NI 9474 24VAC

[StevenHowell]

Good morning,

I have an NI 9474 module that I would like to use to control some sprinkler solenoid valves. the solenoids require 24VAC. I see in the documentation for the 9474 that it specifies up to 30VDC, but doesn't mention anything in regards to AC voltage. 

I have to ask, even though it is not stated, will the 9474 work with 24VAC? 

[kaschmidt]

Hi Steven,

Do you have a driver circuit for the solenoid or are you hoping to have the module drive the solenoid directly?

Is there an external power supply that is powering the solenoid?

Is your device level controlled?

Regarding the spec sheet for the 9474, this module is a digital output meaning that the module acts as a switch. You can programmatically control the output based on this switch, however, the output will be either "on" which will output a DC voltage equivalent to your input voltage, or "off".

Regards,

Austin Schmidt

Applications Engineering

National Instruments

[StevenHowell]

Good morning Austin,

Sorry for the delayed response, I've been moving and haven't had internet for a few days. 

I would like to drive the solenoids directly from the 9474 and was going to wire in the 24VAC to the Vsup and COM terminals. 

If that wont work, I will probably have to get some 24V relays to close the 24VAC circuit for the sprinkler valves. 

[kaschmidt]

Hi Steven,

You would need to wire in a DC signal as it sounds as if you need to maintain a constant voltage level to drive the solenoid. Again, the digital module will act as a switch in that when you programmatically turn the state to "on" it will output the corresponding input voltage that you have at the source.

Regards,

Austin