Controls

Controls allow you modify the state of one or more elements in the system when certain criteria are met (for example, to turn a pump on when the water in a tank drops below a certain level). Controls are typically utilized when performing an Extended Period Simulation.

There are two types of controls: Simple and Logical.

Simple Controls

Simple Controls are defined as:

IF <regular condition> THEN <regular action>

Where:

<regular condition> is the criteria to be satisfied.

<regular action > is the modification to be performed.

Note: Simple Controls can optionally be evaluated during a Steady State analysis. Refer to the Use simple control during steady state option.

Note: Simple Controls do not support composite conditions or composite actions, and have some limitations related to the condition criteria (refer to the Regular Condition topic below).

Logical Controls

Logical Controls are defined as:

IF <condition> THEN <action> (Optional) ELSE <action> (Optional) Priority <priority value>.

Where:

<condition> is the (regular or composite condition) criteria to be satisfied.

<action > is the modification to be performed

<priority value> optional value between 1 and 5 (5 being the highest).

The optional ELSE action allows you to specify an action to be performed when the condition is not met.

Note: Logical Controls are not evaluated during a Steady State analysis.

Conditions

Conditions allow you to specify when something should happen. There are two types of conditions, regular and composite.

Regular Condition

Regular conditions can be one of two types: Element or System.

Element based conditions support the following criteria:

Junctions, Tanks, Reservoirs: Demand, Hydraulic Grade, Pressure.
Tanks additionally support: Level, Time to Fill, Time to Drain.
Pipes: Flow, Status.
Pumps, Valves: Flow, Status, Setting.

System based conditions support the following criteria:

Total System Demand, Time from Start (of simulation), Clock Time.

Note: Simple Controls only support the following element criteria: Junction and Tank Hydraulic Grade, and Pressure.

Note: Simple Controls only support the following system criteria: Time from Start and Clock Time.

Composite Condition

A composite condition is comprised of any number of regular conditions (using logical AND or OR operators). Refer to the Edit If Condition Dialog to create a composite condition.

Note: When specifying AND and OR operators in a composite condition, the OR operator takes precedence.

IF a OR b AND c

is interpreted as:

IF (a OR b) AND c

If the condition should be interpreted as shown below, define two controls that perform the same action.

IF a OR (b AND c)

Note: Simple controls do not support composite conditions.

Actions

Actions allow you to specify what happens when a condition is met. There are two types of actions regular and composite.

Regular Action

Regular actions support the following modifications:

Pipe: Status.
Pump, VSPB: Status, Speed Setting, Hydraulic Grade, Pressure.
Valve: Status, Setting.

Composite Action

Composite actions are comprised of multiple regular actions (allowing you to define a control that performs multiple actions when a condition is met). Refer to the Edit The/Else Action Dialog to create a composite action.

Note: Simple controls do not support composite actions.

Priority

Priorities are only supported for logical controls and allow you to specify which control takes precedence if multiple control conditions are met and have conflicting actions.

Logical controls have a default priority of 0. You can optionally assign a priority of 1-5 (5 is the highest priority). Controls with identical priorities will be prioritized based on the order they were defined.

Note: Relative speed pump patterns take precedence over any controls that are associated with a pump.

Example

To create a logical control to turn a pump (PMP-1) on when the level in a Tank (T-1) falls below a specified value (5 ft.) or when the system demand exceeds a certain amount (5000 gpm):

IF {T-1 Level < 5 ft.} OR {System Demand > 5000 gpm} THEN {PMP-1 Pump Status = ON}