I am using DC energy meter as slave.When I am testing DC energy meter using Modbus tester tool,its showing value from 1 to 24 register.I am using my own atmega328P with on board RS485 as a master device.I have connected A,B from slave to mater board.Now,I want to read slave outputs using my master.For that I have written below mentioned code.when I am serially printing array,its showing 00000000000000000000000000000000769.I am not getting full data on my master.
#include <ModbusRtu.h>
// data array for modbus network sharing
uint16_t au16data[64];
uint8_t u8state;
int i;
/**
* Modbus object declaration
* u8id : node id = 0 for master, = 1..247 for slave
* u8serno : serial port (use 0 for Serial)
* u8txenpin : 0 for RS-232 and USB-FTDI
* or any pin number > 1 for RS-485
*/
Modbus master(0,0,1); // this is master and RS-232 or USB-FTDI
/**
* This is an structe which contains a query to an slave device
*/
modbus_t telegram;
unsigned long u32wait;
void setup() {
master.begin( 9600 ); // baud-rate at 19200
master.setTimeOut( 2000 ); // if there is no answer in 2000 ms, roll over
u32wait = millis() + 1000;
u8state = 0;
}
void loop() {
switch( u8state ) {
case 0:
if (millis() > u32wait) u8state++; // wait state
break;
case 1:
telegram.u8id = 1; // slave address
telegram.u8fct = 3; // function code (this one is registers read)
telegram.u16RegAdd = 1; // start address in slave
telegram.u16CoilsNo = 24; // number of elements (coils or registers) to read
telegram.au16reg = au16data; // pointer to a memory array in the Arduino
master.query( telegram ); // send query (only once)
u8state++;
break;
case 2:
master.poll(); // check incoming messages
if (master.getState() == COM_IDLE) {
u8state = 0;
u32wait = millis() + 100;
}
break;
}
//au16data[4] = analogRead( 0 );
for(i=0;i<=64;i++)
{
Serial.print(au16data[i]);
}
Serial.println("\n");
Serial.println("\n");
delay(1000);
}