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Stream Input

Receive formatted ASCII data

Library

Real-Time Windows Target™

Description

The Stream Input block receives formatted ASCII data. 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 Standard Devices > Serial Port, Standard Devices > File, or 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.

The parameters are:

Parameters

Sample time

Enter a value representing how frequently you want the block to execute and interact with the I/O hardware. The block will also synchronize your model with the real-time clock at this sample rate.

    Tip   If you are using a fixed-step solver, you must enter the value you entered in the Fixed step size box from the Configuration Parameters dialog box, or an integer multiple of that value.

Maximum missed ticks

Enter the number of timer ticks that your model can lag behind the real-time kernel. When the model lags by more than this number, the block reports an error and simulation stops. Otherwise, simulation continues even if some ticks are missed.

Show "Missed Ticks" port

Select this check box to display the current number of missed ticks as a block output.

Yield CPU when waiting

Select this check box to grant other programs more CPU time while the kernel waits for a response from the hardware.

Block output data types

A string or a cell array of strings. The block has as many output ports as the number of strings. Each string specifies a data type by name, and optionally a number of elements. 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 strings. For example, if Block output data types is {'2*int8','3*double'}, the block outputs an int8 vector of width 2 on the first output port, and a double vector of width 3 on the second output port.

Format string

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 string must equal the number of data items specified in Block output data types.

For example, if 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 in an int8 vector of width 2 on the first output port, and a double vector of width 3 on the second output port.

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 automatically. 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.

Message termination

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

Show "Data Ready" port

If enabled, the block has an output port that signals 1 if the block has new data available, and 0 otherwise.

Show "Data Error" port

If enabled, the block has an output port that signals 1 if a data error has occurred, and 0 otherwise.

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