100 Rockwell Automation Publication 1756-UM058G-EN-P - November 2012
Chapter 5 Fast Module Features
If the output logic turns Off before the cycle limit is reached, you can
configure the pulse cycles to continue until the cycle limit is reached by
enabling the Execute All Cycles option. Figure 16
shows a cycle limit of 2
with the Execute All Cycles option enabled.
Figure 16 - PWM Cycle Limit with Execute All Cycles Option
Minimum On Time, Extend Cycle, and Stagger Output
The Minimum On Time, Extend Cycle, and Stagger Output configuration
options are useful in time-proportional control applications, such as temperature
control. In these applications, PID calculations compare the actual temperature
to the desired setpoint and vary the PWM On time to a heating element in real
time to regulate temperature as it approaches the setpoint, as shown in Figure 17
.
Figure 17 - PWM for Time Proportioned Control
Output Logic
Both cycles are executed even though the output
logic turned Off before the cycle limit was reached.
Output State
Heated Vessel
Variable PWM On Time
from PID Calculation
Temperature Feedback to Analog Input
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