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Analog Input

Read from one or multiple analog input channels

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  • Analog Input block

Libraries:
Simulink Desktop Real-Time

Description

The Analog Input block connects to and reads from specific analog input channels from your Simulink® model. After you add an Analog Input block to your model, you can enter the parameters for its I/O driver.

Examples

Real-Time Controller

Real-Time Controller

Build a simple closed-loop real-time controller by using Simulink Desktop Real-Time™.

Real-Time Filter

Real-Time Filter

Build a real-time filter using DSP System Toolbox™ and Simulink Desktop Real-Time™.

Ports

Output

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Result of A/D conversion of an analog signal. The data type and range of the output value depend on the capabilities of the board.

Data Types: double | single | int8 | uint8 | int16 | uint16 | int32 | uint32

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

Enter a channel vector that selects the analog input channels that you are using on this board. The vector can be any valid MATLAB® vector form. For example, to select eight contiguous analog input channels, enter:

[1,2,3,4,5,6,7,8]

or

[1:8]

To select the first three analog input channels, enter:

[1,2,3]

Programmatic Use

Block Parameter: Channels

From the list, select the input range for the analog input channels that you entered for the Input channels parameter. For example, if the board has an input range of ±5 V, select -5 to 5 V.

If you want a different input range for different analog channels, add an I/O block for each different input range. The valid values depend upon the capabilities of the board.

Programmatic Use

Block Parameter: VoltRange

From the list, select from the following options:

  • Volts — Returns a value equal to the analog voltage.

  • Normalized bipolar — Returns a full range value of -1 to +1 regardless of the input voltage range.

  • Normalized unipolar — Returns a full range value of 0 to +1 regardless of the input voltage range. For example, analog input ranges of 0 volts to +5 volts and of −5 volts to +5 volts are converted to 0 to +1.

  • Raw — Returns a value from 0 through 2n -1. For example, a 12-bit A/D converter returns values from 0 through 212 -1 (0 to 4095). The advantage of this method is that the returned value is an integer with no round-off errors.

Programmatic Use

Block Parameter: RangeMode

From the list, select the type of data that the block outputs to the model. The valid values depend on the capabilities of the board.

Programmatic Use

Block Parameter: DataType

Version History

Introduced before R2006a

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See Also

Topics