Keep - Keep(11) - Omron SYSMAC C2000H Operation Manual

Bit Control Instructions
5-7-3 KEEP – KEEP(11)
Ladder Symbol
Limitations
Description
S execution condition
R execution condition
Status of B
00002 00003
00500
00002
00003
Flags
Precautions
112
S
KEEP(11)
B
R
Any output bit can generally be used in only one instruction that controls its
status. Refer to 3-2 IR Area for details and to 5-20 Block Instructions for in-
formation on using output bits in SET<07> and RSET<08>.
KEEP(11) is used to maintain the status of the designated bit based on two
execution conditions. These execution conditions are labeled S and R. S is
the set input; R, the reset input. KEEP(11) operates like a latching relay that
is set by S and reset by R.
When S turns ON, the designated bit will go ON and stay ON until reset, re-
gardless of whether S stays ON or goes OFF. When R turns ON, the desig-
nated bit will go OFF and stay OFF until reset, regardless of whether R stays
ON or goes OFF. The relationship between execution conditions and
KEEP(11) bit status is shown below.
KEEP(11) operates like the self-maintaining bit described in 4-7-3 Self-main-
taining Bits (Seal). The following two diagrams would function identically,
though the one using KEEP(11) requires one less instruction to program and
would maintain status even in an interlocked program section.
S
R
There are no flags affected by this instruction.
Never use an input bit in a normally closed condition on the reset (R) for
KEEP(11) when the input device uses an AC power supply. The delay in
shutting down the PC's DC power supply (relative to the AC power supply to
the input device) can cause the designated bit of KEEP(11) to be reset. This
situation is shown below.
Operand Data Areas
B: Bit
IR, AR, HR, LR
Address Instruction
00500
00000 LD
00001 OR
00002 AND NOT
00003 OUT
Address Instruction
00000 LD
KEEP(11)
00001 LD
00500
00002 KEEP(11)
Section 5-7
Operands
00002
00500
00003
00500
Operands
00002
00003
00500