Mitsubishi Electric MELSEC FX3U Programming Manual page 862

FX /FX /FX Series Programmable Controllers
3G 3U 3UC
Programming Manual - Basic & Applied Instruction Edition
-Timing chart
X010: Preparation
for measurement
SW(X000,X001)
RST
T246
Current
value of T246
M0
2. Example of program to measure the short pulse width using a high speed ring counter (only
in FX /FX
3U 3UC
Step
0
X010
Interrupt
pointer
X010
I001
Interrupt
pointer
X010
I100
860
I001(Interrupt processing)
Part A in the previous page
2
1
PLCs)
M8099
When the rising edge of
X000 is detected
RST D8099
RST
FNC 03
IRET
When the falling edge of
X001 is detected
FNC 12
M0V
SET
FNC 03
IRET
END
36 Interrupt Function and Pulse Catch Function
36.3 Input Interrupt (Interrupt Triggered by External Signal) [Without Delay Function]
I100(Interrupt processing)
Part B in the previous page
6
5
4
3
Interrupts are enabled by the EI instruction.
FNC 04
The main program is described.
EI
The ring counter is set to ON.
D8099 is set to ON
FNC 06
FEND
When X000 turns ON: The ring counter is reset
M0
Measurement data
When X001 turns OFF: The ring counter value
D8099 D0
Measurement
M0
is completed
The special data register M8099 up-counts the
0.1 ms clock from the next operation cycle after
being driven.
When the count value exceeds "32767", it is
returned to "0".
to OFF, and
measurement is started.
is transferred to D0,
and measurement is
completed.