PsuedoDifferential measurements on PmodAD5

[Yacov Cohen]

Trying to use PsuedoDifferential measurements. See software bellow posted by Anne. By obvious there are some mistakes on original script. 

There are some bugs I tried to repair, here is the modified software  set ground on pin 9 placed +1 volt to pin1 AIN1 ground of voltage source AINCOM (pin9) but could not get results.

Please Help 

 

 

the program

/*

AD7193_VoltageMeasurePsuedoDifferential_Example

Configures and calibrates the AD7193 to measure psuedo-differential voltage on channel 6

Tutorial can be found at <TBD>, and uses the PmodAD5 from Digilent.

Signal Connections:
-----------------------------------------------------
 Signal Name |  PmodAD Pin  |  Arduino Pin
-----------------------------------------------------
  ~CS        |  J1, Pin 1   |  10
  MOSI       |  J1, Pin 2   |  MOSI or 11 or ICSP-4
  MISO       |  J1, Pin 3   |  MISO or 12 or ICSP-1
  SCLK       |  J1, Pin 4   |  SCLK or 13 or ICSP-3
  GND        |  J1, Pin 5   |  GND
  VCC (3.3V) |  J1, Pin 6   |  3.3V
-----------------------------------------------------

-----------------------------------
 Signal Name       |  PmodAD5 Pin   
-----------------------------------
 Channel 6 Pos     |  J2, Pin 7
 AINCOM            |  J2, Pin 9
-----------------------------------
See Table 24 of AD7193 datasheet for more information

Refer to:
https://reference.digilentinc.com/reference/pmod/pmodad5/start
https://www.arduino.cc/en/Reference/SPI

Created 4 Oct 2016
by Anne Mahaffey

This example code is in the public domain
*/

 

 

 

#include <SPI.h>
#include <AD7193.h>

AD7193 AD7193;

void setup() {
 
  ///////////////////////////
  // setup Serial and SPI
  ///////////////////////////
 
  Serial.begin(9600);
  delay(1000);
 
  while (!Serial) {
    ; // wait for serial port to connect. Needed for native USB port only
  }
 
  AD7193.begin();

  ///////////////////////////////////
  // Device setup
  ///////////////////////////////////
 
  AD7193.AppendStatusValuetoData();  //This might be a requirement - functions will be simpler if I can assume this is true 
 
  AD7193.SetPGAGain(1);

  AD7193.SetAveraging(100);

  // sets input to measure across channel input and AINCOM pin
  AD7193.SetPsuedoDifferentialInputs();

  /////////////////////////////////////
  // Calibrate with given PGA settings - need to recalibrate if PGA setting is changed
  /////////////////////////////////////
 
  AD7193.Calibrate();

  // Debug - Check register map values
  AD7193.ReadRegisterMap();
 

  //////////////////////////////////////
 
  Serial.println("\nBegin AD7193 conversion - single conversion (pg 35 of datasheet, figure 25)");
}

void loop() {

  unsigned long ch1Data;
  float ch1Voltage;
 
  // Read channel measurement data
  ch1Data = (AD7193.ReadADCChannel(1) >> 8);

  //Serial.print("  CH1 data: ");
  //Serial.print(ch1Data, HEX);

  // Convert to voltage
  ch1Voltage = AD7193.DataToVoltage(ch1Data);
 
  Serial.print("\n\t\tChanne1 1 Voltage Measurement: ");
  Serial.println(ch1Voltage, 3); 
  
  delay(100);
}