Case 3: Codesys Task Interval Greater Than Twice The Internal Data Bus Cycle; Figure 94: I/O Module Synchronization 03 - WAGO I/O SYSTEM 750 Manual

246 Run-time System CODESYS 2.3
8.9.3 Case 3: CODESYS Task Interval Greater than Twice the
Internal Data Bus Cycle
The I/O data from the internal data bus are refreshed once prior to the CODESYS
task and once after the CODESYS task.
Prior to processing the CODESYS task, the internal data bus cycle is executed,
which provides the current input data for the CODESYS task. After execution of
the CODESYS task, an additional internal data bus cycle is started, which
provides the output data to the I/O modules.
This ensures that at the start of every CODESYS task, current input data are
available from the internal data bus and the output data from each CODESYS task
are quickly output to the I/O modules. This prevents processing of internal data
bus cycles that would unnecessarily use a great deal of computing time on the
CPU.

Figure 94: I/O Module Synchronization 03

CTI: CODESYS Task Interval
CT: CODESYS Task that accesses the I/O module of the internal data bus
KBZ: Internal Data Bus Cycle
Example:
CODESYS task interval (CTI): 5000 µs
Internal data bus cycle (KBZ): 2000 µs
Result: Execution of the internal data bus cycle 2000 µs prior to the CODESYS
task and once directly after the CODESYS task.
750-8208 PFC200 CS 2ETH RS CAN DPM
Version 1.1.0, valid from FW Version 02.06.20(09)
WAGO-I/O-SYSTEM 750
Manual