Digital Input/Output (Data Acquisition Toolbox)

Data Acquisition Toolbox

Creating a Digital I/O Object

You create a digital I/O object with the digitalio function. digitalio accepts the adaptor name and the hardware device ID as input arguments. For a list of supported adaptors, refer to The Hardware Driver Adaptor. The device ID refers to the number associated with your board when it is installed. Some vendors refer to the device ID as the device number or the board number. Use the daqhwinfo function to determine the available adaptors and device IDs.

Each digital I/O object is associated with one board and one digital I/O subsystem. For example, to create a digital I/O object associated with a National Instruments board with device ID 1

dio = digitalio('nidaq',1);

The digital I/O object dio now exists in the MATLAB workspace. You can display the class of dio with the whos command.

whos dio
  Name      Size         Bytes  Class

  dio       1x1           1308  digitalio object

Grand total is 40 elements using 1308 bytes

Once the digital I/O object is created, the properties listed below are automatically assigned values. These general purpose properties provide descriptive information about the object based on its class type and adaptor.

Table 7-1: Descriptive Digital I/O Properties
Property Name
Description

Name
Specify a descriptive name for the device object.

Type
Indicate the device object type.

**Table 7-1: Descriptive Digital I/O Properties**
Property Name	Description
`Name`	Specify a descriptive name for the device object.
`Type`	Indicate the device object type.

You can display the values of these properties for dio with the get function.

get(dio,{'Name','Type'})
ans = 
    'nidaq1-DIO'    'Digital IO

Digital Input/Output Adding Lines to a Digital I/O Object