000 mV and ±50.000 mV ranges, each input count is 0.001 mV (or 1 microvolt) of resolution. For example, 17.354 mV is 17354 input counts. Display counts are the values to be displayed as readings. For example, a reading of 2465.7 lbs is 24657 display counts. The decimal point is set separately as a decoration.
Simply enter data from the load cell label. For example, the label may state 10V excitation, a load rating of 5000 lbs, and 2.020 mV per volt sensitivity. This means 0 mV should be displayed as 0 lbs, and 20.20 mV should be displayed as 5000. To enter this data into the meter, go to the front panel menu item “SEtuP” and select “Coordinates of 2 points method.” Enter Lo In as 0.000 mV, Hi In as 20.200 mV, Lo Read as 0 lbs, and Hi Read as 5000 lbs.
First zero the scale and meter as a system by not applying any weight, then weigh a known, calibrated weight and enter that value into the meter. To do so, go to the front panel menu item “SEtuP” and select “Reading coordinates of 2 points method.” The meter will then prompt you to measure Lo In and High In, and to enter values for Lo Read and High Read.
The ordering process for a Laureate load cell / microvolt meter requires that min input, min reading and max input, max reading be specified at the time of order. This information allows Laurel to set the meter range, which can be ±20.000 mV, ±50.000 mV, ±100.00 mV, ±250.00 mV, or ±500.00 mV, and to scale the meter using the coordinates of 2 points method. This initial setup can easily be changed by the user by moving jumpers and changing scaling via the meter’s front panel, as explained in Section 19 of the Laureate DPM user manual.
The + and - signal inputs measure the millivolt output of the load cell, while the + and - sense inputs measure the excitation voltage that is applied to the load cell. The sensed voltage is used as the reference to the meter’s analog-to-digital converter. If possible, the excitation voltage should be sensed at the load cell, not at the meter, so that it is measured after any voltage drop through the excitation wires. If these wires are long, this voltage drop can be substantial. For example, if the excitation and excitation return wires each have a resistance of 1 ohm, the voltage drop will be V = IR = (10V / 350 ohm) * 2 ohm = 0.057V, so that the actual voltage applied to the load cell is 10V – 0.057V = 9.94V.
Laureate load cell meters are modular with slots for an analog output board, a choice of relay boards, and a choice of communication boards, as illustrated in our Laureates Overview web page. These boards can be ordered installed with a new meter, but they can also be purchased separately later and be simply plugged in. The presence of a new board and the type of board are automatically sensed by the meter’s firmware or by Instrument Setup (IS) software. If you change boards, also change the model number on the meter label.
The Laureate load cell meter offers resolution down to 1 microvolt per count, while the Laureate process meter is limited to 10 microvolts per count. The load cell meter can also be set up for a 6-wire connection, while the process meter is limited to 4 wires. The extra 2 wires are used to eliminate errors due to voltage drops in long cable runs. Both types of meters can be used with the same types of load cells and can scale millivolt signals for display in engineering units. The slightly more expensive load cell meter is recommended for more demanding applications.
The Laureate load cell meter and microvolt meter are the same meter, but they are set up differently. In load cell mode, the meter works in a ratiometric bridge mode, where the applied voltage excitation is also used as the reference for the analog-to-digital converter. This automatically corrects for any variations in excitation voltage. In microvolt meter mode, the meter is calibrated to NIST standards for absolute readings in millivolts or microvolts.
The hardware of the load cell meter and scale meter is the same, but the meter firmware is slightly different, as detailed in the Scale Meter for Weighing Applications web page. Compared to the standard load cell meter, the scale meter offers five extra user selectable functions specifically for weighing applications:
1) Relay setpoint offset,
2) Count-by function,
3) Fixed right-hand dummy zero,
4) Auto-zero function,
5) Manual tare function.
1) Relay setpoint offset,
2) Count-by function,
3) Fixed right-hand dummy zero,
4) Auto-zero function,
5) Manual tare function.
Yes. A summing box is simply a clean way to connect the meter to the 6 wires of multiple load cells in parallel. Up to four linear load cells of the same type can be connected in parallel and be powered by the same 10 Vdc, 120 mA excitation output of a Laureate meter. For example, four load cells can be used to support the four corners of a weighing platform. Each 350 ohm load cell will draw an I=V/R current of 28.6 mA, so that the total current requiremet for four load cells is 114.4 mA. For scaling purposes, multiply the weight read by each load cell by the number of load cells, since each load cell only carries part of the load. The best way scale a system with multiple load cells is to use the "Reading Coordinates of 2 Points" scaling method, which uses actual weights.
Input calibration is the process of adjusting the load cell /microvolt meter in software so that absolute readings in millivolts or microvolts are within specified tolerances of a recognized national standard. Input calibration is required for microvolt meter mode and for load cell meter setup using the scale and offset scaling method or the coordinates of 2 points scaling method. Input calibration is not required for the reading coordinates of 2 points scaling methods, which uses actual weights for calibration, not known electrical signals. Note that the Laureate load cell / microvolt meter comes with five factory calibrated voltage ranges with calibration factors stored in EEPROM on the load cell signal conditioner board: ±20.000 mV, ±50.000 mV, ±100.00 mV, ±250.00 mV, ±500.00 mV.
Annual calibration to NIST standards can be performed by Laurel and by some of its distributors as a service. It can also be performed by the customer using Laurel’s free Windows based Instrument Setup (IS) software. Open the Main Menu of IS software, click on Calibration in the top menu bar, and follow the prompts. An external DC voltage standard is required. Also required in the meter is a communications board, like the Laureate P/N LUSB USB interface board. Following calibration, that board can be removed and be used in another meter.
Analog output scaling is the process of converting the meter reading to an analog output, which can be user selected as 4-20 mA, 0-20 mA, 0-10V or -10 to +10V. Simply enter the load cell meter readings for the bottom and tops of the selected analog output range, and the output will be interpolated linearly between these two readings. Please see Section 17 of the Laureate DPM user manual.
Chances are that your meter is set for the factory default analog output, which is 4-20 mA, and is applying around 12V to force a current into an open circuit. To set your meter to a 0-10V or -10 to +10V analog output, set jumpers for unipolar 0-10V or bipolar -10 to +10V operation, select the desired range and scaling, and connect to the correct analog output pins, as explained in Section 17 of the Laureate DPM user manual.
Auto-Tare
To read the net weight of an object, the empty container is first weighed, and an external button is pushed to zero out the display. The meter will then read net weight when an object is added to the empty container. The tare value is stored in memory for subsequent readings.
To read the net weight of an object, the empty container is first weighed, and an external button is pushed to zero out the display. The meter will then read net weight when an object is added to the empty container. The tare value is stored in memory for subsequent readings.
Determining Volume Using Load Cells
An easy way to determine volume of an irregularly shaped tank with no need for linearizing is to weigh the tank using load cells. The meter will automatically tare out the weight of the empty tank and then scale the load cell signals to units of volume, such as liters or gallons.
An easy way to determine volume of an irregularly shaped tank with no need for linearizing is to weigh the tank using load cells. The meter will automatically tare out the weight of the empty tank and then scale the load cell signals to units of volume, such as liters or gallons.
Capture for Tensile Strength of Wire
Peak readings are automatically captured at rates up to 60 per second, while the display updates at a legible 3.5 per second. The peak reading can be recalled at the push of a button or be always displayed. It can also be transmitted to a computer via RS232, RS485, USB or Ethernet.
Peak readings are automatically captured at rates up to 60 per second, while the display updates at a legible 3.5 per second. The peak reading can be recalled at the push of a button or be always displayed. It can also be transmitted to a computer via RS232, RS485, USB or Ethernet.
IPC
Splashproof Cover
IPC
$48.00
CLB01
RS232 Cable for Meters
CBL01
$35.00
CLB02
USB-to-RS232 Adapter Cable
CBL02
$47.00
CBL04
RS232 Cable for LT Transmitters
CBL04
$47.00
CLB05
USB Data Cable for Meters
CBL05
$47.00
CLB06
USB-to-RS485 Adapter Cable
CBL06
$47.00
CLB07
USB Programming & Data Cable
CBL07
$47.00
CLB08
RS485 Splitter Cable
CBL08
$33.00
BKBD
RS485 RJ11 Terminal Block Adapter
BKBD
$47.00
