Digital tables in LabVIEW contain data across eight digital states that you can plot on a digital waveform graph. Digital waveform controls and digital data controls both use digital tables in their underlying structure.

You can create a digital table in the following ways:

  • Build a digital table manually
  • Convert analog data to digital data
  • Acquire a digital signal

Digital tables record the following states:

Table 8. Digital Table States
Value Digital Data State Description
0 0 (Drive Low) Force logic low. Drive to the low voltage level (VOL).
1 1 (Drive High) Force logic high. Drive to the high voltage level (VOH).
2 Z (Force Off) Force logic high impedance. Turn the driver off.
3 L (Compare Low) Compare logic low (edge). Compare for a voltage level lower than the low voltage threshold.
4 H (Compare High) Compare logic high (edge). Compare for a voltage level higher than the high voltage threshold.
5 X (Compare Unknown) Compare logic unknown. Do not compare.
6 T (Compare Off) Compare logic high impedance (edge). Compare for a voltage level between the low voltage threshold (VOL) and the high voltage threshold (VOH).
7 V (Compare Valid) Compare logic valid level (edge). Compare for a voltage level either lower than the low voltage threshold (VOL) or higher than the high voltage threshold (VOH).

To build or modify a table of digital data, complete the following steps.

  1. Add a Build Digital Data function to the block diagram.
  2. Optional: If you want to modify existing digital data, wire the digital data input.
  3. Right-click the data input and select an option.
    • Define a constant value: Create » Constant.
    • Allow a user to manipulate the value: Create » Control.
  4. Enter values in the 2D data array.
    Each row in the 2D array represents a single binary value for one sample of data with the most significant bit of data in the first column and the least significant bit of data in the last column. Each value represents a specific digital data state. Valid values include 0-7, as indicated in Table 8. Digital Table States.
    Tip If you wire an array constant to the data input, you can use the digital ring constant to simplify entering digital data in the array. The digital ring constant allows you to select from the 8 digital data states.

    To use the digital ring constant, right-click a value in the array and select Replace to display a temporary version of the Functions palette. Navigate to the Digital Waveform palette and select the digital ring constant. LabVIEW converts any numeric values you previously entered to their corresponding digital data states.

  5. Optional: If you want to compress the digital data, define non-incremental transitions:
    1. Expand the node to display an unwired data input.
    2. Click the input and place a checkmark next to transitions to display the transitions input.
    3. Wire the transitions input to define non-incremental transitions.
      The transitions array must contain the same number of rows as the data array.
  6. To create an empty digital table, right-click the digital data output and select Create » Indicator.
  7. Run the VI to display the data in the digital table.