Ancillaries and Real Time Control - About Real Time Control (RTC)

Real Time Control, or RTC, allows the state of ancillaries such as pumps, blockages, sluice gates, and weirs to be changed according to the state elsewhere in the network. Ancillary links that can be controlled via RTC are referred to as regulators.

For example, the flow in a conduit can be used to determine when a sluice gate should be open or closed. In this way, it is possible to actively control flows throughout the system.

Associated with each regulator is a series of components that determine how the regulator is operated. Several simple components can be combined to build up complex instructions.

The simplest form of RTC uses direct control, where the structure is under the direct control of the regulator. For example, a pump can be switched on or off, depending on the level in the upstream chamber.

Detailed design of control structures can be carried out using indirect controllers to monitor the operation of weirs and gates. For example, a node downstream from a sluice gate may be set up to check water levels. The current value from the node can be used to decide whether the gate should be raised or lowered.

When a simulation is run, the operation of the control elements modified by RTC rules is continually checked. At each major timestep, the simulation engine works through each of the components in turn, for each regulator. The engine checks the ranges, combines the TRUE or FALSE outputs in any logical operators, translates the values using the tables, and recalculates any variables. The rules are then applied, and the operation of the regulators is modified accordingly.

A presentation slide about the RTC Window Editor, where Real Time Control rules of regulators in the network can be viewed and edited, with an image of an example configuration.

The following regulator components can be used in an RTC:

A presentation slide about the Range regulator component, which provides a range for variables measured at a control point, such as flow or depth, against which a true or false statement is produced; with an image of example settings.

A presentation slide about the Logic Operator regulator component, which can be a combination of logic from up to four ranges that give a true or false result; with an image of example settings.

A presentation slide about the Controller regulator component, which indirectly controls a regulator to achieve a defined setpoint; with an image of example settings.

A presentation slide about the Table regulator component, which translates measured input values from the control point to the new output values; with an image of example settings.

A presentation slide about the Variable regulator component, which allows for a combination of values to derive a new value; with an image of example settings.

A presentation slide about the Rule regulator component, which controls the setpoint of a regulator and includes three types—control, position, or switch on/off; with an image of example settings.

A presentation slide about Regulator Events, which provide direct and indirect control of the regulator structures and can be used instead of RTC or can override RTC; with an image of the Event Editor and the Regulator Pump properties dialog box.

Putting this all together, look at this RTC Window Editor to see how two examples are constructed.

The RTC Window Editor with regulator components configured for this example, and in the Description box, the logic of the defined rules in plain English.

The first regulator link, Storm_tank1.1, is a variable sluice gate. There is a defined range that monitors whether the elevation of water is above 41.000m. The default rule for the sluice is to have a set opening of 0.000m, or to be fully shut. When the inlet range becomes true, meaning the water level is below 41.000m at the node, then the sluice opening will be set to 0.150m.

The second example is similar, but this time, it employs a logic operator, which is reading in the Pump2On range from a global item. This means it could be used by another regulator. There is a default opening of 0.300m, which will initially close to 0.100m when the depth in the tank is exceeded. If the depth in the tank is exceeded and the Pump2On condition is met, then the sluice will further close to 0.050m.

Read the Description text to see the logic of the defined rules in plain English.

About Real Time Control (RTC)

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