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source

Syntax​

- source: identifier or expression

Description​

The source operation is one of the few operations that can be used to start the chain of operations that make up a variable.

The source line identifies the data source that will feed the sequence of operations that follows. A valid data source can be a pin, register, or tag name depending on the device being configured. A source can also be another variable name, in which case the final output of the named variable will feed into the start of the new variable's operation chain.

A source can be:

  • A simple name (identifier)
  • A complex expression referencing one or more valid data source identifiers — when any referenced source is updated, the expression is evaluated and the result passed to the next stage
  • A constant (number, boolean, or string) — evaluated once at engine initialization; no updates are emitted from the source

For string constants, use YAML quoting as needed (e.g. 'ACTIVE' or "'ACTIVE'").

Examples​

  var1:
    - source: AIN0

  var2:
    - source: var1

  var3:
    - source: AIN0 + AIN1
info

In the above example, AIN0 and AIN1 are identifiers available in LabJack data sources.