Documentation

Analog Input

Connect to and read from analog input channels

Library

Simulink® Desktop Real-Time™

Description

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

Parameters

Install new board

Click this button to register a board with Simulink Desktop Real-Time.

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 >. When you select a board in the list, the Delete current board and Board setup buttons become active.

Delete current board

Click this button to delete the current board. The initial selection of the list of registered boards changes to < no board selected >, and the Delete current board and Board setup buttons become inactive.

Board setup

Click this button to set up the board.

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

Sample time

Enter a value representing how frequently you want the block to execute and interact with the I/O hardware. The block also synchronizes 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 that you entered in the Fixed step size box in the Configuration Parameters dialog box, or an integer multiple of that value.

Maximum missed ticks

In Normal Mode, enter the number of timer ticks that your model can lag behind the real-time kernel. When the model lags by this number or less, the software assumes that the lag is temporary and 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 External Mode, the software ignores this value.

Show "Missed Ticks" port

In Normal Mode, select this check box to display the number of missed ticks as a block output.

In External Mode, The "Missed Ticks" port displays zero.

Yield CPU when waiting

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

In External Mode, the software ignores this value.

Input channels

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]
Input range

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

If you want the input range to be different for different analog channels, add an I/O block for each different input range.

Block output signal

From the list, choose 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 to +5 volts and of -5 to +5 volts are converted to 0 to +1.

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

Output data type

From the list, select the type of data that the block outputs to the model.

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