1.2.2 FBD/LAD Operations
New Operations Supported
You can use the operations listed in the table below in the safety program.
Operation Function Description
F-FBD F-LAD
JMP --( JMP ) Jump operation Unconditional jump in block
Jump in block if 1 (conditional)
JMPN --( JMPN ) Jump operation Jump in block if 0 (conditional)
RET --( RET ) Programmed control Return (exit block)
OV OV --| |-- Status bit Evaluate exception bit overflow (OV bit in status word)
Note
• An F_SENDDP call must not be programmed between a jump operation and
its associated destination.
• For F-PB only: A RET operation must not be programmed before a
F_SENDDP call.
!
Safety Note
If you call the following F application blocks in your safety program: F_TP, F_TON,
F_TOF, F_ACK_OP, F_2HAND, F_MUTING or F_1oo2DI and use the operations
JMP, JMPN, or RET, remember the following:
• Each call for the F application blocks listed must only be processed once in a
cycle of the F run-time group. In other words, the calls for the listed F
application blocks must not be processed more than once by the JMP or JMPN
operations (loop).
• As soon as a timer (PT, timer in F_ACK_OP, DISCTIME, DISCTIM1/2 or
TIME_MAX) starts and has not yet elapsed, a call for one of the listed F
application blocks must be processed in every cycle of the F run-time group. In
other words, the calls for the listed F application blocks must the not be
skipped by the JMP, JMPN, or RET operations (branch).
It is therefore advisable, to process the calls of the listed F application blocks
exactly once in every cycle of the F run-time group because the timers cannot be
correctly updated if this restriction is ignored.
Please note how the F application blocks work and refer to the timing diagrams
(see manual, Section 5.7.3).
Product Information for the S7 Distributed Safety, Configuring and Programming Manual
A5E00169432-02
29
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