AD5933 Impedance Converter Network analyzer module 1M sampling rate 12bit resolution measurement resistance

Product Application:

-Electrochemical analysis

-Bioelectrical impedance analysis

-Impedance spectrum analysis

-Complex impedance measurement

-Corrosion monitoring and protection equipment

-Biomedical and Automotive Sensors

-Bioelectrical impedance analysis

-Proximity sensing

-Non destructive testing

-Material Property Analysis

-Fuel/Cell Status Monitoring

#include "sys.h"

#include "ad5933.h"

#include "delay.h"

#include <math.h>

#define AD5933_ADDRESS     0x1A                  // Define AD5933 slave address, its default serial bus address is

                                                                          // 0001101(0x0D), but since the slave address high seven bits are the device address

                                    // (0x0D), the actual slave address is the device address shifted left by one bit

                                    // i.e. (0x1A)

#define    POINTER_COMMAND     0xB0          // Define pointer setting command (10110000)

#define Gain_factor 5.0725e-9

#define PI 3.1415926536

#define System_Phase 109.052767

#define rad_to_degree 180 / PI

double

GainFactor[] = {5.1143e-9, 5.1146e-9, 5.1162e-9, 5.11645e-9,

5.11699e-9, 5.1175e-9, 5.11774e-9, 5.1189e-9, 5.11983e-9, 5.12105e-9};

double SystemPhase[] = {290.994, 291.721, 292.452, 293.168, 293.870, 294.596, 295.336, 296.009, 296.750, 297.492};

int Receive_byte[1];                                   // Define receive array

short int status_register;                          // Define status register variable

int Re, Im;  // Real part, imaginary part

double Magnitude, Impedance, Phase;  // DFT amplitude value, impedance value, phase value

void AD5933_Init(void)

{

                  delay_ms(100);                                  // This delay is very important

                  // Transmit       to start frequency register

                  // program 30khz start frequency assuming internal osc of 16.776Khz

                  i2c_write ( 0x84, 0x45);

                  i2c_write ( 0x83, 0xA6);   

                  i2c_write ( 0x82, 0x0E);

                  // Transmit to frequency increment register

                  // program 1Khz frequency increment assuming internal osc of 16.776Khz

                  i2c_write ( 0x87, 0x02);

                  i2c_write ( 0x86, 0x7D);   

                  i2c_write ( 0x85, 0x00);

                  // Transmit to NUMBER OF INCREMENTS register

                  // program 10 frequency increments

                  i2c_write ( 0x89, 0x0A);

                  i2c_write ( 0x88, 0x00);

                  // Transmit to settling time cycles register

                  // program 15 output cycles at each frequency before a adc conversion

                  i2c_write ( 0x8B, 0x0F);

                  i2c_write ( 0x8A, 0x00);

                  // Transmit to CONTROL register

                  // place the AD5933 in standby mode

                  i2c_write ( 0x80, 0xB0);

                  // Choose the internal system clock

                  i2c_write ( 0x81, 0x00);

                  // initialise the sensor with contents of start frequency regsister with range 1 (2vp-p, 1.6v) PGA = x1

                  i2c_write ( 0x80, 0x11);

                  delay_ms(5);  // This delay is to allow the circuit to reach a stable state after sending the initialization command

                  // start of frequency sweep  (2vp-p, 1.6v) PGA = x1

                  i2c_write ( 0x80, 0x21);

                  // initialise the sweep sequence

}

void sweep (void)

{

   unsigned int real_byte_high;

   unsigned int real_byte_low;

   unsigned int imag_byte_high;

   unsigned int imag_byte_low;

   signed short int imag_data;

   signed short int real_data;

   int m = 0;  // Gain factor array and system phase array counter

   printf ("Start of Frequency sweep");       // printf function call  

   delay_ms(10);

   for(;;)

      // status reg D0 = valid temp, D1 = valid real/imag data, D2 = frequency sweep complete

      {

      // D1 status reg loop

      status_register = AD5933_read(0x8F);     // read the status register

      status_register = (status_register & 0x2);   // mask off the valid data bit

      if( ((status_register) 0xFD ) == 0xFF)      // valid data should be present after start freqy command

         {

         //D1 true condition

         if( (AD5933_read(0x8F) 0xFB )!=  0xFF)       // D2 test condition

            {

            real_byte_high = AD5933_read(0x94);

            real_byte_low =  AD5933_read(0x95);

            imag_byte_high = AD5933_read(0x96);

            imag_byte_low =  AD5933_read(0x97);

            real_data = ((real_byte_high << 8)   real_byte_low);                         

            imag_data = ((imag_byte_high << 8)   imag_byte_low);

                          Re = (int) real_data;

                          Im = (int) imag_data;

                          Magnitude = sqrt(pow(Re,2) + pow(Im,2));

                          Impedance = 1/(Magnitude * GainFactor[m]);

                          if(Re>0 && Im>0)

                          Phase = (atan((double)Im / (double)Re) * rad_to_degree) - SystemPhase[m];

                          else if(Re>0 && Im<0)

                          Phase = (360+ atan((double)Im / (double)Re) * rad_to_degree) - SystemPhase[m];

                          else

                          Phase = (180+ atan((double)Im / (double)Re) * rad_to_degree) - SystemPhase[m];

                          printf ("The Impedance is %f ohm", Impedance);

                          delay_ms(10);

                          printf ("The Phase is %f degree", Phase);

                          delay_ms(10);

            m++;

            i2c_write ( 0x80, 0x31);                    // increment to the next frequency

            } // end of D2 test condition

         else // End of frequency sweep exit loop

            {

            break;

            }

         } // end of D1 true condition

      } // end of for loop

}// end of sweep function