Omron CJ1G-CPU series, Programming Manual

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Startup Settings and Maintenance Section 6-6
6-6-3 RUN Output
Some of the Power Supply Units (the C200HW-PA204R, C200HW-PA209R,
and CJ1W-PA205R) are equipped with a RUN output. This output point is ON
(closed) when the CPU Unit is operating in RUN or MONITOR mode and OFF
(open) when the CPU Unit is in PROGRAM mode.
This RUN output can be used to create an external safety circuits, such as an
emergency stop circuit that prevents an Output Unit’s external power supply
from providing power unless the PLC is on.
Note When a Power Supply Unit without a RUN output is used, an equivalent out-
put can be created by programming the Always ON Flag (A1) as the execu-
tion condition for an output point from an Output Unit.
!Caution
If Output Unit’s external power supply goes on before the PLC’s power supply,
the Output Unit may malfunction momentarily when the PLC first goes on. To
prevent any malfunction, add an external circuit that prevents the Output
Unit’s external power supply from going on before the power supply to the
PLC itself. Create a fail-safe circuit like the one described above to ensure
that power is supplied by an external power supply only when the PLC is
operating in RUN or MONITOR mode.
6-6-4 Power OFF Detection Delay Setting
Normally a power interruption will be detected about 10 to 25 ms (2 to 5 ms
for DC power supplies) after the power supply voltage drops below 85% of the
minimum rated value(80% for DC power supplies). There is a setting in the
PLC Setup (address 225 bits 0 to 7, Power OFF Detection Delay Time) that
can extend this time by up to 10 ms (up to 2 ms for DC power supplies).
When the power OFF interrupt task is enabled, it will be executed when the
power interruption is confirmed, otherwise the CPU will be reset and operation
will be stopped.
Related Settings
6-6-5 Disabling Power OFF Interrupts
This function is supported only by the CS1-H, CJ1-H, or CJ1M CPU Units.
With CS1-H, CJ1-H, or CJ1M CPU Units, areas of the program can be pro-
tected from power OFF interrupts so that they will be executed before the
CPU Unit even if the power supply is interrupted. This is achieved by using
the DISABLE
INTERRUPTS (DI(693)) and ENABLE INTERRUPTS (EI(694)) instructions.
Power Supply Unit
RUN output
Address Name Meaning Setting Default
CIO 256,
bits 00 to
07 Power
OFF
Detection
Delay Set the time to
delay before
detecting a
power interrup-
tion. 00 to 0A (Hex): 0 to 10 ms 00 (Hex):
0 ms