modes

Declare operating modes in mode chart

Parent Section: modecharts

Syntax

modes
    mode m1
    ...
    end
end

Description

modes begins a modes declaration section in a mode chart. The modes section, terminated by an end keyword, can contain one or more mode constructs. Each mode construct declares one mode.

For example, the following syntax declares two modes, m1 and m2.

modes
    mode m1
    ...
    end
    mode m2
    ...
    end
end

mode is a named construct. It is terminated by an end keyword. Each mode declaration contains a complete set of equations that describe this operating mode.

modes
    mode m1
       equations
       ...
       end
    end
    mode m2
       equations
       ...
       end
    end
end

For every mode, the total number of equation expressions, their dimensionality, and their order must be the same. This restriction is the same as for the equations in different branches of the if-elseif-else statement.

This restriction does not apply to the assert expressions, because they are not included in the expression count.

A mode declaration can contain an entry section, which lets you specify the actions to be performed upon entering the mode. These actions are event variable updates based on the value of a continuous variable immediately before entering the mode.

modes
    mode m1
       equations
       ...
       end
    end
    mode m2
       entry
       ...
       end
       equations
       ...
       end
    end
end

The entry section is separate from the equations section, and the event variable updates in the entry section are not counted in the number of equation expressions for the mode.

To implement a state reset, mode charts can contain instantaneous modes and compound transitions. An instantaneous mode is a mode that is active only for one event iteration. You declare instantaneous modes the same way as regular modes, using the same syntax. The same mode can be used as an instantaneous mode in one case and a regular mode in another, depending on the transitions declared in a mode chart. To specify that a mode is instantaneous, list it as the middle mode in a compound transition.

For a detailed example of using modes, see Switch with Hysteresis.

Examples

• Switch with Hysteresis

Version History

Introduced in R2017a