3 Operation and Configuration
3-34
CJ-series High-speed Counter Units Operation Manual for NJ-series CPU Unit(W492)
Additional Information
Precautions When Setting Comparison Data
• Comparison Stoppage When Comparison Value Reached
When the High-speed Counter Value reaches a comparison value, comparison stops for 1.5
ms. The other Counters, however, do not stop comparisons.
Set the Comparison Data considering the time when the comparison is stopped.
For example, for the Comparison table shown in the following diagram, approximately 4.8
counts occur during 1.5 ms when a 3.2 kHz pulse is input. This means that comparison does
not occur for Counter Values 101, 102, 103, and 104. During this period, the Output set under
the Output Pattern does not turn ON.
Comparison starts again after this 1.5 ms has elapsed.
At this time, the processing returns to the stoppage period and Comparison Data 1 and 2 are
executed at the same time.
Additional Information
• Multiple Comparison Values of a specific Counter may not have the same value. The Unit will
generate an error if multiple CV's have the same value (refer to 5-2 Error codes for more
details).
• The Digital Outputs are Set/Reset in the chronological order of reaching the CV's. After reach-
ing a (new) CV the (old) Unit Output Pattern is updated.
• In case for a CV both a Set and a Reset in one and the same counting direction for a specific
Output are defined, the Reset has priority.
• The output can be set to Set, Reset, or No Change when a CV is reached both for increment-
ing and decrementing. Each time, the output pattern for both Counters will change in the order
CVs are reached.
• Do not change the counting direction quickly near a CV. If the direction is changed near a CV,
the direction in which the CV was reached (incrementing or decrementing) may be incorrectly
detected.
100
101
102
103
104
105
3.2-kHz
pulse
Counter Value
Comparison
Data 1
Comparison
Data 2
Comparison
Data 0
Counter Value
matches
comparison value
Comparison is stopped for 1.5 ms.
Outputs set under the Output Pattern will not turn ON
during this period even if the Counter Value equals the
comparison value