Omron SYSMAC C200HS Operation Manual page 144

Bit Control Instructions
Description
00002 00003
00500
00002
00003
Flags
Precautions
134
KEEP(11) is used to maintain the status of the designated bit based on two exe-
cution 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, regard-
less of whether S stays ON or goes OFF. When R turns ON, the designated 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.
S execution condition
R execution condition
Status of B
KEEP(11) operates like the self-maintaining bit described in 4-8-3 Self-maintain-
ing Bits. 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.
Exercise caution when using a KEEP reset line that is controlled by an external
normally closed device. Never use an input bit in an inverse condition on the re-
set (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 situ-
ation is shown below.
Input Unit
A
NEVER
Bits used in KEEP are not reset in interlocks. Refer to the 5-10 INTERLOCK –
and INTERLOCK CLEAR IL(02) and ILC(03) for details.
Address Instruction
00500
00000 LD
00001 OR
00002 AND NOT
00003 OUT
Address Instruction
00000 LD
KEEP(11)
00001 LD
B
00002 KEEP(11)
A
Section 5-9
Operands
00002
00500
00003
00500
Operands
00002
00003
00500
S
KEEP(11)
B
R