Configuring Explicit Messaging Using MBP_MSTR
(Original Document)
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Overview
You can use the MBP_MSTR function block to configure Modbus TCP connected and unconnected explicit messages.
The operation begins when the input to the EN pin is turned ON. The operation ends if the ABORT pin is turned ON, or if the EN pin is turned OFF.
The CONTROL and DATABUF output parameters define the operation.
NOTE: Refer to the topic Configuring the Control Parameter for Modbus TCP for instructions on how to configure these parameters for each protocol.
The ACTIVE output turns ON during operation; the ERROR output turns ON if the operation aborts without success; the SUCCESS output turns ON at the successful completion of the operation.
EN and ENO can be configured as additional parameters.
Representation in FBD
Input Parameters
Parameter
Data type
Description
ENABLE
BOOL
When ON, the explicit message operation (specified in the first element of the CONTROL pin) is executing.
ABORT
BOOL
When ON, the operation is aborted.
Output Parameters
Parameter
Data type
Description
ACTIVE
BOOL
ON when the operation is active.
OFF at all other times.
ERROR
BOOL
ON when the operation is aborted without success.
OFF before operation, during operation, and if operation succeeds.
SUCCESS
BOOL
ON when the operation concludes successfully.
OFF before operation, during operation, and if operation does not conclude successfully.
CONTROL1
WORD
This parameter contains the control block. The first element contains a code describing the operation to be performed. The content of the control block depends on the operation. The structure of the control block depends on the protocol, in this case Modbus TCP).
Note: Assign this parameter to a located variable.
DATABUF1
WORD
This parameter contains the data buffer. For operations that:
  • provide data — e.g., a write operation — this parameter is the data source
  • receive data — e.g., a read operation — this parameter is the data destination
Note: Assign this parameter to a located variable.
1. Refer to the topic Configuring the Control Block for Modbus TCP for instructions on how to configure these parameters for the Modbus TCP communication protocol.