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Analog Output (Single Sample)

Output single sample to multiple analog channels of data acquisition device

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  • Analog Output (Single Sample) block

Libraries:
Data Acquisition Toolbox

Description

The Analog Output (Single Sample) block opens, initializes, configures, and controls an analog data acquisition device. The opening, initialization, and configuration of the device occur once at the start of the model execution. The block outputs a single sample every time step, synchronously to the hardware, during the model run time.

The block has one or more input ports, depending on the option you choose in its dialog box. It has no output ports. The valid data type of the signal at the input port is double.

The Analog Output (Single Sample) block inherits the sample time from the driving block connected to the input port. Analog output is done synchronously, according to the following diagram.

Timing of synchronous analog output

At the first time step (T1), data is output to the selected hardware channels. The simulation does not continue until data is output to all channels.

Notes

To use this block, you need both Data Acquisition Toolbox™ and Simulink® software.

You can use the Analog Output (Single Sample) block only with devices that support single sample output. To send data using devices that do not support acquisition of a single sample (such as devices designed for sound and vibration), use the Analog Output block.

Some devices are not supported by the Simulink blocks in Data Acquisition Toolbox. To see if your device supports Simulink, refer to Supported Hardware.

Other Supported Features

  • This block supports the use of text accelerator mode, but not Rapid Accelerator or code generation.

  • The block supports the use of model referencing, so that your model can include other Simulink models as modular components.

For more information on these features, see the Simulink documentation.

Ports

Input

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Analog output to generate, specified as doubles. If using only one input port for all channels, provide a 1-by-N vector for a single scan on all N channels.

If using a port for each channel, provide a double value to each port. Multiple ports are named by channel names or device specified channel IDs.

Data Types: double

Parameters

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The device from which you want to generate data. The items in the list vary, depending on which devices you have connected to your system. Devices in the list are specified by adaptor/vendor name and unique device ID, followed by the model name of the device, for example, ni Dev1 (USB-6255). The first available device is selected by default. A CompactDAQ chassis is shown as a single device; vendor name, chassis ID, and chassis model would be shown in the list, for example, ni cDAQ2 (cDAQ-9172).

Device channel selection and configuration table. The channel configuration table lists the hardware channels of your device, and lets you select and configure them. Specify which channels to acquire data from (by default all the channels are selected). The following parameters are specified for each selected channel:

Channel ID — Hardware channel ID specified by the device. The Channel ID column is read-only, and the parameters are defined when the device is selected.

Name — Channel name. By default the table displays any names provided by the hardware, but you can edit the names. For example, if the device is a sound card with two channels, you can name them Left and Right.

Module — Device ID the channel belongs to. The Module column is read-only. If a CompactDAQ chassis is selected, it shows the ID of the CompactDAQ module which the channel belongs to; otherwise the ID of the device.

Measurement Type — Measurement type of the channel. This block supports only voltage measurement types. (For other measurement types, use a DataAcquisition object in MATLAB®.)

Output Range — Output ranges available for each channel supported by the hardware, defined when a device is selected.

Number of input data ports, specified as:

1 for all channels (default) — One input port on the block provides data for all channels. Provide data as a 1-by-N vector for N channels.

1 per channel — N input ports on the block, where N is equal to the number of selected channels. Provide data as a double value to each port. For naming, each output port uses the channel name if one was specified, otherwise the channel ID, for example, ao1.

Block sample time, specifies the sample time of the block during the simulation. This is the rate at which the block is executed during simulation. The default value is 1 (simulation seconds). For more information, see Timing in Hardware Interface Models and What Is Sample Time? (Simulink).

Version History

Introduced in R2016b

See Also

Blocks