solenoid valve baseline

[lvuser333]

Hi, I know there is a lot of info on solenoid valves on the forums, but I am looking to establish myself a starting point. I need a solenoid valve (or any valve that can be controlled, really) that will allow me to open and close the valve fairly rapidly (less than 1 second) so I can control the level of liquid in a container. There will constantly be liquid on one side (the top side of the valve when in vertical position), and the valve will open for a short amount of time until a few mL are dispensed and then close. I read alot about needing a DAQ or a relay board, but is there anything out there that I can just plug into the wall to power and then have a usb or other wire run to my PXI to easily open and close it? I have PXI card slots 4130,2564,8232,4065,8101.

For example, could I just use something like the coleparmer valve below and just supply 24V from the PXI 4130 to open it and then remove voltage to close it?

http://www.coleparmer.com/Product/Cole_Parmer_Low_Flow_Direct_Lift_Proportioning_Solenoid_Valve_0_02...

http://www.grainger.com/Grainger/RED-HAT-Solenoid-Valve-6WTP4?Pid=search

[p-rose]

The PXI-4130 is capable of sourcing 20V at 2 amp which should be more than adequate to drive the valve (the current requirements are missing from the spec sheet on the website) but it's kind of like bringing a bazooka to a fist fight. The PXI-2564 is better suited becuase its' a simple bank of contacts but you will need an external 24 V supply.

Going USB could add a whole other layer of complexity depending on the device driver. If you have labview and access to the hardware you listed then this type of application is relatively simple to create.

Here is a great article on implementing a closed loop on/off controller: https://decibel.ni.com/content/docs/DOC-16199.

And to answer your orignal question...yes, solenoids usually work as you described - apply power to open, remove it to close.

[lvuser333]

allright, i have a better understanding of how the solenoid valves work i think. So basically if I wanted to use the PXI-2564 i would just hook up a 24V power supply to it (or 120 depending on the valve) and then have it switch between power on and off for the solenoid? And I also found a solenoid valve that has a required 12V input, so I would be able to easily open and close it with the PXI 4130.

http://www.ascovalve.com/Common/PDFFiles/Product/282SERIES_PG26.pdf

thanks for the help

[p-rose · Accepted solution]

Good, but remember a solenoid works by using a magnetic field to move a piece of metal- a lower voltage will require more current to produce the same field strength, you just need to make sure whatever you're going to interface it to can handle the voltage and the current (or power, which is simply volts * current in pure DC).