Effect Of Update Mode On Codesys Tasks; Asynchronous Update Mode; Table 199: Internal Data Bus Settings - WAGO 750-8207 Manual

Pfc200 cs 2eth rs 3g plc - controller pfc200
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WAGO-I/O-SYSTEM 750
750-8207 PFC200 CS 2ETH RS 3G

Table 199: Internal Data Bus Settings

Parameter
Update Mode
Internal Data
Bus Cycle
Time
Internal Data
Bus Thread
Priority
PLC stop
response
*
Default setting
8.9.5.1

Effect of Update Mode on CODESYS Tasks

8.9.5.1.1 Asynchronous Update Mode

In the asynchronous update mode there is no direct influence on CODESYS task
behavior.
Internal data bus "freeze" on priority conflicts!
In the asynchronous update mode there is a risk of the internal data bus
"freezing", as the internal data bus thread operates at the same priority as the
IEC tasks. The internal data bus thread must therefore use a priority higher than
that of the IEC task to prevent this from occurring.
Draft version 1.2.1 from 2017-09-13, valid from FW Version 02.06.20(09)
Explanation
The Update mode is used to configure how the internal data bus
process data is to be updated (refreshed).
In the asynchronous update mode process data
Asynchronous
are refreshed in cycles at a definable interval.
In the synchronous update mode the process
data are synchronized with the most rapid
*
Synchronous
CODESYS task that accesses the internal data
bus.
The update interval for the internal data bus is set by the cycle
time. This setting is effective only in the asynchronous mode.
1000 µs
Minimum value 1 millisecond
*
10000 µs
Default value 10 milliseconds
50000 µs
Maximum value 50 milliseconds
This value indicates the priority for the internal data bus thread.
This setting is effective only in the asynchronous mode.
This priority is equivalent to the priority of the cyclic CODESYS
tasks (see Section "Cyclic Tasks").
This setting is effective only in the asynchronous mode.
*
0
Highest priority
15
Lowest priority
Specifies the response of the internal data bus outputs when the
PLC application stops.
Hold last value The output states are retained.
*
Set to zero
Outputs are set to zero.
Run-time System CODESYS 2.3 261
Manual

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