Differentiate Up And Down - Difu(13) And Difd(14; Differentiate Up And Down - Difu(13) And Difd(14) - Omron SYSMAC C20P Operation Manual

Bit Control Instructions
Flags
5–6–2 Differentiate Up and Down – DIFU(13) and DIFD(14)
Limitations
Description
50
OUT turns ON the designated bit for a ON execution condition, and turns
OFF the designated bit for an OFF execution condition. OUT with a TR bit
appears at a branching point rather than at the end of an instruction line. Re-
fer to 4–3–4 Branching Instruction Lines for details.
OUT NOT turns ON the designated bit for a OFF execution condition, and
turns OFF the designated bit for an ON execution condition.
OUT and OUT NOT can be used to control execution by turning ON and OFF
bits that are assigned to conditions on the ladder diagram, thus determining
execution conditions for other instructions. This is particularly helpful when a
complex set of conditions can be used to control the status of a single work
bit, and then that work bit can be used to control other instructions.
The length of time that a bit is ON or OFF can be controlled by combining the
OUT or OUT NOT with TIM. Refer to Examples under 5–11–1 Timer – TIM
for details.
There are no flags affected by these instructions.
Ladder Symbol
DIFU(13)
Ladder Symbol
DIFD(14)
Any output bit can be used in only one instruction that controls its status. See
3–3–1 I/O Words for details.
DIFU(13) and DIFD(14) are used to turn the designated bit ON for one scan
only.
Whenever executed, DIFU(13) compares its current execution with the previ-
ous execution condition. If the previous execution condition was OFF and
and current one is ON, DIFU(13) will turn ON the designated bit. If the previ-
ous execution condition was ON and the current execution condition is either
ON or OFF, DIFU(13) will turn the designated bit OFF or do nothing (i.e., if
the designated bit is already OFF). The designated bit will thus never be ON
for longer than one scan assuming it is executed each scan (see Precau-
tions, below).
Whenever executed, DIFD(14) compares its current execution with the previ-
ous execution condition. If the previous execution condition was ON and the
current one is OFF, DIFD(14) will turn ON the designated bit. If the previous
execution condition was OFF and the current execution condition is either
ON or OFF, DIFD(14) will turn the designated bit OFF or do nothing (i.e., if
the designated bit is already OFF). The designated bit will thus never be ON
for longer than one scan.
These instructions are used when a single-scan execution of a particular in-
struction is desired. Examples of these are shown below.
Operand Data Areas
B
Operand Data Areas
B
Section 5–6
B: Bit
IR, HR
B: Bit
IR, HR