IDEC MicroSmart User Manual

Page 136

5: S

PECIAL

UNCTIONS

5-16

« FC4A M

ICRO

MART

SER

’

ANUAL

Ladder Diagram

When the

MicroSmart

starts operation, reset value 62836 is stored to reset value special internal relay D8046. Gate input

special internal relay M8031 is turned on at the end of the third scan to start the high-speed counter to count input pulses.

Timing Chart

M8120

M8120 is the initialize pulse special internal relay.

1st scan
SUB and ADD instructions are used to store a reset value of 62836
(65535 – 2700 + 1) to D8046 (reset value).

M8031 (gate input) is turned off.

M0 is turned off.

3rd scan
At the rising edge of M0, M8031 (gate input) is turned on. After the
END processing of the third scan, HSC1 star ts counting.

2nd scan
At the falling edge of M8120 (initialize pulse), M0 is turned on.
HSC1 is initialized in the END processing of the second scan.

When HSC1 over flows 65535, output Q1 (comparison output) is
turned on to star t timer T0. HSC1 star ts to repeat counting.

When the timer times out 0.5 sec, M8030 (comparison output
reset) is turned on to turn off output Q1.

END

M8031

SOTU

REP

S2 –

2700

D1 –

S1 –

65535

SUB(W)

REP

S2 –

D1 –

D8046

S1 –

ADD(W)

M8120

SOTD

TIM
5

M8030

Comparison Output Q1

OFF

Current Value D8045

When the high-speed counter current value exceeds
65535, comparison output Q1 is turned on and the
current value is reset to 62836.

Reset Value D8046

62836

65535

0.5 sec for punching

2700 pulses