Goto, OUTSTD – Signal source or output
Block SymbolsLicensing group: STANDARD
Function Description
The two blocks Goto (signal source) and OUTSTD (standard output) share the same symbol.
They are used for providing signals, either internal or external.
The Goto block can be used in both the REX control system and the Matlab-Simulink environment, the OUTSTD block exists only in the REX control system.
The following rules define how the RexComp compiler distinguishes between the two block types:
- If the parameter GotoTag contains the __ delimiter (two successive ’_’ characters), then the block is of the OUTSTD type. The part of the parameter (substring) before the delimiter (DRV in the example above) is considered to be the name of an IODRV type block contained in the main file of the project. The RexComp compiler returns an error when such block does not exist. If the driver exists in the project, the other part of the GotoTag parameter (following the delimiter, A in this case) is considered to be the name of a signal within the appropriate driver. This name is validated by the driver and in the case of success, an instance of the OUTSTD block is created. This instance collects real-time data from the driver and feeds the data into the control algorithm at each execution of the task it is included in.
- If there is no __ delimiter in the GotoTag parameter, the block is of type Goto. A matching From block with the same GotoTag parameter for which the Goto block is visible is searched. In case it is not found, the RexComp compiler issues a warning and deletes the Goto block. Otherwise an "invisible" connection is created between the corresponding blocks. The Goto block is removed also in this case thus it is not contained in the resulting control system configuration.
The other parameter of the Goto block defines the visibility of the block within the given .mdl file. The TagVisibility parameter can be local, global or scoped, whose meaning is explained in the table below. This parameter is ignored if the block is compiled as the OUTSTD block.
There is no OUTSTD block in the Matlab-Simulink system, even the blocks whose GotoTag parameter contains the __ delimiter are considered to be of the Goto type. This property is suitable for simulation of both the control system and the controlled system. The model can be connected via From and Goto blocks, whose GotoTag parameters include the __ delimiter. Moreover, it is possible to use one .mdl file for both simulation and real time control without any modifications if the controlled system model is "hidden" in a subsystem whose name starts with Simulation. The RexComp compiler ignores (omits) such subsystems. For further details see [2].
Input
value | Signal going to I/O driver or From block. In case of connection to an I/O driver, the type of input is determined by the I/O driver from the GotoTag parameter. | unknown |
Parameters
GotoTag | Reference to a From block with the same GotoTag parameter, which should be connected with the Goto block or a reference to output signal of the REX control system driver, which should send the data from block input to the process. | string |
TagVisibility | Visibility (availability) of the block within the .mdl file. Defines conditions under which the two corresponding Goto and From blocks are reciprocally available: local | string |
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