144 Program features
Example
The time scheme below visualizes the operation of the sleep function.
Sleep function for a PID controlled pressure boost pump (when parameter
is set
to
): The water consumption falls at night. As a consequence, the PID
process controller decreases the motor speed. However, due to natural losses in the
pipes and the low efficiency of the centrifugal pump at low speeds, the motor does not
stop but keeps rotating. The sleep function detects the slow rotation, and stops the
unnecessary pumping after the sleep delay has passed. The drive shifts into sleep
mode, still monitoring the pressure. The pumping restarts when the pressure falls
under the allowed minimum level and the wake-up delay has passed.
Wake-up level deviation
t
<
t
sd
Output frequency
Selected process
actual value
Stop
t
sd
= Sleep delay (
Sleep level
(
)
Start
Wake-up delay
t
sd
Reference
Time
Sleep boost step (
)
Control panel
display:
PID
SLEEP
Sleep boost time (
)
Time
Time
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www.aotewell.com
Industry Automation
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