
20-10
Ladder Logic (LAD) for S7-300 and S7-400
C79000-G7076-C504-02
OB1
MCRA
MCRD
MCRA
MCRA
MCRA
MCRD
BEU
BEU
Operations dependent on the MCR bit
Operations not dependent on the MCR bit
Call FBx
FBx
FCy
Call FCy
BEU BEU is an STL instruction.
You will find more details in the
Reference Manual
/102/
Figure 20-5 Activating and Deactivating an MCR Area
The operations programmed between MCRA and MCRD depend on the
signal state of the MCR bit. Operations programmed outside an
MCRA-MCRD sequence do not depend on the signal state of the MCR bit. If
an MCRD instruction is missing, the operations programmed between the
instructions MCRA and BEU depend on the MCR bit. (BEU is an STL
instruction. You will find more information in Manual /232/.)
Program Control Instructions
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