WAGO I/O SYSTEM 750 XTR
Run-time System CODESYS 2.3 271
750-8202/040-001 PFC200 2ETH RS TELE XTR
Manual
Version 1.2.0, valid from FW Version 03.01.07(13)
8.9.3
Case 3: CODESYS Task Interval Greater than Twice the
Local Bus Cycle
The I/O data from the local bus are refreshed once prior to the CODESYS task
and once after the CODESYS task.
Prior to processing the CODESYS task, the local bus cycle is executed, which
provides the current input data for the CODESYS task. After execution of the
CODESYS task, an additional local 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 local bus and the output data from each CODESYS task are
quickly output to the I/O modules. This prevents processing of local bus cycles
that would unnecessarily use a great deal of computing time on the CPU.
Figure 88: Local Bus Synchronization (Case 3)
CTI: CODESYS Task Interval
CT: CODESYS Task that accesses the I/O modules via the local bus
LBZ: Local Bus Cycle
Example:
CODESYS task interval (CTI): 5000 µs
Local bus cycle (LBZ): 2000 µs
Result:
Execution of the local bus cycle 2000 µs prior to the CODESYS task and
once directly after the CODESYS task.
