Using The Stage Jump Instruction For State Transitions; Stage Jump, Set, And Reset Instructions - Automation Direct DL05 User Manual

Using the Stage Jump Instruction for State Transitions

Stage Jump, Set, and Reset Instructions

The Stage JMP instruction we have used deactivates the stage in which the instruction occurs,
while activating the stage in the JMP instruction. Refer to the state transition shown below.
When contact X0 energizes, the state transition from S0 to S1 occurs. The two stage examples
shown below are equivalent. So, the Stage Jump instruction is equal to a Stage Reset of the
current stage, plus a Stage Set instruction for the stage to which we want to transition.
SG
Please Read Carefully – The jump instruction is easily misunderstood. The "jump" does not
occur immediately like a GOTO or GOSUB program control instruction when executed.
Here's how it works:
• The jump instruction resets the stage bit of the stage in which it occurs. All rungs in the stage still
finish executing during the current scan, even if there are other rungs in the stage below the jump
instruction!
• The reset will be in effect on the following scan, so the stage that executed the jump instruction
previously will be inactive and bypassed.
• The stage bit of the stage named in the Jump instruction will be set immediately, so the stage will be
executed on its next occurrence. In the left program shown below, stage S1 executes during the same
scan as the JMP S1 occurs in S0. In the example on the right, Stage S1 executes on the next scan
after the JMP S1 executes, because stage S1 is located above stage S0.
NOTE: Assume we start with Stage 0 active and stage 1 inactive for both examples.
S0
S0
S1
X0
JMP
SG
S0
X0 S1
JMP
Executes on same
SG
S1 scan as Jmp
Y0
S1
OUT
DL05 Micro PLC User Manual, 6th Edition, Rev. A
Chapter 7: RLL
X0
S1
SG
S0
Equivalent
X0
Executes on next
SG
S1 scan after Jmp
S1
SG
S0
X0
Stage Programming
PLUS
S0
RST
S1
SET
Y0
OUT
S1
JMP
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