The Digital Reader display show the line states of digital inputs being read from the NI myDAQ. Each of the eight line state led indicators turns on (bright blue) if the line being read is high (between 2V and 5V), or turns off (dark blue) if the line is low (between 0V and 0.8V). The display also gives the numeric value of the digital port being read.
Note that the Numeric value is given in hexadecimal representation, and that one hexadecimal digit will represent lines 4-7 and a second digit will represent lines 0-3. If only four lines of the digital port are being read, then the Numeric Value will be a single hexadecimal character calculated from only the 4 digital lines being used.
The configuration settings for the ELVISmx Digital Reader contains only one input, and allows the user to select which lines to read from the digital port of the side of the NI myDAQ unit. The available options are: 0-3, 4-7, and 0-7.
Note that any digital lines that are being read using the ELVISmx Digital Reader will be reserved while the digital reader is running, and will not be available to the ELVISmx Digital Writer, or to any other program. To use the ELVISmx Digital Reader and Digital Writer at the same time, use lines 0-3 for one of the instruments, and lines 4-7 for the other.
The Instrument Control settings section of the Digital Reader allows the user to select which device they are using to take a measurement and if they’d like to acquire one sample or acquire continuously. This section also holds the run and stop buttons for the Digital Reader and a link to the help section for the Digital Reader in the NI ELVISmx help.
The device drop down selection box allows a user to select any myDAQ or ELVIS unit that is connected to the system. The device list, which includes the device numbers, is pulled from the devices and interfaces that can be seen in Measurement and Automation Explorer. To test or rename each device, see the Configuring and Testing your myDAQ in Measurement and Automation Explorer page.
The acquisition mode drop down selection box gives two options: run continuously, and run once. When run continuously is selected, the Digital Reader will start running as soon as the Run button is pressed, and will continue to make measurements until the Stop button is pressed. When run once is selected from the Acquisition Mode list, the Digital Reader will take a single measurement when the Run button is pressed, and will then stop executing automatically.