Configuring the DATA_EXCH Management Parameter
Original instructions
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Configuring the Management Parameter
The Management parameter consists of 4 contiguous words, described below:
Data source
Register
Description
High Byte (MSB)
Low Byte (LSB)
Data managed by the system
Management_Param[0]
Exchange number
Two read-only bits:
  • Bit 0 = Activity bit (see below)
  • Bit 1 = Cancel bit
Management_Param[1]
Operation report
Communication report
Data managed by the user
Management_Param[2]
Block timeout. Values include:
  • 0 = infinite wait
  • other values = timeout x 100 ms, for example:
    • 1 = 100 ms
    • 2 = 200 ms
Management_Param[3]
Length of data sent or received:
  • Input (before sending the request): length of data in the Data_to_Send parameter, in bytes
  • Output (after response): length of data in the Received_Data parameter, in bytes
Activity Bit:
This bit indicates the execution status of the communication function.
It is set to 1 when launched, and returns to 0 when its execution is complete.
It is the first bit of the first element of the table.
Example: if the management table has been declared as follows:
Management_Param[0] ARRAY [0..3] OF INT,
the activity bit is the bit with the notation Management_Param[0].0.
NOTE: The notation previously used requires configuration of the project properties in such a way as to authorize the extraction of bits on integer types. If this is not the case, Management_Param[0].0 cannot be accessed in this manner.