Omron CP - PROGRAMMING MANUAL 05-2007 Programming Manual page 788

Step Instructions
Note
Flags:STEP(008)
Flags:SNXT(009)
Precautions
Instruction output
The following timer instruc-
tions: TIM, TIMX(551),
TIMH(015), TIMHX(551),
TMHH(540), TIMHHX(552),
TIML(542), and TIMLX(553)
Bits or words specified for other instructions (see note)
Indicates all other instructions, such as TTIM(087), TTIMX(555), MTIM(543),
MTIMX(554), SET, REST, CNT, CNTX(546), CNTR(012), CNTRX(548),
SFT(010), and KEEP(011).
The STEP(008) instruction must be placed at the beginning of each step.
STEP(008) is placed at the beginning of a step area to define the start of the
step.
Ending the Step Programming Area
STEP(008) is placed at the end of the step programming area without an
operand to define the end of step programming When the control bit preced-
ing a SNXT(009) instruction is turned OFF, step execute is stopped by
SNXT(009).
Name Label
Error Flag ER
Name Label
Error Flag ER
The control bit, B, must be in the Work Area for STEP(008)/SNXT(009).
A control bit for STEP(008)/SNXT(009) cannot be use anywhere else in the
ladder diagram. If the same bit is used twice, as duplication bit error will occur.
If SBS(091) is used to call a subroutine from within a step, the subroutine out-
puts and instructions will not be interlocked when the control bit turns OFF.
Control bits within one section of step programming must be sequential and
from the same word.
SNXT(009) will be executed only once, i.e., on the rising edge of the execution
condition.
Input SNXT(009) at the end of the step programming area and make sure that
the control bit is a dummy bit in the Work Area. If a control bit for a step is
used in the last SNXT(009) in the step programming area, the corresponding
step will be started when SNXT(009) is executed.
An error will occur and the Error Flag will turn ON if the operand B specified
for SNXT(009) or STEP(008) is not in the Work Area or if the step program
has been placed anywhere but in a cyclic task.
A200.12 (Step Flag) is turned ON for one cycle when STEP(008) is executed.
This flag can be used to conduct initialization once the step execution has
started.
PV
Completion Flag
Operation
ON when the specified bit B is not in the WR area.
ON when STEP(008) is used in an interrupt program.
OFF in all other cases.
Operation
ON when the specified bit B is not in the WR area.
ON when SNXT(009) is used in an interrupt program.
OFF in all other cases.
Section 3-21
Status
0000 hex (reset)
OFF (reset)
Holds the previous status
(but the instructions are
not executed)
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