Mitsubishi Electronics FX5 ユーザーズマニュアル

19  BUILT-IN I/O FUNCTION

19.3  Pulse Width Measurement Function

The pulse input logic can be switched.
Positive logic or negative logic can be set for each channel with parameter settings.

■Operation for positive logic

■Operation for negative logic

The pulse width measurement mode can be set.
The table below shows the measurement modes for pulse width measurements.

The measurement mode can be changed during pulse measurements by using a special relay. (Page 177 
List of special relays/special registers)

In a user program, the delay time between signals can be calculated from the rising or falling ring counters of 2 inputs. 
(Page 183 Examples of program)

The pulse measurement function execution procedure is shown below.

Check the pulse measurement specifications.

Check the specifications such as the measurement frequency of pulse measurements. (Page 174 Pulse width 
measurement specifications)

Connect the CPU module to the external device.

For details on wiring to external devices, refer to the following manual
MELSEC iQ-F FX5U User's Manual (Hardware)
MELSEC iQ-F FX5UC User's Manual (Hardware)

Set the parameters.

Configure the parameters such as the pulse measurement channel settings. (Page 176 Pulse width measurement 
parameters)

Create the program.

Create the program for using pulse measurements.

Run the program.

1 time measurement mode

Measures the pulse width and period only once from the start of the measurement.

Always measurement mode

Constantly measures the pulse width and period.

Pulse input

Pulse width

Cycle

Pulse input

Pulse width

Cycle