Mitsubishi Electric MELSEC iQ-F FX5 - Operation of FX3-compatible pulse catch function; Cautions when using the FX3-compatible pulse catch function

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25 HIGH-SPEED INPUT/OUTPUT FUNCTION
25.5 FX3-compatible Pulse Catch Function
Operation of FX3-compatible pulse catch function
Operation of the FX3-compatible pulse catch function is explained below.
Operation of FX3-compatible pulse catch function
When the status of the input (X0 to X7) changes OFFON, a special relay (SM8170 to SM8177) is immediately set to ON by
interrupt processing. Pulse catch operates even when an input interrupt is also set in duplicate with other functions. Note,
however, that the pulse catch must be set with parameters.
■Examples of program
When the status of the X0 changes OFFON, SM8170 is immediately set to ON by interrupt processing. To capture input
again, turn X2 ON to reset SM8170. (X0 is assumed to be set with parameters.)
■Operation diagram
An operation diagram of the above program example is shown below.
Cautions when using the FX3-compatible pulse catch function
• The FX3-compatible pulse catch function operates only when "Interrupt (Rising)" or "Interrupt (Rising) + Pulse Catch" is set
with parameters.
• To capture input again, the special relay that is set must be reset by the program. Accordingly, new input cannot be
captured until the special relay that is set is reset.
• The special relays for FX3-compatible pulse catch are cleared at STOPRUN and a reset.
• The FX3-compatible pulse catch function is executed regardless of the operations of the special relays for disabling
interrupts.
• The FX3-compatible pulse catch function is executed regardless of the operations of the EI, DI instruction.
• For the functions that share inputs with FX3-compatible pulse catch function, refer to Page 290 Functions that share
inputs and outputs.
Reset input
RST
SM8170
X2
SM8170
Y0
X0
Y2
It can be simultaneously used in a program.
SM8170
X0 (input)
X2 (reset)
Input pulse width