Measure HVAC Thermostat Signals

[MeasureGeek]

Hello, 

           I want to measure the 24V AC signals coming out of a wall mounted thermostat in my home for heating, cooling and fan. NI daqs as much as I know have an input voltage range of -10 to 10 V. Any suggestions on how I can use an NI daw to measure these signals? 

Thanks

[WaiLee]

Hi MeasureGeek,

In order to make 24V AC measurements, you may connect the right DAQ device hardware/module which match the input range of your signal.

Here's the C series Voltage Input Modules link with all the listed Analog Input Voltage Range respective to each module:
https://www.ni.com/en-my/shop/hardware/products/c-series-voltage-input-module.html?modelId=122157

Be sure to check whether the module is Input AC or DC Coupling, if it's DC coupling, the module supports both AC and DC signals to pass through a connection whereas AC Coupling only allows AC signals. You may refer to the link below for detailed explanation regarding to Input Coupling:

https://knowledge.ni.com/KnowledgeArticleDetails?id=kA00Z0000019O6oSAE&l=en-MY