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Stream Input

Read formatted ASCII data from communication channel

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  • Stream Input block

Libraries:
Simulink Desktop Real-Time

Description

The Stream Input block reads formatted ASCII data from a port or file. After you have added a Stream Input block to your model, double-click the Stream Input block to open the Block Parameters: Stream Input dialog box.

The driver must be one of:

  • Standard Devices > File

  • Standard Devices > Serial Port

  • Standard Devices > TCP Protocol

  • Standard Devices > UDP Protocol

Specify parameter values as required, then click OK or Apply. When you install a UDP device, enter port addresses in decimal format in the Standard Devices UDP Protocol dialog box.

Examples

Stream Input/Output

Stream Input/Output

Transfer data through TCP communication protocol by using ASCII encoding.

Ports

Output

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Data values that were received from the communication channel as formatted ASCII data and decoded according to Format string.

This port signals 1 if the block has new data available and 0 otherwise.

Dependency

When you select Show “Data Ready” port, this port is visible.

This port signals 1 if a data error occurs and 0 otherwise.

Dependency

When you select Show “Data Error” port, this port is visible.

In Connected IO mode, returns the number of timer ticks that your model lags behind the real-time kernel. When the model lags by more than Maximum missed ticks, the software reports an error and simulation stops.

Dependency

When you select Show “Missed Ticks” port, this port is visible.

Data Types: double

Parameters

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When you click Install new board, the software displays a list of manufacturers of supported boards. When you select a manufacturer, the software displays a list of boards available from that manufacturer. When you select a board, the software adds the board to the list of registered boards and makes that board the current board.

By default, the initial selection in the list of registered boards is < no board selected >.

For more information about driver support for I/O boards, see Hardware Support from Simulink Desktop Real-Time.

Dependency

When you select a board in the list of registered boards, the Delete current board and Board setup buttons are available.

Programmatic Use

Block Parameter: DrvName

To delete the current board, click this button. The initial selection of the list of registered boards changes to < no board selected >.

Dependency

To activate this parameter, select a board in the list of registered boards.

When you delete the current board, the Delete current board and Board setup buttons are no longer available.

Programmatic Use

Block Parameter: DrvName

To set up the board, click this button.

A board-specific dialog box opens to set up the board. For more information, see the board manufacturer documentation.

Dependency

To activate this parameter, select a board in the list of registered boards.

To deactivate this parameter, click Delete current board.

Programmatic Use

Block Parameter: DrvAddress
Block Parameter: DrvOptions

Enter a value, in seconds, that represents how frequently you want the block to execute and interact with the I/O hardware. The block synchronizes your model with the real-time clock at this sample rate.

If you are using a fixed-step solver, enter the value that you entered as the Fixed step size configuration parameter or an integer multiple of that value.

Programmatic Use

Block Parameter: SampleTime

In Connected IO mode, enter the number of timer ticks that your model can lag behind the real-time kernel. When the model lags behind by this number or fewer timer ticks, the software assumes that the lag is temporary. It allows the model to catch up, even if the model misses some ticks. When the model lags by more than this number, the software reports an error and simulation stops.

In Run in Kernel mode, the software ignores this value.

Programmatic Use

Block Parameter: MaxMissedTicks

In Connected IO mode, select this check box to send the number of missed ticks to output port Missed Ticks.

In Run in Kernel mode, the Missed Ticks port is zero.

Programmatic Use

Block Parameter: ShowMissedTicks

In Connected IO mode, select this check box to grant other programs more CPU time while the kernel waits for a response from the hardware.

In Run in Kernel mode, the software ignores this value.

Programmatic Use

Block Parameter: YieldWhenWaiting

A character vector or a cell array of character vectors. The block has as many output ports as the number of character vectors. Each vector specifies a data type by name, and optionally the number of items of that data type in an output vector. For example, 'double' means one double value, and '4*int8' means four int8 values.

The values made available on output ports are grouped and typed according to the Block output data types character vectors. For example, if Block output data types is {'2*int8','3*double'}, the block outputs:

  • On output port 1 — an int8 vector of width 2

  • On output port 2 — a double vector of width 3

Programmatic Use

Block Parameter: DataTypes

A specification in the same format used by C library I/O routines like scanf. The format string describes the data to be received. The number of elements in the format string must equal the number of data items specified in Block output data types. If the specifier is %s or %c for string, the created output port of type string only produces string signals. The Block output data types parameter value for this output port must be "1", because strings can only be scalars.

For example, assume that Block output data types is {'2*int8','3*double'} and Format string is '%d %d %f %f %f'. The block reads an ASCII representation of two integers and three doubles. The block makes the resulting values available to the application on:

  • Output port 1 — an int8 vector of width 2

  • Output port 2 — a double vector of width 3

If the data type specified for a value in Block output data types differs from the type of the corresponding element in Format string, type conversion occurs. The block reads data as specified by Format string, converts the data to match the Block output data types, and provides the data to the application on the block output ports.

Programmatic Use

Block Parameter: FormatString

A character vector, cell array of character vectors, or a number. If the value is a character vector, receiving this sequence of characters terminates data input. If the value is a cell array, any character vector in the cell array terminates data input. If the value is a number, data input terminates after reading the specified number of characters.

Programmatic Use

Block Parameter: Terminator

When you select this check box, the block makes visible the output port Data Ready. This port signals 1 when the block has new data available and 0 otherwise.

Programmatic Use

Block Parameter: ShowReady

When you select this check box, the block makes visible the output port Data Error. This port signals 1 when a data error occurs and 0 otherwise.

Programmatic Use

Block Parameter: ShowError

Version History

Introduced in R2007b

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See Also

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