Specifications

SIMATIC Instructions
9-154
S7-200 Programmable Controller System Manual
C79000-G7076-C233-01
BEFORE
LSCR
Load the value of Sx.y onto the SCR and logic stacks.
iv0
iv1
iv2
iv3
iv4
iv5
iv6
iv7
iv8
Sx.y
iv1
iv2
iv3
iv4
iv5
iv6
iv7
iv8
Sx.y
AFTER
S stack Logic stack
initial value
of S
S bit
ivs
S stack Logic stack
Figure 9-57 Effect of LSCR on the Logic Stack
The following is true of Sequence Control Relay instructions:
 All logic between the LSCR and the SCRE instructions make up the SCR
segment and are dependent upon the value of the S stack for its execution.
Logic between the SCRE and the next LSCR instruction have no dependency
upon the value of the S stack.
 The SCRT instruction sets an S bit to enable the next SCR and also resets the
S bit that was loaded to enable this section of the SCR segment.
Restrictions
Restrictions for using SCRs follow:
 You cannot use the same S bit in more than one routine. For example, if you
use S0.1 in the main program, do not use it in the subroutine.
 You cannot use the JMP and LBL instructions in an SCR segment. This means
that jumps into, within, or out of an SCR segment are not allowed. You can use
jump and label instructions to jump around SCR segments.
 You cannot use the FOR, NEXT, and END instructions in an SCR segment.