Enum modbus_rtu::packet::Request

pub enum Request {
    ReadCoils {
        slave: u8,
        base_address: u16,
        quantity: u16,
    },
    ReadDiscreteInputs {
        slave: u8,
        base_address: u16,
        quantity: u16,
    },
    ReadHoldingRegisters {
        slave: u8,
        base_address: u16,
        quantity: u16,
    },
    ReadInputRegisters {
        slave: u8,
        base_address: u16,
        quantity: u16,
    },
    WriteSingleCoil {
        slave: u8,
        address: u16,
        data: bool,
    },
    WriteSingleRegister {
        slave: u8,
        address: u16,
        data: u16,
    },
    WriteMultipleCoils {
        slave: u8,
        base_address: u16,
        data: Vec<bool>,
    },
    WriteMultipleRegisters {
        slave: u8,
        base_address: u16,
        data: Vec<u16>,
    },
    MaskWriteRegister {
        slave: u8,
        address: u16,
        and_mask: u16,
        or_mask: u16,
    },
    ReadWriteMultipleRegisters {
        slave: u8,
        read_base_address: u16,
        read_quantity: u16,
        write_base_address: u16,
        data: Vec<u16>,
    },
}

Request

Modbus RTU request packet variants.

Variants

ReadCoils

ReadCoils (0x01)

Request to read multiple coils. A coil is a single-bit memory that the master can read and write.

• slave: Address of the target device. It must not be zero.
• base_address: Base coil address to start reading. base_address + quantity - 1 must not exceed 0xFFFF.
• quantity: Number of coils to read. It must be less than or equal to 255 due to the response byte counter being 8-bit.

Fields

slave: u8

base_address: u16

quantity: u16

ReadDiscreteInputs

ReadDiscreteInputs (0x02)

Request to read multiple discrete inputs. A discrete input is a single-bit memory that the master can only read.

• slave: Address of the target device. It must not be zero.
• base_address: Base discrete input address to start reading. base_address + quantity - 1 must not exceed 0xFFFF.
• quantity: Number of discrete inputs to read. It must be less than or equal to 255 due to the response byte counter being 8-bit.

Fields

slave: u8

base_address: u16

quantity: u16

ReadHoldingRegisters

ReadHoldingRegisters (0x03)

Request to read multiple holding registers. A holding register is a 16-bit memory that the master can read and write.

• slave: Address of the target device. It must not be zero.
• base_address: Base holding register address to start reading. base_address + quantity - 1 must not exceed 0xFFFF.
• quantity: Number of holding registers to read. It must be less than or equal to 125 due to the maximum packet size of 256.

Fields

slave: u8

base_address: u16

quantity: u16

ReadInputRegisters

ReadInputRegisters (0x04)

Request to read multiple input registers. An input register is a 16-bit memory that the master can only read.

• slave: Address of the target device. It must not be zero.
• base_address: Base input register address to start reading. base_address + quantity - 1 must not exceed 0xFFFF.
• quantity: Number of input registers to read. It must be less than or equal to 125 due to the maximum packet size of 256.

Fields

slave: u8

base_address: u16

quantity: u16

WriteSingleCoil

WriteSingleCoil (0x05)

Request to write a single coil. A coil is a single-bit memory that the master can read and write.

• slave: Address of the target device.
• address: Coil address to write to.
• data: Data to write. true represents ON, and false represents OFF.

Fields

slave: u8

address: u16

data: bool

WriteSingleRegister

WriteSingleRegister (0x06)

Request to write a single holding register. A holding register is a 16-bit memory that the master can read and write.

• slave: Address of the target device.
• address: Holding register address to write to.
• data: Data to write.

Fields

slave: u8

address: u16

data: u16

WriteMultipleCoils

WriteMultipleCoils (0x0F)

Request to write multiple coils. Coils are single-bit memory that the master can read and write.

• slave: Address of the target device to write to.
• base_address: Base coil address to start writing. base_address + length_of_data - 1 must not exceed 0xFFFF.
• data: Data to write. The length of the data must be less than or equal to 1976 due to the maximum packet size of 256.

Fields

slave: u8

base_address: u16

data: Vec<bool>

WriteMultipleRegisters

WriteMultipleRegisters (0x10)

Request to write multiple holding registers. Holding registers are 16-bit memory that the master can read and write.

• slave: Address of the target device.
• base_address: Base holding register address to start writing. base_address + length_of_data - 1 must not exceed 0xFFFF.
• data: Data to write. The length of the data must be less than or equal to 123 due to the maximum packet size of 256.

Fields

slave: u8

base_address: u16

data: Vec<u16>

MaskWriteRegister

MaskWriteRegister (0x16)

Request to apply AND and OR masks to a single holding register. A holding register is a 16-bit memory that the master can read and write.

• slave: Address of the target device.
• address: Holding register address to apply masks to.
• and_mask: AND mask to apply.
• or_mask: OR mask to apply.

Fields

slave: u8

address: u16

and_mask: u16

or_mask: u16

ReadWriteMultipleRegisters

ReadWriteMultipleRegisters (0x17)

Request to write to multiple holding registers and read from multiple holding registers. Holding registers are 16-bit memory that the master can read and write.

• slave: Address of the target device. It must not be zero.
• read_base_address: Base holding register address to start reading. read_base_address + read_quantity - 1 must not exceed 0xFFFF.
• read_quantity: Number of holding registers to read. It must be less than or equal to 125 due to the maximum packet size of 256.
• write_base_address: Base holding register address to start writing. write_base_address + length_of_data - 1 must not exceed 0xFFFF.
• data: Data to write. The length of the data must be less than or equal to 121 due to the maximum packet size of 256.

Fields

slave: u8

read_base_address: u16

read_quantity: u16

write_base_address: u16

data: Vec<u16>

Implementations

impl Request

pub fn function_code(&self) -> u8

function_code

Returns the function code that corresponds to the request.

pub fn expect_len(&self) -> usize

expect_len

Return expect response packet size. Note that this size is in case of the slave return successfully. If slave returns expection code, you should expect for 5 bytes.

pub fn to_bytes(&self) -> Result<Vec<u8>, RequestError>

to_byte

Generate actual packet to send

Trait Implementations

impl Clone for Request

fn clone(&self) -> Request

Returns a copy of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for Request

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.