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Pulse Outputs Section 5-2
5-2-9 Variable Duty Factor Pulse Outputs (PWM(891) Outputs)
Overview
PWM (Pulse Width Modulation) pulse outputs can be output with a specified
duty factor. The duty factor is the ratio of the pulse's ON time and OFF time in
one pulse cycle. Use the PWM(891) instruction to generate variable duty fac-
tor pulses from a built-in output.
The duty factor can be changed while pulses are being output.
Bit Allocations
Procedure
Specifications
Note The frequency can be set up to 6553.5 Hz in the PWM(891) instruction, but
the duty factor accuracy declines significantly at high frequencies because of
limitations in the output circuit at high frequencies.
5-2-10 Example Pulse Output Applications
Outputting Pulses after a Preset Delay
This example program waits for a preset time (0.5 ms) after the interrupt input
(CIO 0.04) goes ON and then outputs 100,000 pulses at 100 kHz from pulse
output 0.
Word Bit Function
CIO 100 01 PWM output 0
03 PWM output 1
Item Specifications
Duty factor 0.0% to 100.0% in 0.1% increments
(Duty factor accuracy is +1%/−0% at10 kHz, +5%/−0% at
10 to 32.8 kHz .)
Frequency 0.1 Hz to 6,553.5 Hz
Set in 0.1 Hz units. (See note.)
Output mode Continuous mode
Instruction PWM(891)
• PWM output 0 or PWM output 1
• Enable/disable the origin search function.
Execute PWM(891).
Determine the pulse output port.
Wire the outputs.
PLC Setup settings
Ladder program
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