Omron CPM1 - PROGRAMING MANUAL 02-2001 Programming Manual page 72

CPM2A/CPM2C High-speed Counters
Phase Z
Selecting the Interrupts to be Used
High-speed Counter
Interrupts
Count Values
The range of numbers counted by the high-speed counter are in linear mode
only. If the count is outside of the permissible range, an overflow or underflow will
result. The PV will become 0FFFFFFF if an overflow occurs, or FFFFFFFF if an
underflow occurs, and the comparison will be stopped.
Differential phase input
mode
Pulse + direction input
mode
Up/down pulse input
mode
Increment mode
To restart the count following an overflow or underflow, reset the PV. (The PV is
automatically reset whenever operation is started or stopped.)
Reset Method
Either of the following two methods can be selected for resetting the counter PV
to 0.
Phase-Z Signal (Reset Input) + Software Reset
The PV is reset when a phase-Z signal (i.e., a reset input) turns ON while the
High-speed Counter Reset Flag (25200) is ON.
1 scan
Reset Reset
Software Reset
The PV is reset when the High-speed Counter Reset Flag (25200) turns ON.
The High-speed Counter Reset Flag (25200) is refreshed with every scan, so it
must remain ON for at least one cycle time to be certain it is read.
Even when the PV is reset, the comparison table registration status, the compar-
ison execution status, and the range comparison results are all retained just as
they were before the PV reset. (If a comparison was underway prior to the PV
reset, that comparison will be continued with no change following the reset.)
Following the reset, the High-speed Counter Reset Flag (25200) must be turned
OFF in order to be able to execute the next reset. To be certain that it is turned
OFF, it must be remain OFF for at least one cycle time.
High-speed counter interrupts use a comparison table and perform a count
check by either of the methods described below (i.e., target value comparison or
range comparison). If the conditions are satisfied, then an interrupt is generated.
Underflow (FFFFFFFF)
Not reset Reset
1 scan
Reset Not reset Not reset
Section
Overflow (0FFFFFFF)
Overflow (0FFFFFFF)
Not reset
Not reset
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