VOL.Example

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High-speed interrupt input function22

Measure the time during which the target passes two points A and B and calculate the passing speed.The FS-M1H high-speed response photoelectric sensor is used as the sensor. The passing time is measured withthe internal clock of the high-speed counter in the unit of s.

Applications: Measurement of the swing speed of a golf club head.

Programming TechniquePoint 1: Measure the passing time with the internal clock of the KV. Use the KVs internal clock (1-s cycle) and the high-speed counter to measure the passing time.

(Passing time) = (Cycle of internal clock: 1 s) x (No. of clock counts)

Point 2 The interrupt (INT) instruction is the best for the program. When the sensor detects the target, the interrupt is executed. Store the current value of the high-speed counter

in the data memory.When the interrupt is executed, the current value of the high-speed counter is automatically stored in the datamemory (Input capture function).By using this function, the passing time is obtained as the difference between the stored counter values ofsensor 1 and sensor 2.

(Passing time) = [yyyyy (DM1934) - xxxxx (DM1932)] x (Cycle of internal clock: 1 s)

ONOFF

ONOFF

Sensor 2INPUT 0003

Sensor 1INPUT 0002

Sensor 1

Sensor 2

Sensor 1

Sensor 2

Internal clock(1 s) No. of clock

counts

Passingtime

DM1934DM1932

No. of clockcounts

Sensor 1(Interrupt 0002)

Passingtime

Sensor 2(Interrupt 0003)

Internal clock(1 s)

No. of pulses = xxxxx No. of pulses = yyyyy

(Value stored by the input capture of 0003)(Value stored by the input capture of 0002)

Measurement of passing time between two points using high-speed interrupt input

Outline

Visual KV Series

Passing time (s)

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VOL. 22 High-speed interrupt input function

Programming Example Measures the time from when input relay 0002 turns ON until input relay 0003 turn ON. The measured value is written to data memory DM0000 (Unit: s). Writes the calculated speed into DM0010 (unit: m/ms).

(This program sets the distance between sensor 1 and sensor 2 to 1 m.)2008

2002

2002

2412RES

2413RES

2410RES

2411RES

HSP0002

CTH12200

END

0002

RETI

RETI

ENDH

HSP0003

2002 DM0000STA

DM1932SUB

DM1934LDA

DM0010STA

DM0000DIV

#01000MUL

#00001LDA(1) (2)

EI

INT

0003INT

#00100MUL

#00100LDA

DM0000DIV

DM0010STA

#01000MUL

When power is turned on, an EL instruction enablesinterrupts. Sets the interrupt polarity of inputs 0002 and0003 to the rising edge.

Sets the input time constant of inputs 0002 and 0003 to10 s.

CTH1 counts the pulses using a 1-s internal clock.

When INT0002 is executed, the current value of CTH1 isautomatically transferred to DM1932 and DM1933 (Inputcapture).

When INT0003 is executed, the current value of CTH1 isautomatically transferred to DM1934 and DM1935 (Inputcapture).Subtracts the input capture value of INT0002 from thatof INT0003 to obtain the time it takes for the target topass between two points and then writes it to DM0000.(Unit: 1s)The passing speed is obtained through calculating (2)the passing time and (1) the distance between the twopoints (unit: m/ms). It is stored in DM0010.

Calculation of passing speedThe passing speed is calculated with the following expression:

Passing speed (m/ms) = ((1) Distance between two points [Unit: m]) / ((2) Passing time [Unit: ms])

In the program above, the passing time is measured in the unit of s. Therefore, the meas-ured value is multiplied by the factor of 1000 (2) to be converted into the value in the unit ofms. The calculation uses 1 m (1) as the distance between the two points.

To set the distance between the two points in the unit of cm, multiply it by the factor of 100 asthe underlined section in the following program. The unit of speed is set to cm/ms.

To convert the unit of time from s to s (second), multiply values by the factor of 1,000,000(execute 1,000x twice in a program).

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