Operation Of Fx3-Compatible Pulse Catch Function; Cautions When Using The Fx3-Compatible Pulse Catch Function - Mitsubishi Electric FX5 User Manual

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 after execution of the EI instruction, 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 after execution of the EI instruction, 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.)
SM400
X0
SM8170
X2
RST
Reset input
■Operation diagram
An operation diagram of the above program example is shown below.
EI
X0 (input)
SM8170
X2 (reset)

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.
• For the functions that share inputs with FX3-compatible pulse catch function, refer to Page 248 Functions that share
inputs and outputs.
EI
It can be simultaneously used in a program.
Y2
Y0
SM8170
Input pulse width
24 HIGH-SPEED INPUT/OUTPUT FUNCTION
24.5 FX3-Compatible Pulse Catch Function
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