Specifications

RS-232 Simulink Block Reference
2-29
RS-232 Send/Receive Block (Synchronous)
The Block Parameters dialog box for the Synchronous Send & Receive
block contains the following fields.
Parameter Description
Port From the list, choose COM1, COM2, COM3, or COM4. This
list allows you to define which COM port is used to send and
receive the data. The model must contain one Setup block
for the same COM port used to send and receive data.
Otherwise, an error message is displayed. Note that data is
sent and received on the same COM port.
Message
Structure
Name
Enter the name of the MATLAB structure this block uses to
send and receive messages and data to an RS-232 device.
For information to create this structure, see “Creating
RS-232 Message Structures (Synchronous)” on page 2-13.
Sample
Time
This entry allows you to define the sample time of the block.
Since this block waits for data to be received from the
RS-232 external device before the block is finished
executing, small sample times are not suitable with
Synchronous Mode. You must allow sufficient time for
both the RS232 send and the RS232 receive operations to be
completed. The smallest sample time depends on the
following.
•Amount of data being sent
•Amount of data being received
•Selected baud rate
•Response time of the external device