10-04-2012 04:35 PM
I don't have too much experience in Labview and I'm trying to create pitch motion using a pneumatic system including an air compressor, a solenoid valve and a cylinder.
The compressor is made by PowerFist and is capable of storing 5 gallons of air under a rated pressure of 125psi and can deliver 2.5cfm (cubic foot per meter) at 90 psi. The compressed air is sent directly to the solenoid valve. It operates using an electrical motor operating from a standard 110V power outlet. The cylinder has a stoke length of 19.7” and a bore size of 1.6” capable of operating under 130psi.
The solenoid valve used is 5-way 3-position. This means that there are five different ways the air flows inside the solenoid and the solenoid can set in three positions depending on the movement of the mechanical core inside. When air is transferred into the valve the mechanical core moves directing the air to the appropriate ports of the solenoid. The two outputs of the solenoid are sent directly to the pneumatic cylinder where extension and collapsing movements can be performed. The solenoid works off of a 12V supply so I'm using Darlington pair transistor as the firing circuit.
The issue is that prior to connecting the cylinder, the solenoid seems to be working fine as I can hear the "clicking" sound. However, when I try to connect the cylinder, the air compressor causes the cylinder to collapse and expand once, but does not collapse again. I experience the same issue vice versa....so the cylinder expands and collapses only once, but doesn't expand again. My goal is to have the collapsing and expanding motions happen continuously, not only once. I would appreciate any advice as to how I can solve this problem.
I have attached an image showing the connection between the solenoid and cylinder, as well as my Labview file.
10-05-2012 10:38 AM
Your code currently writes [A,B]=[1,1] continuously. When you click the Right it outputs [1,0] and Left [0,1]. As your controls are set to Latch When released, when the Left and Right buttons are clicked it outputs [1,0] or [0,1] for 100ms then goes back to HOLD [1,1]. Is this how you intend? When you say it only does it once, do you mean each time you click the button? From your Word document it looks like you may want to change the mechanical action of your HOLD, Left, and Right controls to Switch When Released so it will stay Left when the button is clicked rather than returning (unless this is not what you want) then it will Hold Left when you click Left and Hold Right when you click Right.
If you would like it to continuously cycle through these states you will need to set up a State Machine, an example can be found here:
If I misunderstood what you are trying to achieve please let me know.
10-05-2012 03:05 PM
Thank you for your reply.
when I say it only does it once , I mean when I run the code and press Right it extends the cylinder (if it is in collapsing position initially) and when I click Left I hear the 'clicking' sound from the solenoid when it has to collapse the cylinder where it does not collapse it !!!
You understood my problem perfectly . I want the program continuesly cycle through the states. meaning that for example , when I click Left it collapse the cylinder and when i click Right it extends it.
10-13-2012 07:07 PM
Thank you apok
this model gives me 3.71 V is there any way I can get maximum voltage ( 5v )?
most likely your solenoid is not ttl compatible...put a 4.7kohm pull up tied to the 5Vdc on the output of the open collector(DO) of the daq..