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.
|Pin Number||Pin Function|
|Pin 1||Not Used|
|Pin 2||- Excitation|
|Pin 3||+ Signal|
|Pin 4||- Sense|
|Pin 5||+ Sense|
|Pin 6||- Signal|
|Pin 7||+ Excitation|
|Pin 8||Not Used|
These set of jumpers allow the circuit to be configured for use with 4-wire or 6-wire load cells.
NOTE - Any 4 or 6 wire load cells can be used with the EVAL-CN0216-ARDZ.
The Tedeah Huntleigh Model 1042 load cell was used during testing.
Place jumpers/shunts as shown above for 6-wire resistive bridge configuration
Place jumpers/shunts as shown above for 4-wire resistive bridge configuration
This set of jumpers allows for changing the pin mapping of the AD7791 chip select line to different Arduino digital pins.
Place jumper/shunt as shown to connect to the corresponding Digital IO pin
CS - Arduino Digital Pin 10
CS - Arduino Digital Pin 9
CS - Arduino Digital Pin 8
If using an EVAL-CN0216-ARDZ board prior to Rev.C:
To change the CS pin, Install a 0-ohm resistor to resistor pads R7,R8 or R9
EVAL-CN0216-ARDZ Rev C Files
EVAL-CN0216-ARDZ Rev B Files
RevB to RevC: