send_dataT_send_dataSendDataSendData (Operator)

Name

send_dataT_send_dataSendDataSendData — Send arbitrary data to external devices or applications using a generic socket communication.

Signature

send_data( : : Socket, Format, Data, To : )

send_datasend_dataSendDataSendDataSendData sends arbitrary data over a socket connection. The sent data is converted to a binary network packet from a value (or a tuple of values) using the parameter FormatFormatFormatFormatformat as specification and is well-suited to communicate with external devices or applications. This operator does not support the standard 'HALCON'"HALCON""HALCON""HALCON""HALCON" protocol, but is intended for arbitrary data transfer.

The parameter FormatFormatFormatFormatformat specifies how to convert the given tuples to a binary packet. It uses one or multiple qualifier characters each followed by an optional modifier and repeat count. Most qualifiers require a single value in the DataDataDataDatadata parameter which will be converted.

The following characters are allowed in this format string:

Integer values:

'c':: one byte = 8 bit, signed
'C':: same as 'c' but unsigned
's':: two bytes = 16 bit, signed
'S':: same as 's' but unsigned
'i':: four bytes = 32 bit, signed
'I':: same as 'i' but unsigned
'q':: eight bytes = 64 bit, signed (only available on 64bit architectures)
'Q':: same as 'q' but unsigned

Float values:

'f':: float, 4 bytes = 32 bit
'd':: double, 8 bytes = 64 bit

String values:

'A':: string (default length 1024 bytes), padded with spaces
'Z':: string (default length 1024 bytes), padded with zeros and will be zero terminated when sending
'z':: string with variable length, the length modifier specifies the maximum length (default length 1024 bytes)

Special characters which do not require a value as DataDataDataDatadata parameter:

'-':: a single byte is written as binary zero or when reading, a zero byte is skipped
'_':: a single byte is written as space (binary 0x20) or when reading, a space byte is skipped
' ':: ignored, can be used to enhance readability of the format string

Modifiers which can be used after one of the qualifiers above:

'n':: convert the integer or float value when writing to or when reading from network byte order (big endian) to host byte order
'N':: convert the integer or float value when writing to or when reading from intel byte order (little endian) to host byte order
'0-n':: specify a repeat count for the preceding qualifier, e.g., 'c5' means the same as 'ccccc' (and requires therefore a tuple of 5 values) but 'A10' means a string with a size of 10 bytes (and requires only one value)

The modifiers 'n' and 'N' can also be used as first character in the format string and set the default byte order. 'n', which means network byte order, is the default byte order when nothing else is specified.

For UDP connections the binary data must be transferred in one network packet so that the size of the binary data must not be bigger than one network packet. Usually this means it should be smaller than the MTU (maximum transfer unit) of the interface, which is usually about 1500 bytes, but only 576 bytes are guaranteed (1280 bytes for IPv6).

The parameter ToToToToto should be left empty for socket connections that are already bound (all TCP connections and bound UDP connections), but in case of an unbound UDP connection it must be used to specify the IP address or host name and port number of the communication partner.