- arduino uno
- shield rs485
- material kecil (led, resistor dll)
1. usb to rs485
langkah-langkah:
1. run arduino IDE (1.6.4)
2. tancepin arduino dan shield rs485 (posisikan off dipswitchnya saat upload)
3. upload sketch dibawah ini:
#include <ModbusRtu.h>
#define ID 1
#define TXEN 2
Modbus slave(ID, 0, TXEN); // this is slave ID and RS-232 or USB-FTDI
boolean led;
int8_t state = 0;
unsigned long tempus;
// data array for modbus network sharing
uint16_t au16data[9];
/**
* Setup procedure
*/
void setup() {
io_setup(); // I/O settings
// start communication
slave.begin( 19200 );
tempus = millis() + 100;
digitalWrite(13, HIGH );
}
/**
* Loop procedure
*/
void loop() {
// poll messages
// blink led pin on each valid message
state = slave.poll( au16data, 9 );
if (state > 4) {
tempus = millis() + 50;
digitalWrite(13, HIGH);
}
if (millis() > tempus) digitalWrite(13, LOW );
// link the Arduino pins to the Modbus array
io_poll();
}
/**
* pin maping:
* 3 - digital input
* 4 - digital input
* 5 - digital input
* 6 - digital output
* 7 - digital output
* 8 - digital output
* 9 - digital output
* 10 - analog output
* 11 - analog output
* 14 - analog input
* 15 - analog input
*
* pin 13 is reserved to show a successful query
*/
void io_setup() {
// define i/o
pinMode(3, INPUT);
pinMode(4, INPUT);
pinMode(5, INPUT);
pinMode(6, OUTPUT);
pinMode(7, OUTPUT);
pinMode(8, OUTPUT);
pinMode(9, OUTPUT);
pinMode(10, OUTPUT);
pinMode(11, OUTPUT);
pinMode(13, OUTPUT);
digitalWrite(6, LOW );
digitalWrite(7, LOW );
digitalWrite(8, LOW );
digitalWrite(9, LOW );
digitalWrite(13, HIGH ); // this is for the UNO led pin
analogWrite(10, 0 );
analogWrite(11, 0 );
}
/**
* Link between the Arduino pins and the Modbus array
*/
void io_poll() {
// get digital inputs -> au16data[0]
bitWrite( au16data[0], 1, digitalRead( 3 ));
bitWrite( au16data[0], 2, digitalRead( 4 ));
bitWrite( au16data[0], 3, digitalRead( 5 ));
// set digital outputs -> au16data[1]
digitalWrite( 6, bitRead( au16data[1], 0 ));
digitalWrite( 7, bitRead( au16data[1], 1 ));
digitalWrite( 8, bitRead( au16data[1], 2 ));
digitalWrite( 9, bitRead( au16data[1], 3 ));
// set analog outputs
analogWrite( 10, au16data[2] );
analogWrite( 11, au16data[3] );
// read analog inputs
au16data[4] = analogRead( 0 );
au16data[5] = analogRead( 1 );
// diagnose communication
au16data[6] = slave.getInCnt();
au16data[7] = slave.getOutCnt();
au16data[8] = slave.getErrCnt();
}
4. setelah upload, posisikan on dipswitchnya
5. pasang kabel data A dan data B pada usb to rs485 dan shield rs485
6. Test menggunakan modscan (sesuaikan com port usb to rs485, parity, ID, baudrate)
