DAC7750: Current not comming at Iout pin of IC even though

Image of connections on PCB: PCB_DAC7750

I have made minimum connections with DAC7750 namely AVDD(=11.5V), SDO, DIN, SCK, LATCH, GND as seen in the PCB (link to the image attached above).  I am just making the current ramp-up and ramp-down using ESP32 inbuilt SPI library. I am also facing the same issue, as current not being detected on the output (Measured with an ammeter). AVDD varied from 10V to 18V but still the same issue. DVDD is not connected as DVDD_EN is open, which means an internal supply is enabled for digital peripherals inside. I have verified through oscilloscope that MOSI, SCL, SS signals are being generated on ESP32's pins. I have used the HSPI ports of the controller. I have kept the delays a little high for easy debugging on an oscilloscope. 

#include <SPI.h>

//#define ALARM  
#define HSPI_MISO   12
#define HSPI_MOSI   13
#define HSPI_SCLK   14
#define HSPI_SS     15    //To be connected to LATCH pin of DAC7750

//see pg32 datasheet
#define Config   0x57
#define Ctrl     0x55
#define DAC_data 0x01
#define Reset    0x56

static const int spiClk = 1000; //freq in Hz

SPIClass SPI2(HSPI);

//Send values to DAC7750 in format 'address_of_register + data' 
//24-bit frame= 8bit addr + 16bit data
//See pg10, Datasheet for timing diagram
void Send(uint8_t addr, uint16_t value)
{ 
  SPI2.transfer(addr);
  SPI2.transfer16(value);    ///inbuilt function in SPI.h for 2bytes transfer
  digitalWrite(HSPI_SS, LOW);
  delay(1);
  digitalWrite(HSPI_SS, HIGH);
  delay(1);
}

void setup()
{ delay(1000);  //Let the power supply be stable. 

  pinMode(HSPI_SS, OUTPUT);
  digitalWrite(HSPI_SS, HIGH); 

//  pinMode(ALARM, INPUT);

  SPI2.begin(HSPI_SCLK, HSPI_MISO, HSPI_MOSI, HSPI_SS);

  SPI2.beginTransaction(SPISettings(spiClk, MSBFIRST, SPI_MODE0));
   
  //INITIALISE REGISTERS (pg34 onwards, Datasheet)
  //..Reset register
  Send(Reset, 0x0001); 
  delay(1);
  
  //..config register 
  Send(Config,0b0000000000001100);   //disable HART, watchdog, error-check, calliberation
  delay(1);
  
  //..Data register   -> initialise with all 0. (But is already at default reset)
  //Send(DAC_data, 0x0000);  //last 4 LSB digits invalid for DAC7750 (to act as 12-bit)
  //delay(1);
  
  //..Control register
  Send(Ctrl, 0b0011000000001110);  //o/p enable, o/p->0-20mA, current setting res enable
  delay(1);
}

void loop() 
{
  //send a ramp from 0 - 2mA, then const upto 30sec, then ramp to 0mA
  //ramp slope around 30sec
  uint16_t i=0;
  for(i=0; i<409; i++)  //Current upto 2mA i.e. 409.5 value of 12bit-DAC in 30sec
  {
    Send(DAC_data, (i<<4));
    delay(75);
  }

  delay(10000);

  for(i=409; i>=0; i--) //Current upto 2mA i.e. 409.5 value of 12bit-DAC in 30sec (16bit register, last 4bits useless)
  {
    Send(DAC_data, (i<<4));
    delay(75);
  }

  delay(10000);
  
}