Disabling Power Off Interrupts - Omron CJ2 CPU UNIT SOFTWARE User Manual

10-3-3 Disabling Power OFF Interrupts

Areas of the program can be protected from power OFF interrupts so that they will be executed before
the CPU Unit is reset even if the power supply is interrupted. This is achieved by using the DISABLE
INTERRUPTS (DI(693)) and ENABLE INTERRUPTS (EI(694)) instructions.
This function can be used with sets of instructions that must be executed as a group, e.g., so that exe-
cution does not start with intermediate stored data the next time power is turned ON.
Procedure
1
Set the Disable Setting for Power OFF Interrupts in A530 to A5A5 hex to enable disabling Power
OFF Interrupts.
2
Enable disabling Power OFF Interrupts in the PLC Setup (this is the default setting).
3
Use DI(693) to disable interrupts before the program section to be protected and then use
EI(694) to enable interrupts after the section. All instructions between DI(693) and EI(694) will be
completed before the Power OFF Interrupt is executed even if the power interruption occurs
while executing the instructions between DI(693) and EI(694).
Execution condition
Power supply drops below
85% of rated value (80%
for DC power supplies).
Auxiliary Area Flags and Words
Name
Disable Setting for Power OFF
Interrupts
CJ2 CPU Unit Software User's Manual
CPU Unit
Power interruption
reset (forced
detected.
end)
Instructions executed
D
through EI(694).
I
Power OFF
10 ms - Power OFF
detection time +
detection delay
Power OFF
(Power OFF
detection delay
confirmation time)
Address
A530
Interrupts disabled.
DI
Power interrupted.
Instructions executed.
Interrupts enabled, causing
EI
CPU Unit to be reset.
Stop
E
I
Enables using DI(693) to disable power OFF interrupt
processing (except for execution of the Power OFF Inter-
rupt Task) until EI(694) is executed.
A5A5 hex: Enables using DI(693) to disable power OFF
interrupt processing
Any other value: Disables using DI(693) to disable power
OFF interrupt processing
10 CPU Unit Functions
Meaning
10-25
10