quanser.communications.stream Class

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The quanser.communications.stream class provides methods to communicate betweeen local and remote systems or devices. It provides a uniform interface for communications such as TCP/IP, UDP, shared memory, serial, SPI, I2C, etc. A communication channel is represented by a "stream", which can be a server, or listening stream, that accepts connections from clients, or a client that connects to a server or device.

To create a listening stream to act as a server, use the static quanser.communications.stream.listen method. The listen function returns an instance of the stream class whose accept method may then be used to accept a connection from a client. When the stream is no longer needed it should be closed using the close method.

To create a stream to act as a client, use the static quanser.communications.stream.connect method. The connect function returns an instance of the stream class whose methods may then be used to send and receive data from the server. When the stream is no longer needed it should be closed using the close method.

The methods of the stream class may be grouped into the following categories:

Static functions
Configuration functions
State functions
Send functions
Receive functions

To build and run scripts involving communications in real-time on Quanser targets, refer to the Basic Procedures for Scripts.

Static Functions

The quanser.communications.stream class has the following static functions:

quanser.communications.stream.connect	Creates a stream acting as a client that connects to a server.
quanser.communications.stream.listen	Creates a listening stream to act as a server which can receive client connections.
quanser.communications.stream.close_all	Closes all open streams.

Configuration Functions

Once the board is open, the configuration functions are used to configure features of the stream, such as getting or setting the byte order or character format.

The following methods of the stream instance may be used to configure the stream:

get_character_format	Gets the character format of the stream.
set_character_format	Sets the character format of the stream.
set_byte_order	Sets the byte order used by the stream for multibyte data types.

State Functions

Once the board is open, the state functions are used to accept a client connection over a listening stream or poll the state of the stream.

The following methods of the stream instance may be used to query the state of the stream:

accept	Accepts a client connection over a listening stream.
poll	Polls the state of the stream.

Send Functions

The send functions send data over the communication channel. For multi-byte data types, the byte order configured for the stream determines the order in which the bytes of the data type are sent.

Note that the send functions store the data in the stream send buffer and the data is only sent over the communication channel when the buffer is full or the flush method is called.

The send functions are as follows:

flush	Flushes the contents of the stream send buffer to the underlying communication channel.
send_double	Sends a 64-bit floating-point number over the stream.
send_doubles	Sends an array of 64-bit floating-point numbers over the stream.
send_double_array	Sends an array of 64-bit floating-point numbers as an atomic unit over the stream.
send_single	Sends a 32-bit floating-point number over the stream.
send_singles	Sends an array of 32-bit floating-point numbers over the stream.
send_single_array	Sends an array of 32-bit floating-point numbers as an atomic unit over the stream.
send_int8	Sends an 8-bit integer over the stream.
send_int8s	Sends an array of 8-bit integers over the stream.
send_int8_array	Sends an array of 8-bit integers as an atomic unit over the stream.
send_uint8	Sends an 8-bit unsigned integer over the stream.
send_uint8s	Sends an array of 8-bit unsigned integers over the stream.
send_uint8_array	Sends an array of 8-bit unsigned integers as an atomic unit over the stream.
send_int16	Sends a 16-bit integer over the stream.
send_int16s	Sends an array of 16-bit integers over the stream.
send_int16_array	Sends an array of 16-bit integers as an atomic unit over the stream.
send_uint16	Sends a 16-bit unsigned integer over the stream.
send_uint16s	Sends an array of 16-bit unsigned integers over the stream.
send_uint16_array	Sends an array of 16-bit unsigned integers as an atomic unit over the stream.
send_int32	Sends a 32-bit integer over the stream.
send_int32s	Sends an array of 32-bit integers over the stream.
send_int32_array	Sends an array of 32-bit integers as an atomic unit over the stream.
send_uint32	Sends a 32-bit unsigned integer over the stream.
send_uint32s	Sends an array of 32-bit unsigned integers over the stream.
send_uint32_array	Sends an array of 32-bit unsigned integers as an atomic unit over the stream.
send_int64	Sends a 64-bit integer over the stream.
send_int64s	Sends an array of 64-bit integers over the stream.
send_int64_array	Sends an array of 64-bit integers as an atomic unit over the stream.
send_uint64	Sends a 64-bit unsigned integer over the stream.
send_uint64s	Sends an array of 64-bit unsigned integers over the stream.
send_uint64_array	Sends an array of 64-bit unsigned integers as an atomic unit over the stream.
print	Prints formatted text to a stream.
print_array	Prints formatted text to a stream as an atomic unit.

Receive Functions

The receive functions receive data over the communication channel. For multi-byte data types, the byte order configured for the stream determines the order in which the bytes of the data type are received.

The receive functions are as follows:

ignore	Receives bytes over the stream and ignores them.
receive_double	Receives a 64-bit floating-point number over the stream.
receive_doubles	Receives an array of 64-bit floating-point numbers over the stream.
receive_double_array	Receives an array of 64-bit floating-point numbers as an atomic unit over the stream.
receive_single	Receives a 32-bit floating-point number over the stream.
receive_singles	Receives an array of 32-bit floating-point numbers over the stream.
receive_single_array	Receives an array of 32-bit floating-point numbers as an atomic unit over the stream.
receive_int8	Receives an 8-bit integer over the stream.
receive_int8s	Receives an array of 8-bit integers over the stream.
receive_int8_array	Receives an array of 8-bit integers as an atomic unit over the stream.
receive_uint8	Receives an 8-bit unsigned integer over the stream.
receive_uint8s	Receives an array of 8-bit unsigned integers over the stream.
receive_uint8_array	Receives an array of 8-bit unsigned integers as an atomic unit over the stream.
receive_int16	Receives a 16-bit integer over the stream.
receive_int16s	Receives an array of 16-bit integers over the stream.
receive_int16_array	Receives an array of 16-bit integers as an atomic unit over the stream.
receive_uint16	Receives a 16-bit unsigned integer over the stream.
receive_uint16s	Receives an array of 16-bit unsigned integers over the stream.
receive_uint16_array	Receives an array of 16-bit unsigned integers as an atomic unit over the stream.
receive_int32	Receives a 32-bit integer over the stream.
receive_int32s	Receives an array of 32-bit integers over the stream.
receive_int32_array	Receives an array of 32-bit integers as an atomic unit over the stream.
receive_uint32	Receives a 32-bit unsigned integer over the stream.
receive_uint32s	Receives an array of 32-bit unsigned integers over the stream.
receive_uint32_array	Receives an array of 32-bit unsigned integers as an atomic unit over the stream.
receive_int64	Receives a 64-bit integer over the stream.
receive_int64s	Receives an array of 64-bit integers over the stream.
receive_int64_array	Receives an array of 64-bit integers as an atomic unit over the stream.
receive_uint64	Receives a 64-bit unsigned integer over the stream.
receive_uint64s	Receives an array of 64-bit unsigned integers over the stream.
receive_uint64_array	Receives an array of 64-bit unsigned integers as an atomic unit over the stream.
scan	Scans formatted text from a stream.
scan_array	Scans formatted text from a stream as an atomic unit.

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