Modbus86 Master

[Modbus]

The Modbus86 Master enables the 86Duino to emulate a Modbus Master and send packets to the Slave node on the channel.

Example

Example of Modbus Master with RS485 enabled and using Modbus RTU as the communication method.

#include <Modbus86.h>
 
ModbusMaster bus;
ModbusMasterNode node1;
ModbusMasterNode node2;
 
int led = 0;
uint32_t value = 0;
 
void setup()
{
    Serial485.begin(115200);
     
    /* Modbus RTU Mode via RS485. */
    bus.begin(MODBUS_RTU, Serial485);
     
    /* Slave node 1 with ID 11. */
    node1.attach(11, bus);
    /* Slave node 2 with ID 12. */
    node2.attach(12, bus);
}
 
void loop()
{
    uint16_t reg[2];
     
    /* Write 1 coil to address 0 of the slave with ID 11. */
    node1.writeSingleCoil(0, led);
     
    /* Write 2 word to holding registers address 16 of
       the slave with ID 11. */
    reg[0] = value & 0xFFFF;
    reg[1] = (value >> 16) & 0xFFFF;
    node1.setTransmitBuffer(0, reg[0]);
    node1.setTransmitBuffer(1, reg[1]);
    node1.writeMultipleRegisters(16, 2);
 
    /* Read 2 word from holding registers address 16 of
       the slave with ID 11. */
    node1.readHoldingRegisters(16, 2);
    Serial.print("From Node 1 Holding Register: ");
    value = node1.getResponseBuffer(0)
        | (node1.getResponseBuffer(1) << 16);
    Serial.println(value);
 
    /* Read 1 word from input registers address 2 of
       the slave with ID 11. */
    node1.readInputRegisters(2, 1);
    Serial.print("              Input Register: ");
    Serial.print(node1.getResponseBuffer(0));
    Serial.println();
     
    /* Write 1 coil to address 0 of the slave with ID 12. */
    node2.writeSingleCoil(0, led);
     
    /* Write 2 word to holding registers address 16 of
       the slave with ID 12. */
    reg[0] = value & 0xFFFF;
    reg[1] = (value >> 16) & 0xFFFF;
    node2.setTransmitBuffer(0, reg[0]);
    node2.setTransmitBuffer(1, reg[1]);
    node2.writeMultipleRegisters(16, 2);
 
    /* Read 2 word from holding registers address 16
       of the slave with ID 12. */
    node2.readHoldingRegisters(16, 2);
    Serial.print("From Node 2 Holding Register: ");
    value = node2.getResponseBuffer(0)
        | (node2.getResponseBuffer(1) << 16);
    Serial.println(value);
 
    /* Read 1 word from input registers address 2 of
       the slave with ID 12. */
    node2.readInputRegisters(2, 1);
    Serial.print("              Input Register: ");
    Serial.print(node2.getResponseBuffer(0));
    Serial.println();
     
    led = !led;
    value++;
     
    delay(1000);
}

Example of a Modbus Master using Ethernet and Modbus TCP as the communication method.

#include <Ethernet.h>
#include <Modbus86.h>
 
ModbusMaster bus;
ModbusMasterNode node;
 
byte mac[] = {0x00, 0x00, 0x00, 0x00, 0x00, 0x00};
IPAddress localIp(192,168,1,101);
IPAddress serverIp(192,168,1,102);
 
int led = 0;
uint32_t value = 0;
 
void setup()
{
    Ethernet.begin(mac, localIp);
     
    /* Modbus TCP Mode via Ethernet. */
    bus.begin(MODBUS_TCP, serverIp);
     
    /* Slave node initialize. */
    node.attach(11, bus);
}
 
void loop()
{
    uint16_t reg[2];
     
    /* Write 1 coil to address 0 of the slave with ID 11. */
    node.writeSingleCoil(0, led);
     
    /* Write 2 word to holding registers address 16 of
       the slave with ID 11. */
    reg[0] = value & 0xFFFF;
    reg[1] = (value >> 16) & 0xFFFF;
    node.setTransmitBuffer(0, reg[0]);
    node.setTransmitBuffer(1, reg[1]);
    node.writeMultipleRegisters(16, 2);
 
    /* Read 2 word from holding registers address 16 of
       the slave with ID 11. */
    node.readHoldingRegisters(16, 2);
    Serial.print("From Node 1 Holding Register: ");
    value = node.getResponseBuffer(0)
        | (node.getResponseBuffer(1) << 16);
    Serial.println(value);
 
    /* Read 1 word from input registers address 2 of
       the slave with ID 11. */
    node.readInputRegisters(2, 1);
    Serial.print("              Input Register: ");
    Serial.print(node.getResponseBuffer(0));
    Serial.println();
     
    led = !led;
    value++;
     
    delay(1000);
}

Libraries Reference Home

The text of the 86Duino reference is a modification of the Arduino reference and is licensed under a Creative Commons Attribution-ShareAlike 3.0 License. Code samples in the reference are released into the public domain.

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