Struct Response 

pub struct Response<'a> { /* private fields */ }

A borrowed view over a response PDU, for reading the values a device returned.

A read response is a function code, a byte count, and then the data. registers and coils decode that data into the 16-bit words or the packed bits it represents; exception recognizes the alternative, a device that refused the request. The view borrows the PDU and copies nothing.

Examples

use pamoja_modbus::{Pdu, Response};

// A soil probe's reply to a read of three registers: nitrogen, phosphorus, and
// potassium, in milligrams per kilogram.
let reply = Pdu::read_holding_registers_reply(&[555, 0, 100]).unwrap();
let values: Vec<u16> = Response::new(reply.as_bytes()).registers().unwrap().collect();
assert_eq!(values, [555, 0, 100]);

Implementations

impl<'a> Response<'a>

pub fn new(pdu: &'a [u8]) -> Self

Wraps a response PDU for reading.

Arguments

• pdu - the response PDU, a function code followed by its data.

Returns

The response view.

pub fn function_code(&self) -> u8

Returns the function code, the first byte of the PDU.

Returns

The function code, or 0 if the PDU is empty.

pub fn exception(&self) -> Option<Exception>

Returns the exception a device reported, if this is an exception response.

Returns

The Exception if the function code’s high bit is set and a defined exception byte follows it, otherwise None.

pub fn registers(&self) -> Result<Registers<'a>, ModbusError>

Reads the 16-bit registers from a read-registers response.

Returns

An iterator over the registers in order, each decoded from its big-endian pair.

Errors

Returns ModbusError::MalformedResponse if the PDU is truncated, its declared byte count does not match its data, or that data is not a whole number of registers.

pub fn coils(&self, count: u16) -> Result<Coils<'a>, ModbusError>

Reads the coils or discrete inputs from a read-bits response.

The response packs the bits least-significant first; this unpacks exactly count of them and ignores the padding in the final byte.

Arguments

• count - how many bits to read, the quantity the request asked for.

Returns

An iterator over count bits in order.

Errors

Returns ModbusError::MalformedResponse if the PDU is truncated or its declared byte count does not match the data or the requested count.

Trait Implementations

impl<'a> Clone for Response<'a>

fn clone(&self) -> Response<'a>

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl<'a> Copy for Response<'a>

impl<'a> Debug for Response<'a>

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

Formats the value using the given formatter.