Differentiate Up/Down: Difu(013) And Difd - Omron SYSMAC CVM1 Series Operation Manual

Bit Control Instructions

5-7-2 DIFFERENTIATE UP/DOWN: DIFU(013) and DIFD(014)

DIFFERENTIATE UP: DIFU(013)
Ladder Symbol
Variations
!DIFU(013)
DIFFERENTIATE DOWN: DIFD(014)
Ladder Symbol
Variations
!DIFD(014)
Description
Precautions
Flags
(013)
DIFU B
(014)
DIFD B
DIFU(013) and DIFD(014) are used to turn the designated bit ON for one cycle
only.
Whenever executed, DIFU(013) compares its current execution with the pre-
vious execution condition. If the previous execution condition was OFF and the
current one is ON, DIFU(013) will turn ON the designated bit. If the previous
execution condition was ON and the current execution condition is either ON or
OFF, DIFU(013) will either turn the designated bit OFF or leave it OFF (i.e., if the
designated bit is already OFF). The designated bit will thus never be ON for long-
er than one cycle, assuming it is executed each cycle (see Precautions, below).
Whenever executed, DIFD(014) compares its current execution with the pre-
vious execution condition. If the previous execution condition is ON and the cur-
rent one is OFF, DIFD(014) will turn ON the designated bit. If the previous execu-
tion condition was OFF and the current execution condition is either ON or OFF,
DIFD(014) will either turn the designated bit OFF or leave it OFF. The desig-
nated bit will thus never be ON for longer than one cycle, assuming it is executed
each cycle (see Precautions, below).
These instructions are used when differentiated instructions (i.e., those prefixed
with a j or i,) are not available and single-cycle execution of a particular instruc-
tion is desired. They can also be used with non-differentiated forms of instruc-
tions that have differentiated forms when their use will simplify programming.
Examples of these are shown below.
Note: Immediate-refresh variations can be used in simplex mode only; they cannot be
used in duplex mode.
Any output bit is generally used in only one instruction that controls its status.
DIFU(013) and DIFD(014), operation can be uncertain when the instructions are
programmed between IL and ILC, between JMP and JME, or in subroutines. Re-
fer to 5-8 INTERLOCK and INTERLOCK CLEAR: IL(002) and ILC(003), 5-9
JUMP and JUMP END: JMP(004) and JME(005), and 5-30 Subroutines for de-
tails.
Note: Refer to page 101 for general precautions on operand data areas.
There are no flags affected by these instructions.
Operand Data Area
B: Bit CIO, G, A
Operand Data Area
B: Bit CIO, G, A
Section 5-7
113