Precautions
If high-speed pulse input/output module operates in an interrupt program with the priority 1, operation error (3580H) occurs.
The high-speed pulse input/output module operates in an interrupt program with the priority 2 or 3.
24.4
Pulse Catch Function
This section explains the pulse catch function.
Outline of pulse catch function
The pulse catch function enables pulse signals that are incompletely sampled in regular input processing to be caught. Inputs
X0 to X17 on the CPU module and all inputs on the high-speed pulse input/output module can be used on up to 40 channels
(CPU module: 8 points, high-speed pulse input/output module 8 points × 4 units).
To use the pulse catch function, pulse catch setting and the input response time must be set with parameters.
An FX3-compatible pulse catch function is mounted on only the CPU module. For details of functions, refer to Page 281
FX3-Compatible Pulse Catch Function.
The pulse catch function and FX3-compatible pulse catch function can be used simultaneously.
Specifications of pulse catch function
The specifications of the pulse catch function are explained below.
Performance specifications
Pulse catches can be used on inputs X0 to X17 of the CPU module and all inputs on the high-speed pulse input/output
module.
■Input response time
Input response times are shown below.
FX5U-32M, FX5UC-32M
X0 to X5
X6 to X17
*1 : Head input number for each high-speed pulse input/output module
■Detectable pulse width
Pulse widths that satisfy the following condition can be detected.
Pulse input ON width > input response time
Pulses cannot be detected normally if the above condition is not satisfied. Set the input response time so that
the above condition is satisfied.
24 HIGH-SPEED INPUT/OUTPUT FUNCTION
276
24.4 Pulse Catch Function
FX5U-64M, FX5U-80M,
FX5UC-64M, FX5UC-96M
X0 to X7
X10 to X17
High-speed pulse input/output
*1
module
X to X+5
X+6, X+7
Input response time
5 μs
100 μs