5 special functions using high-speedcounters, 1 specified frequency pulse output function, 5 special functions using high-speed counters – KEYENCE Visual KV Series User Manual
Page 252: Visual kv series
4.5 Special Functions Using High-speed Counters
3-228
Visual KV
Series
4
Chapter 4 High-speed Counters
OFF
ON
4.5
Special Functions Using High-speed
Counters
This section describes the specified frequency pulse output function, frequency
counter function, and cam switch function.
4.5.1
Specified Frequency Pulse Output Function
With high-speed counter CTH1, output pulses from output relay 0501 with the
frequency (Hz) specified in data memory DM1936. To activate this function, write the
desired value into DM1936 and turn ON special utility relay 2306.
The internal clock of the high-speed counter is automatically set to 1 µs. Pulses with
duty ratio of 1:1 are output at the preset frequency obtained with the calculation
"1,000,000/2/Output frequency".
The KV performs the following operations after each scan time during the specified
frequency pulse output function.
•
Stops pulse output when special utility relay 2306 is turned OFF.
•
Sets the preset value so that pulses are output at the frequency specified with
the DM. (Pulse duty ratio: fixed to 50%)
•
Starts pulse output.
Pulse duty
Pulse duty is the ratio of the pulse widths between ON time and OFF time. A pulse
duty of 50% means that the pulse widths between ON time and OFF time are the
same, as follows.
The ratio between ON and OFF time is 1:1.
■ Device used for specified frequency pulse output
Special utility relays
Data memory
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Visual KV Series Only
KVNKA Chap 04_2.p65
08.3.11, 0:08 PM
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