Arduino Modbus Master in_5 minutes

Arduino_Modbus_Master complete test

Master_modbus_RTU.ino

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+/**
+ *  Modbus master example 2:
+ *  The purpose of this example is to query several sets of data
+ *  from an external Modbus slave device. 
+ *  The link media can be USB or RS232.
+ *
+ *  Recommended Modbus slave: 
+ *  diagslave http://www.modbusdriver.com/diagslave.html
+ *
+ *  In a Linux box, run 
+ *  "./diagslave /dev/ttyUSB0 -b 19200 -d 8 -s 1 -p none -m rtu -a 1"
+ *  This is:
+ *   serial port /dev/ttyUSB0 at 19200 baud 8N1
+ *  RTU mode and address @1
+ *
+  */
+
+//// http://pdacontrol.blogspot.com.co/2016/03/pruebas-libreria-modbus-rtu-maestro-con.html
+
+
+
+#include <ModbusRtu.h>
+
+
+/// oled debuging
+
+#include <SPI.h>
+#include <Wire.h>
+#include <Adafruit_GFX.h>
+#include <Adafruit_SSD1306.h>
+
+#define OLED_RESET 4 // not used / nicht genutzt bei diesem Display
+Adafruit_SSD1306 display(OLED_RESET);
+
+
+///  
+
+uint16_t au16data[32]; //!< data array for modbus network sharing  Array
+uint8_t u8state; //!< machine state
+uint8_t u8query; //!< pointer to message query
+
+/**
+ *  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(0,0,7); // this is master and RS-232 or USB-FTDI  ///  7 = PIN ENEABLE rs485
+
+/**
+ * This is an structe which contains a query to an slave device
+ */
+modbus_t telegram[2];
+
+unsigned long u32wait;
+
+
+
+void setup() {
+
+  // initialize with the I2C addr 0x3C / mit I2C-Adresse 0x3c initialisieren
+  display.begin(SSD1306_SWITCHCAPVCC, 0x3C);
+  display.display();
+  delay(2000);
+  display.clearDisplay();
+  display.setTextSize(0.5);
+  display.setTextColor(INVERSE); 
+
+  //////////////////////////////
+
+  // telegram 0: read registers
+  telegram[0].u8id = 1;                 // slave address
+  telegram[0].u8fct = 3;                // function code (registers read multiple  3) 
+  telegram[0].u16RegAdd = 0;            // start address in slave -  direccion de Inicio 0
+  telegram[0].u16CoilsNo = 10;          // number of elements (coils or registers) to read  0 - 16 
+  telegram[0].au16reg = au16data;       // pointer to a memory array in the Arduino - Almacenamiento en Array de memoria de arduino
+
+  // telegram 1: write a multiple  register = function 16
+  telegram[1].u8id = 1;                 // slave address
+  telegram[1].u8fct = 16;               // function code (write multiple registers 16 )
+  telegram[1].u16RegAdd = 10;           // start address in slave  -  direccion de Inicio 10
+  telegram[1].u16CoilsNo = 10;          // number of elements (coils or registers) to read
+  telegram[1].au16reg = au16data+10;    // pointer to a memory array in the Arduino - Almacenamiento en Array de memoria de arduino 10 posiciones despues
+
+
+  master.begin( 19200 ); // baud-rate at 19200
+  master.setTimeOut( 5000 ); // if there is no answer in 5000 ms, roll over
+  u32wait = millis() + 1000;
+  u8state = u8query = 0;   
+}
+
+void loop() {
+  switch( u8state ) {
+  case 0: 
+    if (millis() > u32wait) u8state++; // wait state
+    break;
+  case 1: 
+    master.query( telegram[u8query] ); // send query (only once)
+    u8state++;
+ u8query++;
+ if (u8query > 2) u8query = 0;
+    break;
+  case 2:
+    master.poll(); // check incoming messages
+    if (master.getState() == COM_IDLE) {
+      u8state = 0;
+      u32wait = millis() + 1000; 
+    }
+    break;
+  }
+
+   display.clearDisplay();
+
+  //Read Multiple Holding Register  - Lectura de multiples registros 
+
+   display.setCursor(0,0); 
+   display.print(au16data[0]);    // Read Holding Register [0]
+   display.print(",");    
+   display.print(au16data[1]);    // Read Holding Register [1]
+   display.print(",");    
+   display.print(au16data[2]);    // Read Holding Register [2]
+   display.print(","); 
+   display.print(au16data[3]);    // Read Holding Register [3]
+   display.print(",");     
+   display.print(au16data[4]);    // Read Holding Register [4]
+   display.print(" Hold 0-4");
+
+   display.setCursor(0,8);  
+   display.print(au16data[5]);   // Read Holding Register [5]
+   display.print(",");     
+   display.print(au16data[6]);   // Read Holding Register [6]
+   display.print(",");   
+   display.print(au16data[7]);   // Read Holding Register [7]
+   display.print(",");   
+   display.print(au16data[8]);   // Read Holding Register [8]
+   display.print(",");    
+   display.print(au16data[9]);   // Read Holding Register [9]
+   display.print(" Hold 5-9");
+
+
+
+
+  //Write Multiple Holding Register  - Escritura de multiples registros 
+
+   au16data[10] = analogRead( 0 ); // Write Holding Register [10]
+
+   au16data[11] = analogRead( 0 ); // Write Holding Register [11]
+
+   au16data[12] = analogRead( 0 ); // Write Holding Register [12]
+
+   au16data[13] = analogRead( 0 ); // Write Holding Register [13]
+
+   au16data[14] = analogRead( 0 ); // Write Holding Register [14]
+
+   au16data[15] = analogRead( 0 ); // Write Holding Register [15]
+
+   au16data[16] = analogRead( 0 ); // Write Holding Register [16]
+
+   au16data[17] = analogRead( 0 ); // Write Holding Register [17]
+
+   au16data[18] = analogRead( 0 ); // Write Holding Register [18]
+
+   au16data[19] = analogRead( 0 ); // Write Holding Register [19]
+
+
+// Print Oled Write Holding Register 
+
+   display.setCursor(0,16); 
+   display.print(au16data[10]);    
+   display.print(",");    
+   display.print(au16data[11]);
+   display.print(",");    
+   display.print(au16data[12]);    
+   display.print(","); 
+   display.print(au16data[13]);    
+   display.print(",");     
+   display.print(au16data[14]);
+   display.print(",");    
+   display.print(au16data[15]);    
+   display.print(",");    
+   display.print(au16data[16]);
+   display.print(",");    
+   display.print(au16data[17]);    
+   display.print(","); 
+   display.print(au16data[18]);    
+   display.print(",");     
+   display.print(au16data[19]);
+   display.print(" Hold 10-19");
+
+
+   display.display();  
+
+
+
+
+
+} 
+