readCoil()

Posted by On 01 / 31 / 2019 0 Comment

Description

Read the Coils register.

Syntax

node1.readCoil(address) node2.readCoil(address, size, buffer)

Parameters

node1/node2: ModbusSlaveNode object.

address: Coils register address to be read.

size: The number of Coils registers to be read.

buffer: Copy the read Coils register array data to the array space pointed to by buffer.

Return

int: Return the Coil position data when using only the address parameter, which is MODBUS_COIL_ON or MODBUS_COIL_OFF. When reading using the specified buffer, it returns MODBUS_SUCCESS, otherwise it returns EXCEPTION_CODE.

Example

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#include <Modbus86.h>

 

ModbusSlave bus;

ModbusSlaveNode node;

 

uint8_t write_single_coil(  uint8_t function,

                             uint16_t address,

                             uint16_t length)

{

    uint16_t value;

     

    if (address == 0) {

        node.readCoil(address, 1, &value);

        if (value)

            digitalWrite(LED_BUILTIN, HIGH);

        else

            digitalWrite(LED_BUILTIN, LOW);

    }

 

    return MODBUS_SUCCESS;

}

 

void setup()

{

    pinMode(LED_BUILTIN, OUTPUT);

     

    Serial485.begin(115200);

     

    /* Modbus RTU Mode via RS485. */

    bus.begin(MODBUS_RTU, Serial485);

     

    /* Slave node with ID 11. */

    node.attach(11, bus);

 

    /* Set the callback function of Write Single Coil (0x05). */

    node.cbFunc[MODBUS_CB_WRITE_SINGLE_COIL]

              &n bsp;             = write_single_coil;

     

}

 

void loop()

{   

    node.poll();

}

See Also

– writeCoil()

Library Reference

The text in the 86Duino reference is modified from the Arduino reference and is licensed under the Creative Commons Attribution-Share Alike 3.0 License  . The code examples in the reference have been released into the public domain.