4 special functions, 1 input time constant change function – KEYENCE Visual KV Series User Manual
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1.4 Special Functions
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Chapter 1 Programming
1.4
Special Functions
This section describes special functions to set and confirm operations on the Visual
KV Series, and useful functions for program debugging and adjustment of external
equipment.
1.4.1
Input Time Constant Change Function
The input time constant can be changed when a signal is read from an input contact.
When connecting external equipment which has no contact in which chattering such
as transistor outputs does not occur, and inputting pulses of short width, the input
time constant change function can be used to decrease the input time constant.
Setting the input time constant for basic units using special utility relays
The input time constant for a basic unit can be changed using data memory DM1940
and special utility relay 2813.
Though the input time constant is usually 10 ms, it can be changed to a value that
corresponds to the number stored in DM1940 by setting special utility relay 2813 to
ON.
If the HSP instruction and special utility relay 2813 are used at the same time,
priority is given to the HSP instruction and the number stored in DM1940 is ignored.
■ Special utility relay 2813
OFF: Sets the input time constant to 10 ms.
ON:
Refers to the number stored in DM1940, then determines the input time
constant.
Note 1: Be sure to set the input time constant to 10 µs when using the 30-kHz high-speed
counter input.
Note 2: Never enter a number that is 7 or larger to data memory DM1940.
Note 3: The input time constant specified by data memory DM1940 becomes effective at the
rising edge of special utility relay 2813.
To change the input time constant, first change data memory DM1940, then set special utility
relay to OFF and ON again. Or change the operation mode of the KV basic unit from
PROGRAM to RUN.
Note 4: The input time constant for input relays set by the HSP instruction is 10 µs.
➮ For more about the HSP instruction, refer to "HSP instruction" (p.3-86).
➮ For more about setting the input time constant for expansion units, refer to "Input time
constant for expansion units" (p.1-76).
Note 5: Set the special utility relay using the SET/RES instructions.
Note 6: When the input time constant is set to 1 ms or less, connect the output equipment
without contacts. If connecting output equipment with contacts, contact bounds may enter.
Note 7: Except for interrupts and high-speed counters, signals whose ON time is shorter than
the scan time may not be received even if the input time constant is set to a small value.
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KVNKA Chap 01P.p65
08.3.11, 11:49 AM
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