Rockwell Automation T3837 ICS Regent MODBUS Master Package for WINTERPRET - Manual (Page 4)

MODBUS Master Package for W INTERPRET (T3837)
P D - 6048 August, 96
(Issue 1) 4
Operation
The MODBUS function block uses control signals to report information and
accept runtime control directives. The signals are user defined, and may be
used like normal Regent variables. Table 1 identifies these control signals.
Table 1 - Control Signals
Name Size Type Description
E NABLE Coil Input Enables execution of the function block. Energize to
execute the function block.
E RROR Coil Output Enunciates a MODBUS function block error.
Energized when an error occurs.
R ESET Coil Input Resets the error information. Energize to reset the
information. While energized, no errors will be
reported.
N ODE Word Output The MODBUS node associated with the error. 0 when
there is no error.
C ODE Word Output The MODBUS function block error code. 0 when there
is no error.
T IME Float Output The time it took to complete the last MODBUS scan in
ms. 0 until a scan has been completed.
T OGGLE Coil Output This control signal changes state at the beginning of
each MODBUS scan. (Its period it typically 2 * Time)
E NABLE controls the execution of the function block at runtime. When
E NABLE is de-energized (OFF), the function block code is not executed
and all other signals are invalid (exception: the R ESET input signal will still be
honored).
E
RROR enunciates any errors that the MODBUS function block code
encounters.
N
ODE and C ODE are used to further define an error. They are valid only
when E RROR is active. N ODE contains the MODBUS node that is in error (
a zero [0] indicating the MODBUS master itself). C ODE contains the
specific MODBUS exception code.
The T
OGGLE state changes each time a MODBUS scan is completed. After
the initial scan, T IME contains the length (in ms) of the MODBUS scan.
T OGGLE is initialized to de-energized (OFF) for the initial scan. If a pulse is
desired instead of a toggle, external application code (in the same program)
may reset T
OGGLE to the de-energized state after a rising edge is detected.