SubSystem – Subsystem block
Block SymbolLicensing group: STANDARD
Function Description
The Subsystem block is a cornerstone of hierarchical organization of a control (or simulation)
algorithm. It allows embedding a subsystem into another system (or subsystem).
The subsystem contains blocks and their connections. The subsystem is executed as
ordered sequence of blocks during real-time operation of the REX control system.
Therefore it is sometimes referred to as sequence. All blocks from the surroundings of
the subsystem are executed strictly before or strictly after the whole subsystem is
executed.
There are two possible ways of creating a subsystem in the RexDraw program:
- Copy the Subsystem block from the INOUT library to the given diagram (.mdl file). Blocks can be inserted into the subsystem upon its opening (including Inport and Outport blocks).
- Select a group of blocks and use the Create subsystem command (Create subsystem in the Edit menu). The selected blocks are then replaced by the subsystem block, which contains all the original blocks and Inport and Outport blocks for signals crossing the subsystem boundary. Ports for all unconnected inputs and outputs are created as well.
Once a subsystem is created, you can enter it with a double-click.
It is also possible to create the so-called subsystem mask and define parameters whose values can be used inside the subsystem. Select a subsystem block and go to menu EditSubsystem Mask. A dialog appears and you can define parameters and the corresponding descriptions.
Once a mask is created, the subsystem acts just like any other block – double-click it to open the Block properties dialog. You can see the dialog contains the parameters defined in the subsystem mask. If you need to edit the internals of a masked subsystem, select it and go to menu EditLook under Mask.
See Example 0101-02 demonstrating the use of subsystems. The example is contained in the development tools of the REX system.
Inputs
The ordering and names of the inputs are given by the numbers and names of the
Inport blocks contained within the subsystem.
Outputs
The ordering and names of the outputs are given by the numbers and names of the
Outport blocks contained within the subsystem.
Parameters
The parameters of the subsystem are defined by the subsystem mask.
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