Chapter 8 High-Speed Counter Function; Overview - Mitsubishi Electric MELSEC-L02SCPU User Manual

CHAPTER 8
8.1

Overview

(1) Definition
This function counts the number of high-speed input pulses that cannot be measured by general counter.
(2) Features
The high-speed counter function is controlled by parameters and dedicated instructions.
Encoder
(pulse generator)
(a) Pulse inputs from two channels
Pulses can be simultaneously input from two pulse generators.
(b) Five operation modes
According to the application, an operation mode can be selected from the following five modes:
• Normal mode: used for operating the CPU module as a general high-speed counter.
• Frequency measurement mode: used for measuring frequencies from the number of input pulses.
• Rotation speed measurement mode: used for measuring a rotation speed from the number of input pulses.
• Pulse measurement mode: used for measuring the on width or off width of input pulses. This mode is
suitable for measuring the length of an object and others.
• PWM (pulse width modulation) output mode: used for outputting pulses with the on width and cycle time
set. This mode is suitable to use the CPU module as an oscillator and others.
(c) Combined use of functions
Functions for preset, count stop, and counter value latch can be used in combination (counter function
selection).
(d) Execution of an interrupt program
An interrupt program can be executed when the current value and a set value match in the counter
(coincidence detection interrupt function).
(e) Signal output
A coincidence signal can be output when the current value and a set value match in the counter. (coincidence
output function).
HIGH-SPEED COUNTER FUNCTION
Encoder (pulse generator)
CH2
CH1

CHAPTER 8 HIGH-SPEED COUNTER FUNCTION

LCPU
PWM output mode
PWM output ON time
PWM output on time setting
setting
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