Configuring Arithmetic Formula-Based Calculated Channels

Add a calculated channel to analyze or scale data from existing hardware channels. A calculated channel produces a new value based on calculations performed on other channels in the system.

  1. On the Channel Specification toolbar, select Add channel » Calculation » Arithmetic formula.
    A calculated channel appears in the Channel Specification under its host system.
  2. Configure the calculated channel.
    1. Specify a name, unit of measure, and description for the calculated channel.
      Note For examples of formula syntax and a list of supported functions, operators, and constants, refer to Calculation Formula Options.
    2. In Formula, specify a formula to apply to data from an existing channel. Suggested formulas appear when you begin typing.
    3. Within the formula, enter the name of a hardware channel whose data you want to manipulate. Ensure that the channel name is enclosed in single quotes. For example, 'ai 0'. You can also input constants, such as pi.
    4. Click Done.
    After you configure the calculated channel, you can see the live value reflecting the formula you applied to your data. You can use the formula-based calculated channel like any other channel defined in the Channel Specification.
Note Calculated channel data is logged with all other channels configured in your Channel Specification. For more information on logging data, refer to Defining Your Test Configuration.
Notice The formula output is capped at 100 kHz unless the following conditions are met.
  • all source channels are from modules in the same chassis
  • all source channels are using the same data rate level (Slow, Medium, Fast)
If you are using PXI modules, all source channels must also be the same model number.