Low-level AC measurements

Low-level AC (alternating current or sine-wave) signals can be measured on U terminals. AC generator anemometers typically output low-level AC.

Measurement output options include the following:

• Counts
• Frequency (Hz)
• Running average

Rotating magnetic-pickup sensors commonly generate AC voltage ranging from millivolts at low-rotational speeds to several volts at high-rotational speeds.

CRBasic instruction: PulseCount(). See the CRBasic Editor help for detailed instruction information and program examples: https://help.campbellsci.com/crbasic/cr6/ .

Low-level AC signals cannot be measured directly by C terminals. Peripheral terminal expansion modules, such as the Campbell Scientific LLAC4, are available for converting low-level AC signals to square-wave signals measurable by C terminals.

For more information, see Pulse measurement specifications.