2-17
2 Instructions
CP1E CPU Unit Instructions Reference Manual(W483)
Sequence Input Instructions
2
UP/DOWN
UP/DOWN
Applicable Program Areas
Flags
There are no flags affected by UP(521) and DOWN(522).
Function
Precautions
The operation of UP(521) and DOWN(522) depends on the execution condition for the instruction as
well as the execution condition for the program section when it is programmed in an interlocked pro-
gram section, a jumped program section, or a subroutine.
The operation of UP(521) and DOWN(522) will not be consistent if the same subroutine is executed
more than once in the same cycle.
An subroutine will not be executed while the input condition for the subroutine is OFF. Caution is thus
required when using UP(521) and DOWN(522) in a function block definition. For details, refer to infor-
mation on SBS(091).
Sample program

UP

i
Instruction Mnemonic Variations Function
code Function
CONDITION ON UP --- 521
UP(521) turns ON the execution condition for the
next instruction for one cycle when the execution
condition it receives goes from OFF to ON.
CONDITION OFF DOWN --- 522
DOWN(522) turns ON the execution condition for
the next instruction for one cycle when the execu-
tion condition it receives goes from ON to OFF.
Symbol
UP DOWN
Area Step program areas Subroutines Interrupt tasks
Usage OK OK OK

UP

UP(521) is placed between an execution condition and another instruction to turn the execution condi-
tion into an up-differentiated condition. UP(521) causes the connecting instruction to be executed just
once when the execution condition goes from OFF to ON.

DOWN

DOWN(522) is placed between an execution condition and another instruction to turn the execution
condition into a down-differentiated condition. DOWN(522) causes the connecting instruction to be exe-
cuted just once when the execution condition goes from ON to OFF.
UP(521) DOWN(522)
UP
0.00 100.01
0.00
100.01
Cycle
time
When CIO 0.00 goes from OFF to ON, CIO
100.01 is turned ON for just one cycle.