Real Time Control

Real Time Control (RTC) allows the state of ancillary regulator structures, such as pumps, blockages, sluice gates and weirs to be changed, according to the state of sensors elsewhere in the network. For example, the output from a flow gauge can be used to determine when a sluice gate should be opened or closed. In this way, it is possible to control flows throughout the system and identify potential storage capacity and the optimal operating patterns for the network.

RTC for regulators in the network is edited in either the RTC Window Editor or the RTC Grid Editor.

Using Real Time Control

RTC can be defined for one or more regulators - control elements that can physically regulate values in the network. The values that can be controlled are:

• Flow
• Depth

• Velocity

Associated with each regulator is a series of components that determine how the regulator is operated. A number of 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. See RTC Range Example for a simple example.

Detailed design of control structures can then be carried out using indirect controllers to monitor the operation of weirs and gates. For example, a sensor downstream from a sluice gate may be set up to check water levels; the current value from the sensor can be used to decide whether the gate should be raised or lowered. See Controllers for information on the use of indirect controllers.

See the RTC Examples section for examples of using the different regulator components. The possible components are:

Range	The definition of a range of acceptable values for variables measured at a control point, such as flow or depth. If the input value is between the minimum and maximum specified, the range returns a logical output of TRUE; otherwise the result is FALSE
Logic Operator	The combination of the output from two Ranges or Logic operators to give a TRUE or FALSE result
Table	A look-up table to translate measured input values (from a Range, Table or Variable) to new output values
Variable	An expression that combines values (from a Range, Table, Logic operator, Variable or constant value) to derive a new value
Controller	A device to control a regulator in order to achieve a defined setpoint
Rule	A rule controls the setpoint of a regulator. When the conditions on which a rule depend are TRUE the rule takes effect
Comment	A remark inserted at any point in the scenario as a reminder of the effect of the components
Member function	A set of membership functions used to define each input and output of the fuzzy logic control algorithm. Each definition has 4 parameters defining a trapezoidal (or triangular) probability function.
Fuzzy rule	A fuzzy rule.

When a simulation is run, the operation of the control elements modified according to the RTC rules is continually checked. At each 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.

Importing and Exporting RTC Data

RTC data can be exported from the network into specially formatted text files with a .RTC extension.

To export RTC data from the network:

1. Select Export | RTC data from the Network menu. A standard File Save dialog will be displayed.
2. Browse for the directory to where the file is to be saved. Enter a file name and click Save.

Alternatively:

1. Right click on the network in the Explorer Window and select RTC data from the popup menu. The Select Network Version and Scenario Dialog will be displayed.
2. Select which scenario is to be exported from the dropdown list. Select which version of the scenario is to be exported by clicking on the # button.

To import RTC data from an RTC file:

1. Select Import | RTC data from the Network menu. A standard File Open dialog will be displayed.
2. Browse for the correct file using the File Open dialog and click Open