Communication via Function Blocks
6.9 Technical Specifications of the Function Blocks
CP 341 Point-to-Point Communication, Installation and Parameter Assignment
178
Manual, 09/2008, A5E02191071-01
6.9
Technical Specifications of the Function Blocks
Memory requirements
The table below shows the memory requirements of the CP 341 function blocks/functions.
Table 6- 14 Memory requirements of the function blocks/functions in bytes
Block
Name
Version
Load memory Working memory
Local data
FC 5
V24_STAT
2.0
188
72
2
FC 6
V24_SET
2.0
156
48
2
FB 7
P_RCV_RK
2.1
3584
2982
106
FB 8
P_SND_RK
2.3
3036
2490
32
Minimum number of CPU cycles
The table below describes the minimum number of CPU cycles (FB/FC calls) required to
transact a "minimum request" (32 bytes SEND/RECEIVE for the quantity of user data
transported per program cycle). This only applies in centralized operation.
Table 6- 15 Minimum number of CPU cycles
Number of CPU cycles for processing ...
Completion without
errors
Termination with errors RESET/RESTART
P_RCV_RK
≥ 3
≥ 3
≥ 4
P_SND_RK
≥ 3
≥ 3
≥ 4
V24_STAT
1
-
-
V24_SET
2
>> 2
-
Before the CP 341 can process an activated request after the CPU has changed from STOP
to RUN mode, the CP-CPU startup mechanism P_SND_RK must have been completed. Any
requests initiated in the meantime are not lost. They are transmitted once the start-up
coordination with the CP 341 is finished.
Before the CP 341 can receive a message frame in the user program after the CPU has
changed from STOP to RUN mode, the CP-CPU startup mechanism P_RCV_RK must have
been completed.
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