RAPG Single Point Load Cell
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.
RAPG Single Point Load Cell Quick Links
Highlights
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Capacities
The RAPG series is available in 100 g, 300 g, 1 kg, 2 kg, 3 kg capacities. See RAP4 for 50 kg (110 lb) & 250 kg (550 lb) capacities. See RSP1/RSP2 for higher capacities. 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 scale platforms and force measurement applications in dehydration chambers, wind tunnels etc.
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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 SmartPhonesAnalog Output
Analog output via 0-5V DC or 4-20 mA output for easy input to DAQ or PLCCustomize
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.
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.
You can make a larger scale using four load cells as shown in this assembly using simple beams as a base and a plate on top. You can use our DI-400U device to build a USB scale with multiple load cells.
You can make a larger scale using four load cells as shown in this assembly using simple beams as a base and a plate on top. You could have a plate as a base instead as well. Add a DI-400U and presto you get a USB scale!
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.
Kit Includes:
RAPG 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.
Kit Includes:
RAPG 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
Kit Includes:
Four RAP3 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.
Kit Includes:
Four RAPG 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.
Kit Includes:
RAPG 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).
Kit Includes:
Four RAPG 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.
Kit Includes:
RAPG 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.
Kit Includes:
RAPG 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.
- How to Write Software to Work with DI-1000U / DI-1000UHS / DI-1000UHS-1K
- How to Write Software to Work with DI-100U / DI-100UHS / DI-400U / DI-400UHS
- How to Write Software to Work with iLoad / iLoad Pro / iLoad Mini / iLoad Mini Pro
You can access Sample Code for Visual Basic, Matlab, Python, Arduino and customize it for your own needs.
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 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". The RRP2 is an NTEP rated version of a load cell similar to RAP3/RAP4 but for trade applications. The RAPG is one of the load cells with the smalles capacities with the highest accuracy in the sub gram range. There really is not much of an alternative if that is what you are trying to do.
RAP4
Identical to RAP3, Low Profile
Capacity: 50 kg (110 lb), 250 (550 lb), 300 kg (660 lb)
Accuracy Class: 0.02% of full scale
Comp. Temp Range: -10C to 40C
RRP2
NTEP Rated Load Cell
Capacities: Up to 660 kg
Accuracy Class: 0.02% of full scale
Comp. Temp Range: -10C to 40C
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
RAP3
Excellent for Off-Center Loading
Capacities: 750 kg
Accuracy Class: 0.02% of full scale
Comp. Temp Range: -10C to 40C
Watch and Learn
FAQ
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.
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.
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.
The RSP1 load cell and RAPG load cells are almost identical in design except for the fact that the RAPG is much smaller in size and is offered in capacities as low as 100 grams. If you need to measure loads in sub gram accuracy then the RAPG is the load cell for you!
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.
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.
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!
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.
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.
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!
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.
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