Instruction Execution For Power Interruptions - Omron SYSMAC CS Series Operation Manual

Power OFF Operation

10-3-2 Instruction Execution for Power Interruptions

Disabling Power Interruption Processing in the Program
1,2,3...
If power is interrupted and the interruption is confirmed when the CPU Unit is
operating in RUN or MONITOR mode, the instruction currently being executed
will be completed (see note) and the following power interruption processing
will be performed.
• If the power OFF interrupt task has not been enabled, the CPU Unit will
be reset immediately.
• If the power OFF interrupt task has been enabled, the task will be exe-
cuted and then the CPU Unit will be reset immediately.
The power OFF interrupt task is enable and disabled in the PLC Setup.
Note The current instruction can be completed only when the time required to com-
plete execution is less than or equal to the processing time after power inter-
ruption detection (10 ms − power interruption detection delay time). If the
instruction is not completed within this time, it will be interrupted and the
above processing will be performed.
With CS1-H CPU Units, if the power OFF interrupt task is disabled, areas of
the program can be protected from power interruptions so that the instructions
will be executed before the CPU Unit performs power OFF processing even if
the power supply is interrupted. This is achieved by using the DISABLE
INTERRUPTS (DI(693)) and ENABLE INTERRUPTS (EI(694)) instructions.
The following procedure is used.
1. Insert DI(693) before the program section to be protected to disable inter-
rupts and then place EI(694) after the section to enable interrupts.
W0.00
2. Set the Disable Setting for Power OFF Interrupts in A530 to A5A5 hex to
enable disabling power interruption processing.
Note A530 is normally cleared when power is turned OFF. To prevent this,
the IOM Hold Bit (A50012) must be turned ON and the PLC Setup
must be set to maintain the setting of the IOM Hold Bit at Startup, or
the following type of instruction must be included at the beginning of
the program to set A530 to A5A5 hex.
A20011
First Cycle Flag
3. Disable the Power OFF Interrupt Task in the PLC Setup.
Interrupt tasks disabled.
DI
Instructions that cannot be
interrupted when a power
interruption occurs
Interrupt tasks enabled.
EI
Set A530 to A5A5 hex at the
MOV
beginning of the program to enable
#A5A5
disabling power interruption
A530
processing.
Section 10-3
Power interruption
confirmed.
Instructions executed here.
493