Stream Output

Write formatted ASCII data to communication channel

• 

Libraries:
Simulink Desktop Real-Time

Description

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

The driver must be one of:

• Standard Devices > File

• Standard Devices > Serial Port

• Standard Devices > TCP Protocol

• Standard Devices > UDP Protocol

When you install a UDP device, enter port addresses in decimal format in the Standard Devices UDP Protocol dialog box.

Any serial output port can send data with sample rates up to 500 Hz. To enable a faster sample rate of up to 10 kHz for some output serial ports, click Install new board, select Standard Devices > Serial Port, and select Direct port access.

The block does not support this option with all types of serial output hardware.

Examples

Stream Input/Output

Transfer data through TCP communication protocol by using ASCII encoding.

• Open Script

Ports

Input

Input Data — Data to write to communication channel

numeric vector | string

Data values that are sent to the communication channel as ASCII data, encoded according to Format string.

Output

Data Ready — Data ready port (optional)

1 | 0

This port signals 1 if the block is ready to accept new data and 0 otherwise.

Dependency

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

Data Error — Data error port (optional)

1 | 0

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

Dependency

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

Missed Ticks — Missed tick count (optional)

double

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

Install new board — Register a board

< no board selected > (default)

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

Delete current board — Delete the current board

(button)

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

Board setup — Set up the board

(button)

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

Sample time — Sample time of block

0.1 (default) | double

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

Maximum missed ticks — Number of timer ticks by which your model can trail the kernel

10 (default) | integer

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

Show “Missed Ticks” port — Send number of missed ticks to port Missed Ticks

'off' (default) | 'on'

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

Yield CPU when waiting — Yield CPU while kernel waits for hardware

'off' (default) | 'on'

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

Input port sizes — Specify number and width of ports

1 (default) | vector

Enter a port width, or vector of port widths. The number of elements determines the number of input ports. Each port has the width specified by the corresponding element. For example, specifying [3,1,2] indicates that the block has three input ports: a vector of width 3, a scalar, and a vector of width 2, for a total of six elements. You specify only the widths.

Programmatic Use

Block Parameter: PortSizes

Format string — Format of data items being written to the stream

'%g' (default) | character vector

Enter a specification in the same format used by C library I/O routines like printf. The format string describes the data to be sent. The format string must have the same number of specifiers as the sum of the elements of Input port sizes. If the specifier is %s or %c for string, the created input port of type string only accepts string signals. The Input port sizes parameter value for this input port must be "1", because strings can only be scalars.

For example, assume that Input port sizes is [3,1,2]. Then a Format string of '%d %d %d %f %d %d' outputs ASCII representing:

• Three integers from the vector on the first input port

• One double from the scalar on the input second port

• Two integers from the vector on the third input port

If the data type specified in the Format string for a value differs from the type of the actual value, type conversion occurs. Converted data that conforms to the Format string is output as ASCII to the device.

Programmatic Use

Block Parameter: FormatString

Show “Data Ready” port — Add port Data Ready that signals 1 when the block can accept new data

'off' (default) | 'on'

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

Programmatic Use

Block Parameter: ShowReady

Show “Data Error” port — Add port Data Error that signals 1 if error occurs

'off' (default) | 'on'

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

Initial string — Data to send when simulation begins

character vector

Optional. Enter a character vector. When simulation begins, send the specified data before the other data that is sent during simulation.

The character vector can contain anything. You can use it to initialize a device. It is sent literally as specified, without reference to Format string.

Programmatic Use

Block Parameter: InitialValue

Final string — Data to send when simulation ends

character vector

Optional. Enter a character vector. When simulation ends, after the other data that is sent during simulation, send the specified data.

The character vector can contain anything. You can use it to shut down a device. It is sent literally as specified, without reference to Format string

Programmatic Use

Block Parameter: FinalValue

Version History

Introduced in R2007b

R2024b: Update to blocks with port names

In R2024b, when you enable optional ports, such as Show "Missed Ticks" port, these Simulink^® Desktop Real-Time™ block ports appear with labels.

R2019b: Stream Input and Stream Output Blocks Support String Signals

The Stream Input block and Stream Output block support Simulink string signals.

R2019a: RS-232 Serial Port Drivers Support for macOS

The serial port drivers for the Packet Input block, Packet Output block, Stream Input block, and Stream Output block support macOS systems. In previous releases, the serial port drivers for these blocks supported Windows^® systems only.

R2018a: TCP and UDP Protocol Support for Stream Input and Stream Output

The TCP protocol and UDP protocol drivers for the Stream Input block and Stream Output block are available from the Standard Devices list. From the Install new board button, select Standard Devices > TCP Protocol or select Standard Devices > UDP Protocol.