Using AO for Duty Cycle Control

1
Using AO for Duty Cycle Control

• Percent time on (ON_TIME) over the duty cycle
  period is determined by AO setpoint.
• Automatically repeats at end of duty cycle using
  current value of ON_TIME
• High resolution of on-off time

ON
OFF
time on
Duty Cycle Period
2
Duty Cycle Control DO Setup

• Typical application is manipulation of heater
  band input for extruder temperature control
• Percise adjustment to ½ of 60 hz since timing is
  done by DO card hardware
• Percent time on is determined by AO output
  configured to reference the discrete channel

3
Duty Cycle Control DO Setup

• Period of duty cycle is determined by
  PULSE_PERIOD configured for the DO channel
• Period should be set to match the period of
  execution of the module that contains the AO
  block that references the DO channel

4
Duty Cycle Configuring AO

• When you browse to a DO channel when configuring
  the AO block, the only selection is ON_TIME

5
AO With Increase-Decrease Actuator