Introduction

The structure and content of the management parameter of the DATA_EXCH block is common to both EtherNet/IP and Modbus TCP explicit messaging.

Configuring the Management Parameter

The management parameter consists of four contiguous words:

Data source

Register

Description

High Byte (MSB)

Low Byte (LSB)

Data managed by the system

Management_Param[0]

Exchange number

Two read-only bits:

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

The activity bit is the first bit of the first element in the table. The value of this bit indicates the execution status of the communication function:

  • 1: The bit is set to 1 when the function launches.

  • 0: The bit returns to 0 upon the completion of the execution. (The transition from 1 to 0 increments the exchange number. If an error is detected during the execution, search for the corresponding code in the operation and communication report.)

For example, you can make this declaration in the management table:

Management_Param[0] ARRAY [0..3] OF INT

For that declaration, the activity bit corresponds to this 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.