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Pulse Outputs Section 5-3
5-3-9 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
Restrictions on the PWM(891) Outputs
• In the Y CPU Units, PWM outputs 0 and 1 cannot be used for pulse out-
puts 2 and 3 if the origin search function is enabled for pulse outputs 2
and 3.
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.
Word Bit Function
CIO 101 00 PWM output 0
01 PWM output 1
• PWM output 0 or PWM output 1
• Disable the origin search function for pulse
outputs 2 and 3.
Note: Disable the origin search function because the PWM output
shares the output with the origin search function's Error
Counter Reset Output and both cannot be used
simultaneously.
Execute PWM(891).
Determine the pulse output port.
Wire the outputs.
PLC Setup settings
(Y models only)
Ladder program
Item Specifications
Duty factor 0.0% to 100.0% in 0.1% increments
(Duty factor accuracy is ±5% at 1 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)
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