Omron CJ1M-CPU21, Operation Manual

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Built-in Inputs Section 6-1
Restrictions
• There are no negative values in ring mode.
• If the max. ring count is set to 0 in the PLC Setup, the counter will operate
with a max. ring count of FFFFFFFF hex.
Reset Methods
Phase-Z Software
Reset The high-speed counter's PV is reset when the phase-Z signal (reset input)
goes from OFF to ON while the corresponding High-speed Counter Reset Bit
(A53100 or A53101) is ON.
The CPU Unit recognizes the ON status of the High-speed Counter Reset Bit
only at the beginning of the PLC cycle during the overseeing processes. Con-
sequently, when the Reset Bit is turned ON in the ladder program, the phase-
Z signal (bit 02 or 03 of CIO 2960) does not become effective until the next
PLC cycle.
Software Reset The high-speed counter's PV is reset when the corresponding High-speed
Counter Reset Bit (A53100 or A53101) goes from OFF to ON.
The CPU Unit recognizes the OFF-to-ON transition of the High-speed
Counter Reset Bit only at the beginning of the PLC cycle during the oversee-
ing processes. Reset processing is performed at the same time. The OFF-to-
ON transition will not be recognized if the Reset Bit goes OFF again within the
same cycle.
Note With CJ1M CPU Unit Ver. 2.0, the comparison operation can be set to stop or
continue when a high-speed counter is reset. This enables applications where
the comparison operation can be restarted from a counter PV of 0 when the
counter is reset.
Starting Interrupt Tasks at Desired Counter PVs
Data registered in advance in a comparison table can be compared with the
actual counter PVs during operation. The specified interrupt tasks (registered
in the table) will be started when the corresponding comparison condition is
met.
There are two comparison methods available: Target value comparison and
range comparison.
• Use the CTBL(882) instruction to register the comparison table.
One cycle
Phase-Z
Reset Bit
PV not
reset
PV not
reset
PV
reset PV
reset
PV
reset PV
reset
One cycle
Reset Bit
PV not
reset PV
reset PV not
reset PV not
reset