RAP4 Single Point Load Cell

These single point load cells are some of the most accurate and versatile load cells we offer at very reasonable prices. They are ideal for building scales because of their unique ability to withstand off axis and off center loading. They are also temperature compensated from -10C to 40C and offer accuracies of +/- 0.02% of full scale. The RAP4 load cells are low profile and are available in 50 kg, 250 kg and 300 kg capacities. The RAP3 is larger in height and is available in 750 kg capacity. For smaller capacities and smaller sizes take a look at the RSP1 and RAPG load cells. For NTEP rated versions take a look at the RRP1 and RRP2 load cells.

You can buy just the Load Cells or buy the Load Cells with interface devices such as analog signal conditioners, digital USB or wireless load cell interfaces, displays and software as complete ready to use kits.

Highlights

  • Capacities
    RAP4 Single Point load cells are available in 50 kg, 250 kg, and 300 kg capacities. See RAP3 for 750 kg capacity. See RSP1/RAPG for lower capacities and smaller sizes. See RRP1/RRP2 for NTEP rated load cells.

  • Calibration Mode
    Single Point load cells can be used for Compression, Tension or Universal (both Compressions and Tension) measurements. 

  • Accuracy Class & Compensated Temperature Range
    +/- 0.02% to +/- 0.05% of full scale from -10C to 40C

  • Construction and Use
    Excellent off-center loading compensation hence ideal for larger scale platforms such as tote scales, pallet scales, tank weighing, hopper weighing and floor scales

  • UART/USB Output
    Use DI-100U with UART output to connect with Arduino or other microprocessors. Or use DI-100U/DI-1000U/DI-400U USB load cell interfaces to connect with PCs via USB.

    Wireless Output
    Wireless output via XBee (802.15.4) Industrial Strength wireless or WiFi or BLE for easy connectivity with PCs, Tablets and SmartPhones

    Analog Output
    Analog output via 0-5V DC or 4-20 mA output for easy input to DAQ or PLC

    Customize
    Call us for larger capacities or other unique needs. We can custom build them to order as needed.

Mounting Options

Single Point load cells can be imagined to work like a diving board. One end of the load cell has to be held firmly to a fixed surface. Threaded holes one each end can be used to fasten the load cell to the fixed surface on one end and the load has to be applied to the other end. In order to get clearance for the load cell to bend and give a little, spacers are used as needed to create the clearance under the load cell. The load cell can be used in any orientation and can be used in tension or compression or both modes.

RAP4 Single Point Load Cell
RAP4 Single Point Load Cell
RAP4 Single Point Load Cell
RAP4 Single Point Load Cell

One end of the load cell needs to be fixed and the load applied to the other end. The load cell can be fastened using the threaded holes on each end. Spacers are used to provide a gap for the load cell to deflect in response to the applied load.

These load cells have off center loading compensation and therefore perfect for scales. The bottom of the load cell is fixed to a base and the platform is fixed to the top of the load cell as shown. The spacers help to concentrate the loads.

You don't necessarily need plates on each end to use the load cell. You can simply apply the load to the rectangular area on one end where  there are mounting holes. Fix the other end as shown. In this assembly you do not need to use spacers.

This sub assembly shows how one can build a weigh module with a base and a top. One can add other features to the plates as needed. The sub assembly is constructed using a RAP4/RAP3 load cell with spacers and 8" x 8" one 1" thick plates.

Load Cell Configurations

Single Point Load Cells are based on the classic wheatstone balanced bridge network design using strain gages. The baseline output is mV/V i.e. if you supply say 10V to the sensor, then the output voltage may vary from 0 mV to 20 mV for a 2 mV/V device. They can be mated and used with digital or analog signal conditioners (digital or analog interfaces) to connect with PCs, PLCs, or simple LCD diplays. We offer the following options:

USB Load Cell with DI-1000U Configuration

If you need to do testing and data gathering or want to display values on a PC/Tablet via USB, simply connect the load cell to the DI-1000U Digital Load Cell Interface & use the USB connector on the DI-1000 to connect to a PC via the USB port. The DI-1000U is a signal conditioner & 24-bit digitizer (good enough to handle load cells with 0.02% of full scale accuracy) and handles all the communications functions to talk with USB port of a PC.  When connected this way, the load cell appears on the PC as a virtual COM port. Using a standard terminal emulator you can send commands to the sensor to display loads on screen. They can be displayed either one reading at a time or in continuous operation mode. You can also use Matlab, LabView or other popular programs to communicate and get calibrated readings from the load cell. It would be best if used our LoadVUE Pro application to display, log or plot data on a PC.

RAP4 Single Point Digital Load Cell with 24 Bit USB Output DI-1000U and Software LV-1000
Kit Includes:


RAP4 Single Point Load Cell
DI-1000U Load Cell Interface
LV-1000 LoadVUE Pro Software
Add Calibration
Add Accessories

USB Load Cell with DI-100U Configuration

If you do not need the very high precision of the DI-1000U, you can use our DI-100U digital load cell interface with 16 bit ADCs and Serial TTL or USB output.  The DI-100U is sufficient for accuracies of +/- 0.1% of full scale output.  Or in other words if you need to measure +/- 1 lb accuracy over 1000 lb range or +/- 0.1 lb accuracy over 100 lb range, then the DI-100U is more than adequate for your application. If you wish to connect a load cell with an Arduino or other microprocessors or microcontrollers, then you can disconnect the S2U Serial to USB converter adapter and directly communicate via UART. 

RAP4 Single Point Digital Load Cell with 16 Bit USB Output DI-100U and Software LV-1000
Kit Includes:


RAP4 Single Point Load Cell
DI-100U Load Cell Interface
LV-1000 LoadVUE Pro Software
Add Calibration
Add Accessories

16 Bit Four Sensor USB Kit

A lower priced version of the above 4 sensor kit is also available with a DI-400U 4 channel USB load cell interface

RAP4 Single Point Digital Load Cell Four Sensor Kit with USB Output DI-400U and Software SensorVUE
Kit Includes:


Four RAP4 Single Point Load Cells
DI-400U 4 Channel USB Interface
SensorVUE Software
Add Calibration
Add Accessories

24 Bit Four Sensor USB Kit

Sometimes you need multiple load cells to measure the forces acting at multiple points. In those cases you may want to use this four load cell kit with a DI-400U Four Channel USB Interface and SensorVUE software to display, log and plot data on Windows PC or Tablet.

RAP4 Single Point Digital Load Cell Four Sensor Kit with 24 Bit USB Output DI-1000U and Software SensorVUE
Kit Includes:


Four RAP4 Single Point Load Cells
Four DI-1000U USB Interface
SensorVUE Software
Add Calibration
Add Accessories

USB Load Cell with LCD Display

If you don't want to use a PC or PLC and just want a simple LCD display, you can use our DS-3000-Pro Touch Screen LCD Display. The load cell needs to be mated with a DI-100U or DI-1000U and calibrated together as a pair. This pair can be used with the display or with a PC or tablet. This it gives you a load cell, a DI-1000U USB Interface, LoadVUE Pro software (to use with a PC to display, log and plot data and recalibrate if needed) plus a Touch Screen Single Channel Display if all you need to do is just use for operations for a quick display.

RAP4 Single Point Digital Load Cell with 24 Bit USB Output DI-1000U and Digital LCD Display DS-3000-Pro-1 Channel
Kit Includes:


RAP4 Single Point Load Cell
DI-1000U or DI-100U USB Interface
DS-3000-Pro-1 Touch Screen Display
LoadVUE Pro Software
Add Calibration
Add Accessories

USB Load Cell with 4-Channel LCD Display

When you want to display values from multiple load cells on a LCD Display, then use our DS-3000-Pro-4 device as shown below. The DI-400U Four Channel USB Interface connects to four load cells. You can use SensorVUE software to display, log and plot data or just use the DS-3000-Pro-4 display to show individual as well as total load on all connected sensors (up to four).

Four RAP4 Single Point Digital Load Cells with 24 Bit USB Output DI-1000U and Digital LCD Display DS-3000-Pro-4 Channel
Kit Includes:


Four RAP4 Single Point Load Cells
DI-400U USB Interface
DS-3000-Pro-4 Touch Screen Display
SensorVUE Software
Add Calibration
Add Accessories

Wireless Load Cell Configuration

You can use this load cell wirelessly by connecting it to our DI-1000ZP wireless load cell interface. This configuration allows you to wirelessly connect to a Windows/Unix/Mac computer. On a Windows platform, you can use our LV-1000 LoadVUE Pro software to display, log and plot force vs time data effortlessly. The DI-1000ZP uses the 802.15.4 protocol and offers robust connectivity to about 1000 feet in industrial environments. It comes with a battery backup for cordless operation for a couple of hours. If you wish to connect via WiFi or BLE we offer the DI-1000WiFi and DI-1000BLE that makes it easy to communicate with Smartphones as well.

RAP4 Single Point Digital Load Cell with Wireless Output DI-1000ZP DI-1000BLE DI-1000WiFi and Software LV-1000
Kit Includes:


RAP4 Single Point Load Cell
DI-100U Load Cell Interface
LV-1000 LoadVUE Pro Software
Add Calibration
Add Accessories

Analog Load Cell Configuration

Some users want a high level 0-5V analog DC output in order to work with existing data acquisition systems or PLCs. Ih that case, you can use this load cell with our AI-1000 Load Cell interface which provides an amplified 0.5 to 4.5V output proportional to the applied loads. We can provide the system together with calibration and the formula to convert from voltage to loads/forces when ordered in this configuration. We also offer the AI-1000-CV with 4-20 mA output if you prefer current output. Please contact us for this kit.

RAP4 Single Point Digital Load Cell with Analog Output to Connect to PLC and DAQ
Kit Includes:


RAP4 Single Point Load Cell
AI-1000 Analog Load Cell Interface
Add Calibration
Add Accessories

Application Development

If you are looking to develop your own custom software application, our digital USB load cells and wireless load cell interfaces offer convenient ASCII commands to obtain load information directly from the interfaces/load cells without need for any signal conditioning or data processing. With just a few commands you'll be able to incorporate load/force/weight information into your application. You can also use Visual Basic, Visual C++, Matlab, LABView or any other application development environment to create your custom applications with our interface/load cells.

See our support pages for details.

You can access Sample Code for Visual Basic, Matlab, Python, Arduino and customize it for your own needs.

Downloads

Register on our site and download the Spec-sheets and Solid Models for RAS1.

Spec-sheets
Spec-sheets

Download Technical Specifications

Download
Solid Models
Solid Models

Download Solid Models

Download

Alternative Load Cells

We offer a range of Single Point Load Cells to build different scales. Some have just two mounting holes and others have four load cells for a a much more robust fastening scheme for heavier loads.  The RRP2 is an NTEP rated version of a load cell similar to RAP3/RAP4 but for trade applications. The RAPG is for high accuracy at very low loads (100 grams, 300 grams, 1 kg, 2 kg, 3 kg) and scale sizes say up to 6" x 6" in size and are the smallest single point load cell we offer. The RSP1 load cells have a size smaller than RAP3/RAP4 but larger than RAPGs and are for 3 kg to 50 kg load measurements and can handle scales sizes of up to 12" x 12".

RAP3
RAP3

Identical to RAP4 but twice as high
Capacity: 750 kg (1650 lb)
Accuracy Class: 0.02% of full scale
Comp. Temp Range: -10C to 40C

Explore
RRP2
RRP2

NTEP Rated Load Cell
Capacities: Up to 660 kg
Accuracy Class: 0.02% of full scale
Comp. Temp Range: -10C to 40C

Explore
RSP1
RSP1

Smaller with two mounting holes
Capacities: 5 kg to 150 kg
Accuracy Class: 0.02% of full scale
Comp. Temp Range: -10C to 40C

Explore
RAPG
RAPG

Low Capacity Small Size Load Cell
Capacities: 100 g to 3 kg
Accuracy Class: 0.02% of full scale
Comp. Temp Range: -10C to 40C

Explore

Watch and Learn

FAQ

Why is it called a Single Point Load Cell?

It is called a single point load cell because all the forces and moments are concentrated at a single point onto the load cell and accounts for it successfully to provide an accurate measurement of the applied force.

What is unique about the Single Point Load Cell?

Single Point load cells are designed specially for making scales. They have excellent sensitivity, accuracy and thermal stability over a wide range of temperatures from -10C to 40C. But most importantly they are able to compensate for off center loading so the weights can be placed anywhere over a certain area without compromising accuracy.

What technology is used to make the RAP4?

The single point load cell is a resisitive load cell device. It is built using strain gauges arranged in a wheatstone bridge network. A strain gauge is basically a resistive element that is piezo resistive i.e. it changes resistance in response to changes in strain (change in length over original length). Applied forces lead to induced stresses that lead to displacement and strain. The change in strain leads to a change in resistance. So with an applied inout voltage one can measure tiny changes in voltage and use this to infer the applied force.

What's the difference between RAP4 and RAP3?

The RAP3 and RAP4 load cells are identical in almost every respect except one - their height. The RAP3 is available only in 750 kg capacity and is twice as high as the RAP4. The mounting hole size and location are identical. We use the RAP3 load cell for our PunchSensor boxing training kit.

Which of these load cells are NTEP rated?

NTEP is standard set by the US Dept. of Commerce for weighing systems used for trade to sell products by weight. If you sell say coffee beans by the lb then you are supposed to use an NTEP rated scale (and hence an NTEP rated load cell). The RRP1, RRP2 are NTEP rated single point load cells.

What interface devices are compatible with the RAP4?

We offer signal conditioners that allow you to connect to a computer (PC. Mac or Linux) via USB (DI-100U or DI-1000U) or wirelessly via XBee, WiFi or BLE protocols (DI-1000ZP/DI-1000WiFi/DI-1000BLE).
We also offer sensor interfaces with UART output (DI-100U) to connect to a microcontroller to develop an embedded application. Our analog signal conditioner (AI-1000 and AI-1000-CV) make it easy to get  analog 0-5 V voltage output or 4-20 mA current output. Or simply connect to our touch screen LCD display to show values on a simple physical display.

What load cell software do you offer?

We offer free LoadVUE Lite software to display force/weight on a Windows 8/10 PC/Tablet. The LoadVUE Pro software allows you to display, log & plot force/weight data, recalibrate sensors and get remote support. SensorVUE extends support to an unlimited number of sensors as well as all types of sensors we offer. ControlVUE software extends the functionality offered by SensorVUE and adds the ability to control external devices based on sensor values through a USB Relay with one to eight channel. Our sensors and interfaces allow you to write your own code as well! We also offer customization and custom softrware development services to meet your specific needs!

Do you offer calibration service?

Yes. We offer calibration service on new sensor purchases as well as recalibration service for previously purchased sensors. We use NIST traceable reference standards to perform and validate the calibration and provide a free calibration certificate as part of the service. We are NOT ISO certified.

How can I get pricing information?

You can register on our website, login and see all prices, download spec sheets and solid models. You can also send us an email with your contact information and shipping address and we will be happy to send you a formal quote.

What is your return policy?

We give you a 30 day guiarantee for you purchase. You can exchange or return your purchased products for a refund of the purchase price of the product. Any calibration service fees, shipping and payment fees cannot be refunded. Feel free to try out our products risk free and see for yourself how easy we make it for you!

What is the typical lead time?

We need between one and two weeks usually to ship your order for items in stock. This is because we have to make your sensor, interface and calibrate them together, make sure the quality meets all specs and then pack and ship it to you. We offer expedited processing options if you are in a rush and need to get sensors sooner. If out of stock or if sensors are needed in volume, we could take 4-6 weeks or longer. Please contact us to get an estimate of price and lead time for your particular needs.

Do you offer educational discount?

We believe teaching young kids and encouraging R&D is crucial to make this world a better place. We support teaching and research activities in educational institutions with a 10% education discount on purchased products in exchange for sharing write ups, pictures, video clips and other material we can use in our marketing materials on and off line.

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