ModbusRtuInterface Class

Namespace: GHIElectronics.TinyCLR.Devices.Modbus.Interface · Assembly: GHIElectronics.TinyCLR.Devices.Modbus

ModbusRtuInterface is a Modbus RTU implemention of the IModbusInterface interface to be used with ModbusMaster or ModbusDevice.

public class ModbusRtuInterface : IModbusInterface

Constructors

ModbusRtuInterface(UartController serial, int baudRate, int dataBits, UartStopBitCount stopBits, UartParity parity, short maxDataLength)

public ModbusRtuInterface(UartController serial, int baudRate, int dataBits, UartStopBitCount stopBits, UartParity parity, short maxDataLength = 252)

Creates a new Modbus RTU interface using an existing and fully initialized UartController. This interface can be used with ModbusMaster or ModbusDevice.

Parameter	Type	Description
serial	UartController	Fully initialized UartController.
baudRate	int
dataBits	int
stopBits	UartStopBitCount
parity	UartParity
maxDataLength	short	Maximum number of data bytes

Properties

UartController

public UartController UartController { get; }

Gets the serial port which is used.

MaxDataLength

public short MaxDataLength { get; set; }

Gets the maximum data length (not including address, function code, ...) of e telegram.

MaxTelegramLength

public short MaxTelegramLength { get; set; }

Gets the maximum length of a Modbus telegram.

IsDataAvailable

public bool IsDataAvailable { get; }

Gets if there is currently dataavailable on the interface.

IsConnectionOk

public bool IsConnectionOk { get; }

Gets if the connection is ok

Methods

CreateTelegram(byte addr, byte fkt, short dataLength, byte[] buffer, out short telegramLength, out short dataPos, bool isResponse, ref object telegramContext)

public void CreateTelegram(byte addr, byte fkt, short dataLength, byte[] buffer, out short telegramLength, out short dataPos, bool isResponse, ref object telegramContext)

Creates a new telegram for a modbus request or response. All data except the function code specific user data is written into the given buffer.

Parameter	Type	Description
addr	byte	Device address. 0 = Breadcast, 1..247 are valid device addresses.
fkt	byte	Function code. ModbusFunctionCode
dataLength	short	Number of bytes for function code sspecific user data.
buffer	byte[]	Buffer to write data into. The buffer must be at least MaxTelegramLength - MaxDataLength + dataLength bytes long.
telegramLength	out short	Returns the total length of the telegram in bytes.
dataPos	out short	Returns the offset of the function code specific user data in buffer.
isResponse	bool	true if this is a response telegram; false if this is a request telegram.
telegramContext	ref object	If isResponse == false, this parameter returns the interface implementation specific data which must be passed to the ParseTelegram method of the received response. If isResponse == true, this parameter must be called with the telegramContext parameter returned by ParseTelegram of the request telegram.

PrepareWrite()

public void PrepareWrite()

No description available.

PrepareRead()

public void PrepareRead()

No description available.

SendTelegram(byte[] buffer, short telegramLength)

public void SendTelegram(byte[] buffer, short telegramLength)

Sends the given telegram. If necessary additional information like a checksum can be inserted here.

Parameter	Type	Description
buffer	byte[]	Buffer containing the data.
telegramLength	short	Length of the telegram in bytes.

ReceiveTelegram(byte[] buffer, short desiredDataLength, int timeout, out short telegramLength)

public bool ReceiveTelegram(byte[] buffer, short desiredDataLength, int timeout, out short telegramLength)

Waits and receives a telegram.

Parameter	Type	Description
buffer	byte[]	Buffer to write data into.
desiredDataLength	short	Desired length of the function code specific data in bytes. -1 if length is unknown.
timeout	int	Timeout in milliseconds to wait for the telegram.
telegramLength	out short	Returns the total length of the telegram in bytes.

Returns bool — Returns true if the telegram was received successfully; false on timeout.

ParseTelegram(byte[] buffer, short telegramLength, bool isResponse, ref object telegramContext, out byte address, out byte fkt, out short dataPos, out short dataLength)

public bool ParseTelegram(byte[] buffer, short telegramLength, bool isResponse, ref object telegramContext, out byte address, out byte fkt, out short dataPos, out short dataLength)

Parses a telegram received by ReceiveTelegram.

Parameter	Type	Description
buffer	byte[]	Buffer containing the data.
telegramLength	short	Total length of the telegram in bytes.
isResponse	bool	true if the telegram is a response telegram; false if the telegram is a request telegram.
telegramContext	ref object	If isResponse == true: pass the telegramContext returned by CreateTelegram from the request. If isResponse == false: returns the telegramContext from the received request. It must pe passed to the CreateTelegram method for the response.
address	out byte	Returns the device address.
fkt	out byte	Returns the function code.
dataPos	out short	Returns the offset in buffer of the function code specific data.
dataLength	out short	Returns the length of the function code specific data.

Returns bool — Returns true if this is the matching response according to the telegramContext; else false. If isResponse == false this method should return always true.

ClearInputBuffer()

public void ClearInputBuffer()

Removes all data from the input interface.

Fields

isOpen

public bool isOpen

No description available.