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use failure::Error; use libc::{c_char, c_int}; use libmodbus_sys as ffi; use modbus::Modbus; use std::ffi::CString; use std::str; #[derive(Debug, PartialEq)] #[allow(non_camel_case_types)] pub enum SerialMode { RtuRS232 = ffi::MODBUS_RTU_RS232 as isize, RtuRS485 = ffi::MODBUS_RTU_RS485 as isize, } #[derive(Debug, PartialEq)] pub enum RequestToSendMode { RtuRtsNone = ffi::MODBUS_RTU_RTS_NONE as isize, RtuRtsUp = ffi::MODBUS_RTU_RTS_UP as isize, RtuRtsDown = ffi::MODBUS_RTU_RTS_DOWN as isize, } /// The RTU backend (Remote Terminal Unit) is used in serial communication and makes use of a compact, binary /// representation of the data for protocol communication. /// The RTU format follows the commands/data with a cyclic redundancy check checksum as an error check mechanism to /// ensure the reliability of data. /// Modbus RTU is the most common implementation available for Modbus. A Modbus RTU message must be transmitted /// continuously without inter-character hesitations /// (extract from Wikipedia, Modbus, http://en.wikipedia.org/wiki/Modbus (as of Mar. 13, 2011, 20:51 GMT). /// /// The Modbus RTU framing calls a slave, a device/service which handle Modbus requests, and a master, a client which /// send requests. The communication is always initiated by the master. /// /// Many Modbus devices can be connected together on the same physical link so before sending a message, you must set /// the slave (receiver) with modbus_set_slave(3). /// If you’re running a slave, its slave number will be used to filter received messages. /// /// The libmodbus implementation of RTU isn’t time based as stated in original Modbus specification, /// instead all bytes are sent as fast as possible and a response or an indication is considered complete when all /// expected characters have been received. /// This implementation offers very fast communication but you must take care to set a response timeout of slaves less /// than response timeout of master /// (ortherwise other slaves may ignore master requests when one of the slave is not responding). /// /// * Create a Modbus RTU context /// - [`new_rtu()`](struct.Modbus.html#method.new_rtu) /// /// * Set the serial mode /// - [`rtu_get_serial_mode()`](struct.Modbus.html#method.rtu_get_serial_mode), /// [`rtu_set_serial_mode()`](struct.Modbus.html#method.rtu_set_serial_mode), /// [`rtu_get_rts()`](struct.Modbus.html#method.rtu_get_rts), [`rtu_set_rts()`](struct.Modbus.html#method.rtu_set_rts), /// [`rtu_set_custom_rts()`](struct.Modbus.html#method.rtu_set_custom_rts), /// [`rtu_get_rts_delay()`](struct.Modbus.html#method.rtu_get_rts_delay), /// [`rtu_set_rts_delay()`](struct.Modbus.html#method.rtu_set_rts_delay) /// pub trait ModbusRTU { fn new_rtu(device: &str, baud: i32, parity: char, data_bit: i32, stop_bit: i32) -> Result<Modbus, Error>; fn rtu_get_serial_mode(&self) -> Result<SerialMode, Error>; fn rtu_set_serial_mode(&mut self, mode: SerialMode) -> Result<(), Error>; fn rtu_get_rts(&self) -> Result<RequestToSendMode, Error>; fn rtu_set_rts(&mut self, mode: RequestToSendMode) -> Result<(), Error>; fn rtu_set_custom_rts(&mut self, _mode: RequestToSendMode) -> Result<i32, Error>; fn rtu_get_rts_delay(&self) -> Result<i32, Error>; fn rtu_set_rts_delay(&mut self, us: i32) -> Result<(), Error>; } impl ModbusRTU for Modbus { /// `new_rtu` - create a libmodbus context for RTU /// /// The [`new_rtu()`](#method.new_rtu) function shall allocate and initialize a structure /// to communicate in RTU mode on a serial line. /// /// The **device** argument specifies the name of the serial port handled by the OS, eg. "/dev/ttyS0" or /// "/dev/ttyUSB0". /// On Windows, it’s necessary to prepend COM name with "\\.\" for COM number greater than 9, /// eg. "\\\\.\\COM10". See http://msdn.microsoft.com/en-us/library/aa365247(v=vs.85).aspx for details /// The **baud** argument specifies the baud rate of the communication, eg. 9600, 19200, 57600, 115200, etc. /// /// The **parity** argument can have one of the following values: /// * N for none /// * E for even /// * O for odd /// /// The **data_bits argument** specifies the number of bits of data, the allowed values are 5, 6, 7 and 8. /// The **stop_bits** argument specifies the bits of stop, the allowed values are 1 and 2. /// Once the modbus structure is initialized, you must set the slave of your device with /// [`set_slave()`](#method.set_slave) and connect to the serial bus with [`connect()`](#method.connect). /// /// # Examples /// /// ``` /// use libmodbus_rs::{Modbus, ModbusRTU}; /// /// const YOUR_DEVICE_ID: u8 = 1; /// let mut modbus = Modbus::new_rtu("/dev/ttyUSB0", 115200, 'N', 8, 1).unwrap(); /// modbus.set_slave(YOUR_DEVICE_ID); /// /// match modbus.connect() { /// Ok(_) => { } /// Err(e) => println!("Error: {}", e), /// } /// ``` fn new_rtu(device: &str, baud: i32, parity: char, data_bit: i32, stop_bit: i32) -> Result<Modbus, Error> { unsafe { let device = CString::new(device).unwrap(); let ctx = ffi::modbus_new_rtu(device.as_ptr(), baud as c_int, parity as c_char, data_bit as c_int, stop_bit as c_int); if ctx.is_null() { bail!(::std::io::Error::last_os_error()) } else { Ok(Modbus { ctx: ctx }) } } } /// `rtu_get_serial_mode` - get the current serial mode /// /// The [`rtu_get_serial_mode()`](#method.rtu_get_serial_mode) function shall return the serial mode currently /// used by the libmodbus context: /// /// `SerialMode::RtuRS232` /// the serial line is set for RS232 communication. RS-232 (Recommended Standard 232) /// is the traditional name for a series of standards for serial binary single-ended /// data and control signals connecting between a DTE (Data Terminal Equipment) and a /// DCE (Data Circuit-terminating Equipment). It is commonly used in computer serial ports /// /// `SerialMode::RtuRS485` /// the serial line is set for RS485 communication. /// EIA-485, also known as TIA/EIA-485 or RS-485, is a standard defining the electrical /// characteristics of drivers and receivers for use in balanced digital multipoint systems. /// This standard is widely used for communications in industrial automation because it can be /// used effectively over long distances and in electrically noisy environments. /// /// This function is only available on Linux kernels 2.6.28 onwards /// and can only be used with a context using a RTU backend. /// /// # Examples /// /// ``` /// use libmodbus_rs::{Modbus, ModbusRTU, SerialMode}; /// /// let modbus = Modbus::new_rtu("/dev/ttyUSB0", 115200, 'N', 8, 1).unwrap(); /// /// assert_eq!(modbus.rtu_get_serial_mode().unwrap(), SerialMode::RtuRS232); /// ``` fn rtu_get_serial_mode(&self) -> Result<SerialMode, Error> { unsafe { let mode = ffi::modbus_rtu_get_serial_mode(self.ctx); match mode { mode if mode == SerialMode::RtuRS232 as i32 => Ok(SerialMode::RtuRS232), mode if mode == SerialMode::RtuRS485 as i32 => Ok(SerialMode::RtuRS485), _ => bail!(::std::io::Error::last_os_error()), } } } /// `rtu_set_serial_mode` - set the serial mode /// /// The [`rtu_set_serial_mode()`](#method.rtu_set_serial_mode) function shall set the selected serial mode: /// /// `RTU_RS232` /// the serial line is set for RS232 communication. /// RS-232 (Recommended Standard 232) is the traditional name for a series of /// standards for serial binary single-ended data and control signals connecting /// between a DTE (Data Terminal Equipment) and a DCE (Data Circuit-terminating Equipment). /// It is commonly used in computer serial ports /// /// `RTU_RS485` /// the serial line is set for RS485 communication. /// EIA-485, also known as TIA/EIA-485 or RS-485, is a standard defining the /// electrical characteristics of drivers and receivers for use in balanced digital multipoint systems. /// This standard is widely used for communications in industrial automation /// because it can be used effectively over long distances and in electrically noisy environments. /// /// This function is only supported on Linux kernels 2.6.28 onwards. /// /// # Return value /// /// The function return an OK Result if successful. Otherwise it contains an Error. /// /// # Examples /// /// ``` /// use libmodbus_rs::{Modbus, ModbusRTU, SerialMode}; /// let mut modbus = Modbus::new_rtu("/dev/ttyUSB0", 115200, 'N', 8, 1).unwrap(); /// /// assert!(modbus.rtu_set_serial_mode(SerialMode::RtuRS232).is_ok()); /// ``` fn rtu_set_serial_mode(&mut self, mode: SerialMode) -> Result<(), Error> { unsafe { let mode = ffi::modbus_rtu_set_serial_mode(self.ctx, mode as c_int) as i32; match mode { -1 => bail!(::std::io::Error::last_os_error()), 0 => Ok(()), _ => panic!("libmodbus API incompatible response"), } } } /// `rtu_set_rts` - set the RTS mode in RTU /// /// The [`rtu_set_rts()`](#method.rtu_set_rts) function shall set the Request To Send mode to communicate on a /// RS485 serial bus. /// By default, the mode is set to `RequestToSendMode::RtuRtsNone` and no signal is issued before writing /// data on the wire. /// /// To enable the RTS mode, the values `RequestToSendMode::RtuRtsUp` or /// `RequestToSendMode::RtuRtsDown` must be used, /// these modes enable the RTS mode and set the polarity at the same time. When /// `RequestToSendMode::RtuRtsUp` is used, /// an ioctl call is made with RTS flag enabled then data is written on the bus after a delay of 1 ms, /// then another ioctl call is made with the RTS flag disabled and again a delay of 1 ms occurs. /// The `RequestToSendMode::RtuRtsDown` mode applies the same procedure but with an inverted RTS flag. /// /// This function can only be used with a context using a RTU backend. /// /// # Examples /// /// ``` /// use libmodbus_rs::{Modbus, ModbusRTU, SerialMode, RequestToSendMode}; /// let mut modbus = Modbus::new_rtu("/dev/ttyUSB0", 115200, 'N', 8, 1).unwrap(); /// /// let serial_mode = modbus.rtu_set_serial_mode(SerialMode::RtuRS485); /// /// assert!(modbus.rtu_set_rts(RequestToSendMode::RtuRtsUp).is_ok()); /// ``` fn rtu_set_rts(&mut self, mode: RequestToSendMode) -> Result<(), Error> { unsafe { match ffi::modbus_rtu_set_rts(self.ctx, mode as c_int) { -1 => bail!(::std::io::Error::last_os_error()), 0 => Ok(()), _ => panic!("libmodbus API incompatible response"), } } } /// `rtu_get_rts` - get the current RTS mode in RTU /// /// The [`rtu_get_rts()`](#method.rtu_get_rts) function shall get the current Request To Send mode of the libmodbus /// context ctx. The possible returned values are: /// * MODBUS_RTU_RTS_NONE /// * MODBUS_RTU_RTS_UP /// * MODBUS_RTU_RTS_DOWN /// /// This function can only be used with a context using a RTU backend. /// /// # Examples /// /// ```no_run /// use libmodbus_rs::{Modbus, ModbusRTU, SerialMode}; /// let mut modbus = Modbus::new_rtu("/dev/ttyUSB0", 115200, 'N', 8, 1).unwrap(); /// /// assert!(modbus.rtu_set_serial_mode(SerialMode::RtuRS485).is_ok()); /// ``` fn rtu_get_rts(&self) -> Result<RequestToSendMode, Error> { unsafe { let mode = ffi::modbus_rtu_get_rts(self.ctx) as u32; match mode { ffi::MODBUS_RTU_RTS_NONE => Ok(RequestToSendMode::RtuRtsNone), ffi::MODBUS_RTU_RTS_UP => Ok(RequestToSendMode::RtuRtsUp), ffi::MODBUS_RTU_RTS_DOWN => Ok(RequestToSendMode::RtuRtsDown), _ => bail!(::std::io::Error::last_os_error()), } } } /// `rtu_set_custom_rts` - set a function to be used for custom RTS implementation /// /// The modbus_rtu_set_custom_rts() function shall set a custom function to be called when the RTS pin is to be set /// before and after a transmission. By default this is set to an internal function that toggles the RTS pin using /// an ioctl call. /// /// Note that this function adheres to the RTS mode, /// the values MODBUS_RTU_RTS_UP or MODBUS_RTU_RTS_DOWN must be used for the function to be called. /// /// This function can only be used with a context using a RTU backend. /// /// TODO: implement rtu_set_custom_rts()! fn rtu_set_custom_rts(&mut self, _mode: RequestToSendMode) -> Result<i32, Error> { unimplemented!() } /// `rtu_get_rts_delay` - get the current RTS delay in RTU /// /// The [`rtu_get_rts_delay()`](#method.rtu_get_rts_delay) function shall get the current /// Request To Send delay period of the libmodbus context ctx. /// /// This function can only be used with a context using a RTU backend. /// /// # Return value /// /// The [`rtu_get_rts_delay()`](#method.rtu_get_rts_delay) function shall return the current RTS delay in /// microseconds /// if successful. Otherwise it shall return `ModbusError::NotRTU`. /// /// # Examples /// /// ``` /// use libmodbus_rs::{Modbus, ModbusRTU}; /// let modbus = Modbus::new_rtu("/dev/ttyUSB0", 115200, 'N', 8, 1).unwrap(); /// /// modbus.rtu_get_rts_delay(); /// ``` fn rtu_get_rts_delay(&self) -> Result<i32, Error> { unsafe { match ffi::modbus_rtu_get_rts_delay(self.ctx) { -1 => bail!(::std::io::Error::last_os_error()), delay => Ok(delay), } } } /// `rtu_set_rts_delay` - get the current RTS delay in RTU /// /// The [`rtu_set_rts_delay()`](#method.rtu_set_rts_delay) function shall set the Request To Send delay period of /// the libmodbus context. /// /// This function can only be used with a context using a RTU backend. /// /// # Return value /// /// The [`rtu_set_rts_delay()`](#method.rtu_set_rts_delay) function return an OK Result if successful. Otherwise it /// contains an Error. /// /// # Examples /// /// ``` /// use libmodbus_rs::{Modbus, ModbusRTU}; /// let mut modbus = Modbus::new_rtu("/dev/ttyUSB0", 115200, 'N', 8, 1).unwrap(); /// /// let _ = modbus.rtu_set_rts_delay(100).unwrap(); /// ``` fn rtu_set_rts_delay(&mut self, us: i32) -> Result<(), Error> { unsafe { match ffi::modbus_rtu_set_rts_delay(self.ctx, us as c_int) { -1 => bail!(::std::io::Error::last_os_error()), 0 => Ok(()), _ => panic!("libmodbus API incompatible response"), } } } }