Pulse Width Measurement Function; Pulse Width Measurement Function Overview; Pulse Width Measurement Specifications - Mitsubishi Electric FX5 User Manual

24.3

Pulse Width Measurement Function

This section describes the pulse width measurement function.

Pulse width measurement function overview

Pulse width/period measurement of up to 12 channels is possible from the CPU module and the high-speed pulse input/output
module. The pulse width/period measurement function stores the values of 0.5 μs ring counters at the input signal rising edge
and falling edge to special data registers. This function also stores the difference in the counter values (pulse width) between
the rising edge and the falling edge or stores the difference in the counter values (cycle) between the previous rising edge and
the current rising edge to special data registers in units of 0.5 μs.
For the pulse width measurement function, input channel assignments, logical switch, and measurement mode settings are
configured with parameters, and measurements are started/stopped using the HIOEN/DHIOEN instruction.
To use the pulse width measurement function, parameter settings and the HIOEN/DHIOEN instruction are
always required.

Pulse width measurement specifications

This section describes the pulse width measurement function specifications.
Pulse input signals
Pulse width measurements can be used for a maximum of 12 channels. (CPU module 4CH + high-speed pulse input/output
module 2CH × 4 units)
The input device assignment is as follows.
CPU module
CH1 CH2 CH3
X0 to X7 (Any device can be set.)
*1 : Head input number for each high-speed pulse input/output module
■Measurement frequencies
The table below shows the measurement frequencies.
FX5U-32M, FX5UC-32M
X0 to X5
X6 to X7
*1 : Head input number for each high-speed pulse input/output module
■Measurement precision
The table below shows the measurement precision.
Item
Possible measurement range
Maximum measurable signal width
Resolution
Pulse measurements
The pulse width and period are stored in special devices by the END instruction. (Page 265 List of special relays/special
registers)
High-speed pulse input/output module
First module
CH4 CH5 CH6
X+3 X+4
FX5U-64M, FX5U-80M,
FX5UC-64M, FX5UC-96M
X0 to X7

Cycle
Pulse width
*1
Second module Third module
CH7 CH8 CH9
X+3 X+4 X+3
High-speed pulse input/output
*1
module
X+3, X+4

Description
5 μs
5 μs
1073s741ms823μs
0.5 μs
24 HIGH-SPEED INPUT/OUTPUT FUNCTION
24.3 Pulse Width Measurement Function
Fourth module
CH10 CH11 CH12
X+4 X+3 X+4
Measurement frequencies
200 KHz
10 KHz
24
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