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5-19 Special Instructions
The following instructions provide for special purposes: refreshing I/O bits
during program execution, designating minimum cycle time, and inserting
comments into a program.
5-19-1 I/O REFRESH – IORF(97)
St : Starting word
IR (00 through 09)
Ladder Symbol
E : End word
IR (00 through 09)
Operand Data Areas
IORF(97)
St
E
IORF can be used for refreshing I/O words allocated on the CPU or an Ex-
pansion I/O Rack only. It cannot be used for other I/O words. St must be less
than or equal to E.
When the execution condition is OFF, IORF(97) is not executed and the next
instruction is moved to. When the execution condition is ON, all words be-
tween St and E will be refreshed. This will be in addition to the normal I/O
refresh performed during the PC’s cycle.
The execution time for IORF(97), T
IORF
, is computed as follows:
T
IORF
= 40 µs + (74 µs x number of words refreshed)
There are no flags affected by this instruction.
5-19-2 END WAIT – ENDW(62)
Ml : Multiplier (BCD)
#
Ladder Symbol Operand Data Areas
ENDW(62)
Ml
ENDW(62) can be used to specify a minimum cycle time for the PC. When
the execution condition is OFF, ENDW(62) is not executed and the next in-
struction is moved to. When the execution condition is ON, the CPU will wait
at the end of program execution until the cycle time reaches 100 µs X Ml be-
ginning the next cycle. If program execution requires less that the minimum
time set, a wait will be inserted immediately after execution of END(01).
If the minimum cycle time set with ENDW(62) is exceeded by normal pro-
gram execution, the cycle will continue as normal. If more than one
ENDW(62) is written into the program, only the last one will be effective.
The accuracy of TIMH(15) may be affected if Ml is greater than 10. The accu-
racy of TIM and the response speed of the Programming Console may be
affected if Ml is set to greater than 1,000.
The cycle time set with ENDW(62) is accurate to plus or minus 0.05 ms.
There are no flags affected by this instruction.
Limitations
Description
Execution Time
Flags
Description
Flags
Special Instructions Section 5-19