X20 system modules • Analog input modules • X20AI2438
232
X20 system User's Manual 3.10
Message larger than the OutputMTU:
The transmit array, which needs to be created in the program sequence, consists of several elements. The user
has to arrange the control and data bytes correctly and transfer the array elements one after the other. The transfer
algorithm remains the same and is repeated starting at the point
Cyclic checks
.
General flow chart:
Synchronization
Sequence handling
No
No
Yes
Yes
Yes
No
No
Yes
No
No
Yes
Yes
(diff <= limit)
AND (OutputSyncAck = 1)
AND (OutputSyncBit = 1) ?
Copy next sequence to MTU
Increase OutputSequenceCounter
OutputSequenceAck =
OutputSequenceCounter?
OutputSequenceAck = 0?
OutputSequenceCounter = 1
OutputSyncBit = 1
OutputSequenceCounter = 0
LastValidAck = 0
LastValidAck =
OutputSequenceAck
LastValidAck =
OutputSequenceCounter?
More sequences to be sent?
diff = 0?
LastValidAck =
OutputSequenceAck
Start
►
►
diff = (OutputSequenceCounter -
OutputSequenceAck) AND 7
limit = (OutputSequenceCounter -
LastValidAck) AND 7
Figure 78: Flow chart for the output direction