EVAL-CN0216-ARDZ

One Technology Way · P.O. Box 9106 · Norwood, MA 02062-9106 · Tel: 781.329.4700 · Fax: 781.461.3113 · www.analog.com CN0216 Shield Evaluation Board User Guide Overview CN-0216 is a precision weigh scale signal conditioning system. It uses the AD7791, a low power buffered 24-bit sigma-delta ADC along with dual external ADA4528-2 zero-drift amplifiers. This solution allows for high dc gain with a single supply. Ultralow noise, low offset voltage, and low drift amplifiers are used at the front end for amplification of the low-level signal from the load cell. The circuit yields 15.3 bit noise-free code resolution for a load cell with a full-scale output of 10 mV. This circuit allows great flexibility in designing a custom low-level signal conditioning front end that gives the user the ability to easily optimize the overall transfer function of the combined sensor-amplifier-converter circuit. The AD7791 maintains good performance over the complete output data range, from 9.5 Hz to 120 Hz, which allows it to be used in weigh scale applications that operate at various low speeds. The EVAL-CN0216-ARDZ evaluation board is compatible with the Arduino Shield form factor. This user guide will discuss how to use the evaluation software to collect data from the EVAL-CN0216-ARDZ Evaluation Board (CN-0216 Board) Required Equipment ● ● ● ● ● EVAL-CN0216-ARDZ Evaluation Board Arduino Processor Board (Uno/Mega 2560/Leonardo or Similar) LINX Firmware loaded on the Arduino CN0216 Shield Evaluation Software PC with the following Minimum Requirements Windows Vista/7 (32-bit) USB type A Port Processor rated at 1GHz or faster 1GB RAM and 500 MB available hard disk space Tedea Huntleigh Model 1042 Load Cell ❍ ❍ ❍ ❍ ● NOTE - Any 4 or 6 wire load cells can be used with the Rev 21 Oct 2014 03:11 | Page 1 CN-0216 Board. This guide was written with the Tedeah Huntleigh Model 1042 in mind. General Setup ● ● ● ● The EVAL-CN0216-ARDZ (CN-0216 Shield Board) connects to a Shield form factor Arduino Board Power the system through the Arduino using an external wall wart(7V-12V recommended) for best performance Connect the system to the PC using a USB cable The Tedeah Huntleigh Model 1042 load cell connects to the EVAL-CN0216-ARDZ via the 8 pin header Jumper Settings ● “0” Position (shown below) P2 - Connects REFIN+ to Sensor +Sense pin P3 - Connects REFIN- to Sensor -Sense pin ❍ ❍ Rev 21 Oct 2014 03:11 | Page 2 ● “1” Position P2 - Connects REFIN+ to 5V supply P3 - Connects REFIN- to GND ❍ ❍ Installing the Software 1. Extract the file CN0216 Eval Software.zip and open the file setup.exe. NOTE: It is recommended that you install the CN0216 Shield Evaluation Software to the default directory path C:\Program Files\Analog Devices\ and all National Instruments products to C:\Program Files\National Instruments\ Rev 21 Oct 2014 03:11 | Page 3 2. Click Next to view the installation review page Rev 21 Oct 2014 03:11 | Page 4 3. Click Next to start the installation 4. Click Finish to complete the installation. Please make sure Arduino USB drivers are installed and your Arduino processor board is flashed with the latest LINX Firmware Connecting the Hardware 1. Connect the Tedeah-Huntleigh (Model 1042) Load Cell to 8-pin header of the EVAL-CN0216-ARDZ (CN-0216 Board) as depicted below. NOTE: If a different Load Cell is used other than the Tedeah-Huntleigh Model 1042, the wiring schematic will be different! Rev 21 Oct 2014 03:11 | Page 5 Using the Evaluation Software Software Controls and Indicators Description Rev 21 Oct 2014 03:11 | Page 6 Rev 21 Oct 2014 03:11 | Page 7 1. Run When this button is pressed, the system start collecting ADC Data and presents it in the display and chart 2. Stop When this button is pressed, the systems stops/pauses data acquisiton 3. Clear Chart When this button is pressed, data in the chart is cleared/erased 4. Save Data When this button is pressed, it opens a prompt to allow the user to save data to a spreadsheet 5. Calibration Weight Allows the user to specify the calibration weight used(in grams) 6. Calibrate When this button is pressed, it will start the calibration process and give the user instructions on how to proceed 7. ADC Mode Radio Buttons This control is used to set the mode of the AD7791. The default value is Unbuffered Mode and is ❍ ❍ ❍ ❍ ❍ ❍ ❍ Rev 21 Oct 2014 03:11 | Page 8 highlighted in bold on the Calibrate System Tab. Buffered Mode - Selecting this mode turns the on-chip analog input channel buffer of the AD7791 ON. Unbuffered Mode - Selecting this radio button turns the on-chip analog input channel buffer of the AD7791 OFF. ADC Channel Select Radio Buttons This control is used to select the analog input channel of the AD7791 for conversion. The default value is AIN(+)-AIN(-) and is highlighted in bold on the Calibrate System Tab. AIN(+)-AIN(-) - Selecting this radio button allows for normal operation of the AD7791. AIN(-)-AIN(-) - Selecting this radio button shorts the analog input channels of the AD7791. Vdd Monitor - Selecting this radio button monitors the voltage applied to the Vdd pin of the AD7791. The voltage is attenuated by 5 and the resultant voltage is applied to the ∑-Δ modulator using an internal 1.17 V reference for analog to digital conversion. Update Rate Radio Buttons This control is used to change the output word rate of the AD7791. The default value is 9.5 Hz and is highlighted in bold on the Calibrate System Tab. Configure ADC Button When this button is pressed the current value of the ADC Mode Radio Buttons, ADC Channel Select Radio Buttons, and Update Rate Radio Buttons are used to configure the AD7791. System Status String Indicator This indicator displays a message to the user detailing the current state of the software. System Status LED Indicator This indicator displays the current state of the software in the form of an LED. There are three status LED colors. Inactive Busy Error Current Weight Numerical Indicator This indicator displays the mass (in grams) on the load cell. Weight/Code Chart This indicator displays the data in chart form. Chart Controls These controls allow the user to zoom-in, zoom-out, and pan through the data collected. Select Units Radio Buttons This control determines the Y-Axis units of the data displayed in the chart. ■ ■ 8. ❍ ■ ■ ■ 9. ❍ 10. ❍ 11. ❍ 12. ❍ 13. ❍ 14. ❍ 15. ❍ 16. ❍ More Information ● ● ● ● ● ● CN-0216 Webpage CN0216 Shield Evaluation Software AD7791 Product Page ADA4528-2 Product Page Arduino Official Website LINX Firmware Download Rev 21 Oct 2014 03:11 | Page 9 © Analog Devices, Inc. All rights reserved. Trademarks and registered trademarks are the property of their respective owners. Rev 21 Oct 2014 03:11 | Page 10 www.analog.com