Rockwell Automation T3837 ICS Regent MODBUS Master Package for WINTERPRET - Manual (Page 3)

MODBUS Master Package for W INTERPRET (T3837)
P D - 6048 August, 96
(Issue 1) 3
time it is called, the MODBUS Master function block code splits up the
tasks so that it can be done a little at
a time. This allows the Regent system to remain responsive, as well as
eliminating the potential loss of time while waiting for MODBUS responses.
For an overview about Regent application programs and function blocks
and how to create them using W
INTERPRET , refer to Section 5, Working
with Programs and Function Blocks, in the Regent User’s Guide.
Using MODBUS Master Function Blocks
The MODBUS Master function block allows the user to specify the
following Regent variables:
· Variables to receive data from MODBUS slaves
· Variables to be the source of data sent to MODBUS slaves
· Variables to serve as control signals for the function block
· Variables to receive the current status and other information about the
function block.
Each Regent variable used to send or receive data may be associated with a
different MODBUS node and address. The user may specify which port on
the Regent to use, including the selection of a secondary port for a dual-link
configuration.
The MODBUS Master function block compiler may be invoked from the
File menu in the MODBUS function block editor when the editor is closed
and the changes have been saved for the current function block. The
compiler translates the user’s inputs from the source file into an object file to
be loaded into and executed in the Regent.
The compiler has two separate phases: registration and generation. In the
registration phase, the compiler registers tag names and retrieves definitions
from the project dictionary. The generation phase consists of parameter
validation followed by code and data segments generation. The registration
phase follows the conventions (and requirements) imposed by other
W
INTERPRET function block compilers. The generation phase is unique to
each function block compiler, and is where MODBUS-Master-specific
code is introduced.