Pneu to pneumatics

[jfitz0807]

I haven't been able to find this on screenstepslive. We have a spike wired to our compressor. The Compressor class in java also requires a digital input to tell when to turn off the compressor. What should we use to provide this signal?

Also, we would like to be able to set the pressure to two different settings; one for passing and one for shooting. If I use the high pressure, for the digital input to my compressor class, I figured I could use the low pressure digital input as a separate input that would shut off the compressor at the lower pressure setting.

How does one adjust the pressure set point on the KOP pressure switches? One of our students tried adjusting the set screw, but the set point didn't seem to change from about 100psi.

[cgmv123]

The digital pressure switch is what goes into the digital input to control the pressure. It has to be able to shut off at 120 psi.

You can't have 2 different pressures feeding the same cylinder.

I'm not sure which KOP pressure switches have set screws and are uncalibrated. The relief valve, which vents excess pressure, doesn't have a set screw, but may come uncalibrated. One of the hex rings loosens the switch, another does the actual adjustment, and the last is rigid for fitting the valve onto the compressor or fitting.

[steinra]

Make sure to look at the pneumatics section in the rules as it will help with the wiring question you have. But to help answer it, there is a pressure switch that is in the high side of the circuit that will change states when 120 PSI is hit. This single is passed to a digital input that you specify on the constructor in java for the compressor class.

I will let others talk to the rest of your question on if it can be done legally or not per the rules.

Randy

[Bruceb]

Not sure you really want to change the pressure by controlling the compressor. They are not the highest volume compressors and take a long time to charge a system. What you can do is have a high and low pressure leg on your pneumatics system. Just have 2 outputs from your storage tank feeding 2 pressure regulators set at different pressures. One goes to your high pressure solenoid and the other to your low pressure solenoid. Just remember to have a gauge attached to each regulator.
This is from the pneumatics manual and will help wiring the pressure switch.

We have included a pressure switch manufactured by Nason. This switch is normally
closed. The switches will open at approximately 115 psi and will not close again until the
pressure drops to approximately 95 psi. This will allow you to turn off the compressor once
you are up to 115psi, saving power in the battery. It must be wired directly to a digital
input and ground port on the Digital Sidecar. No specific GPIO port is designated for the
pressure switch. The cRIO must be programmed to react to the GPIO port that is connected to the
pressure switch. The cRIO will activate the designated Spike Relay to turn the compressor “on” and
“off”. There is no default program in the cRIO to control the compressor power. Do not put the pressure
switch in series with the power supply to the compressor.


Hope that helps.

[Jon Stratis]

You should have a pressure switch (http://www.andymark.com/product-p/am-2006.htm) that connects to the DIO. Wire it between ground and signal.

[brycen66]

You can switch between two pressures. It is actually quite simple. using a single solenoid manifold, You can achieve this using the exhaust ports as inputs and the pressure port as an exhaust.