162
Using Tasks Section 4-2
Relationship of Tasks to
Condition Flags
All Condition Flags will be cleared before execution of each task. Therefore
Condition Flag status at the end of task 1 cannot be read in task 2. With a
CS1-H, CJ1-H, or CJ1M CPU Unit, however, CCS(282) and CCL(283) can be
used to read Condition Flag status from another part of the program, e.g.,
from another task.
Note When the status of Condition Flags is monitored from a Programming Con-
sole, the Programming Console will show the flags’ status at the end of the
cycle, i.e., their status at the end of the last task in the cycle.
4-2-2 Task Instruction Limitations
Instructions Required in the Same Task
The following instructions must be placed within the same task. Any attempt
to split instructions between two tasks will cause the ER Flag to turn ON and
the instructions will not be executed.
Instructions Not Allowed in Interrupt Tasks
The following instructions cannot be placed in interrupt tasks. Any attempt to
execute one of these instructions in an interrupt task will cause the ER Flag to
turn ON and the instruction will not be executed.The following instructions can
be used if an interrupt task is being used as an extra task.
The operation of the following instructions is unpredictable in an interrupt task:
TIMER: TIM and TIMX((550), HIGH-SPEED TIMER: TIMH(015) and
TIMHX(551), ONE-MS TIMER: TMHH(540) and TMHHX(552), ACCUMULA-
TIVE TIMER: TTIM(087) and TTIMX(555), MULTIPLE OUTPUT TIMER:
MTIM(543) and MTIMX(554), LONG TIMER: TIML(542) and TIMLX(553),
TIMER WAIT: TIMW(813) and TIMWX(816), HIGH-SPEED TIMER WAIT:
TMHW(815) and TMHWX(817), PID CONTROL: PID(190), FAILURE POINT
DETECTION: FPD(269), and CHANGE SERIAL PORT SETUP: STUP(237).
The following instructions cannot be used in the power OFF interrupt task
(they will not be executed even if they are used and the Error Flag will not turn
ON):
READ DATA FILE: FREAD(700), WRITE DATA FILE: FWRIT(701), NET-
Mnemonic Instruction
JMP/JME JUMP/JUMP END
CJP/JME CONDITIONAL JUMP/JUMP END
CJPN/JME CONDITIONAL JUMP NOT/CONDITIONAL JUMP END
JMP0/JME0 MULTIPLE JUMP/JUMP END
FOR/NEXT FOR/NEXT
IL/ILC INTERLOCK/INTERLOCK CLEAR
SBS/SBN/RET SUBROUTINE CALL/SUBROUTINE ENTRY/SUBROUTINE
RETURN
MCRO/SBN/RET MACRO/SUBROUTINE ENTRY/SUBROUTINE RETURN
BPRG/BEND BLOCK PROGRAM BEGIN/BLOCK PROGRAM END
STEP S/STEP STEP DEFINE
Mnemonic Instruction
TKON(820) TASK ON
TKOF(821) TASK OFF
STEP STEP DEFINE
SNXT STEP NEXT
STUP CHANGE SERIAL PORT SETUP
DI DISABLE INTERRUPT
EI ENABLE INTERRUPT
To Next Page
Loading...
Need help?
General
