ADS1198: Can't read channel input with Arduino UNO

Hello,

I'm trying capture signal with channel 1 ADS1198 and send it via SPI to Arduino UNO in my school project. Due to quarantine I don't have electrodes, so I'm trying to use potentiometer to simulate source of data. I'm unable to see any difference in captured data, while I'm moving with potentiometer.

My wiring is:

ADS1198 -> Arduino UNO

DIN -> pin 11

CS ->  pin A5

DOUT-> pin 12

DRDY-> pin 2

SCLK-> pin 13

AVDD-> 5V

DGND-> 3,3V

IN1P-> potentiometer

IN1N-> GND

My code is written in Arduino IDE:

#include <SPI.h>

#define MOSI1    11 //MOSI
#define MISO1    12 //MISO
#define CLK1     13 //SCK

#define PIN_CS     A5
#define PIN_RESET  A4
#define PIN_DRDY   2

#define RREG       0x20
#define WREG       0x40

#define ID         0x00
#define SDATAC     0x11
#define RDATAC     0x10
#define RDATA      0x12

#define WAKEUP     0x02
#define STANDBY    0x04
#define RESET      0x06
#define START      0x08
#define STOP       0x0A

#define CH1        0x05
#define CH2        0x06
#define CH3        0x07
#define CH4        0x08
#define CH5        0x09
#define CH6        0x0A
#define CH7        0x0B
#define CH8        0x0C

#define SETOFF     B10000001
#define SETPGA6    B00000000
#define SETPGA1    B00010000
#define SETPGA12   B01100000 

#define SPI_SPEED  2500000
#define NOP        0x00

uint16_t chSet;
double real_val;
const int datasize = 400; 
volatile int data[datasize];
volatile int DRDY_state = HIGH;
void waitforDRDY();
void DRDY_Interrupt();
void prepare_ADS();
void packet_init();
int16_t read_Value();
void send_command(uint8_t cmd);
uint8_t out1, out2, out3;
uint8_t debug_msg = 1U;
String sep = "---------------------------------------------------------";
String hex_to_char(int hex_in) {
  int precision = 2;
  char tmp[16];
  char format[128];
  sprintf(format, "0x%%.%dX", precision);
  sprintf(tmp, format, hex_in);
  //Serial.print(tmp);
  return(String(tmp));
}

void DRDY_Interrupt(){
  DRDY_state = LOW;  
}

void waitforDRDY(){
  while(DRDY_state){
    continue;  
  }
  noInterrupts();
  DRDY_state = HIGH;
  interrupts();
}

int16_t read_Value(){
  int16_t adc_val = 0;
  waitforDRDY();
  SPI.beginTransaction(SPISettings(SPI_CLOCK_DIV8, MSBFIRST, SPI_MODE1));
  digitalWrite(PIN_CS, LOW);
  delayMicroseconds(5);
  SPI.transfer(RDATA);
  delayMicroseconds(7);
  adc_val |= SPI.transfer(NOP);
  Serial.println(adc_val);
  delayMicroseconds(10);
  adc_val <<= 8;
  adc_val |= SPI.transfer(NOP);
  Serial.println(adc_val);
  delayMicroseconds(10);
  digitalWrite(PIN_CS, HIGH);
  SPI.endTransaction();

  return adc_val;
}

uint8_t read_byte(uint8_t reg_addr)
{
    int out = 0;
    
    digitalWrite(PIN_CS, LOW);

    send_command(RDATA);
    out1 = SPI.transfer(0x00);
    Serial.println(out1);
    delayMicroseconds(5);
    out2 = SPI.transfer(0x00);
    Serial.println(out2);
    delayMicroseconds(5);
    out3 = SPI.transfer(0x00);
    Serial.println(out3);
    delayMicroseconds(1);
    digitalWrite(PIN_CS, HIGH);
    out = (out1 << 8) + out2;
    /*if(debug_msg)
    {
        Serial.println(sep);
        Serial.println( "sent:\t" + hex_to_char(reg_addr) );
        Serial.println( "recieved:\t" + out);
    }
    */
    return(out);
}

void prepare_ADS(){
  digitalWrite(PIN_CS, LOW);
  delay(2);
  SPI.setDataMode(SPI_MODE1);
  SPI.setBitOrder(MSBFIRST);
  SPI.setClockDivider(SPI_CLOCK_DIV8);
  SPI.begin();
}

void ADS_init_config(){
  attachInterrupt(digitalPinToInterrupt(PIN_DRDY), DRDY_Interrupt, FALLING);
  digitalWrite(PIN_CS, LOW);
  SPI.transfer(WAKEUP);
  SPI.transfer(SDATAC);
  delay(2);

  SPI.transfer(WREG | 0x01);
  SPI.transfer(0x02);

  //Config1
  SPI.transfer(B10000110);

  //Config2
  SPI.transfer(0x00);

  //Config3
  SPI.transfer(B11101001);

  SPI.transfer(WREG | 0x05);
  SPI.transfer(0x07);
  //CH1
  SPI.transfer(B00000001);
  //CH2
  SPI.transfer(B00000001);
  //CH3
  SPI.transfer(B00000001);
  //CH4
  SPI.transfer(B00000001);
  //CH5
  SPI.transfer(B00000001);
  //CH6
  SPI.transfer(B00000001);
  //CH7
  SPI.transfer(B00000001);
  //CH8
  SPI.transfer(B00000001);

  digitalWrite(PIN_CS, HIGH);
}


void send_command(uint8_t cmd)
{
    digitalWrite(PIN_CS, LOW);
    delayMicroseconds(5); // 5 = 6us at 32
    SPI.transfer(cmd);
    delayMicroseconds(10);
    digitalWrite(PIN_CS, HIGH);
}

void set_channel(uint8_t ch, uint8_t settings){
    SPI.transfer(WREG | ch);
    SPI.transfer(0x00);
    SPI.transfer(settings);  
}

void packet_init(){
  for(int i = 0; i < datasize; ++i){
    data[i] = 0;  
  }
}

void setup() 
{
    Serial.begin(9600);
    pinMode(CLK1,OUTPUT);
    pinMode(MISO1,INPUT); 
    pinMode(MOSI1,OUTPUT);
    pinMode(PIN_CS,OUTPUT);
    pinMode(PIN_RESET,OUTPUT);
    //pinMode(PIN_START,OUTPUT);
    pinMode(PIN_DRDY,INPUT);
    digitalWrite(PIN_CS,HIGH);
    //digitalWrite(PIN_START,LOW);
    
    prepare_ADS();
    ADS_init_config();
    delay(1000);
    digitalWrite(PIN_CS, LOW);
    delay(1000);
    digitalWrite(PIN_CS, HIGH);
    delay(1000);    
    send_command(SDATAC);
    delay(10);
    set_channel(CH1, SETPGA1);
}

void loop()
{
    //chSet = read_byte(RREG | ID);
    //Serial.print("-- ID" + String(chSet) + "--");
    //real_val = (double)5*(double)read_Value()/(double)65535;
    read_Value();
    Serial.println(real_val);
    delay(1000);
}

I would be pleased for any advice.

Best regards,

Michael