GPS-X Technical Reference

357 Tools Object
Controller – The controller switch is used to turn the flow timer model ON/OFF.
Flow will be controlled, only when the controller is switched ON.
Manipulated variable with label – This input variable is used to specify the
cryptic variable name of the flow variable that needs to be controlled.
Cycletime – This input variable is used to specify the total duration of the cycle
including the ON and OFF time.
Start time for ON cycle – This input variable controls the start time of the cycle.
Ontime in one cycle – This input variable defines the duration of ON cycle.
Average value of manipulated variable during cycle – This input variable
defines the average flow rate during the whole cycle.
The default setup of the flow controller defines a cycle of total length of 0.05d; the cycle
remains OFF for 0.01d, gets ON at 0.01d and remains ON until 0.04d. The flow is OFF
from 0.4d-0.5d. This cycle then repeats itself.
SCHEDULER MODEL
Some of the operations at wastewater treatment plant follow a repeating schedule. For example,
the sludge wasting schedule may require wasting on the weekdays and no wastage on weekends.
Until now, these repeating schedules were modeled by inputting the scheduled inputs through a
file input. This approach requires preparation of file inputs for the duration of dynamic
simulation. To simplify modelling a repeating schedule, a new scheduler model is implemented in
the toolbox object of the GPS-X. The structure of the scheduler model is generic and can be used
to model cyclic schedules of operation in a treatment plant. The scheduler model can control flow
rates, split ration and any other model input variable.
The scheduler model can be selected by right-clicking on the tool box object and selecting
scheduler. The scheduler model is useful when the treatment plant is operated in a well-defined
cycle containing many different phases and in each phase a set of model variables is manipulated
in a well-defined manner. In the current scheduler model, a set of 15 model variables can be
manipulated to define complex operational schedules in treatment plants.
GPS-X Technical Reference