programming pneumatics psi

[thatoneguy23]

Our programmer needs to know how to program our pneumatics to shut down at 60 psi.

We use labview

[MrForbes]

The pressure switch that comes in the KOP is set for about 115-120 psi. There is a pressure regulator that you need to use to reduce this to a working pressure of 60 psi or less. And there is another regulator you can use to reduce it further for other purposes.

If you want to limit the high pressure storage part of the system to 60 psi, you'll probably need to get a pressure switch or transducer that is set to 60 psi, or a transducer that can measure the pressure. But you'll probably find out that you really just need to understand the pneumatic system fully, and that you don't need to bother with extra switches.

[Al Skierkiewicz]

The running test you will be required to demonstrate during inspections is that when you enable the robot, the compressor turns on and pressurizes to 120 psi (or slightly less) as verified by the high side gauge and then shuts off under Crio control. While this test is running your inspector will also examine the low side gauge to insure that the pressure there rises to 60 psi and no higher. Then you will be asked to disable the robot and vent the pressure at which time both gauges should return to zero.

[Daniel_LaFleur]

Originally Posted by Al Skierkiewicz

The running test you will be required to demonstrate during inspections is that when you enable the robot, the compressor turns on and pressurizes to 120 psi (or slightly less) as verified by the high side gauge and then shuts off under Crio control. While this test is running your inspector will also examine the low side gauge to insure that the pressure there rises to 60 psi and no higher. Then you will be asked to disable the robot and vent the pressure at which time both gauges should return to zero.

Al,

Could you please quote the rule that requires the high side to go to 120PSI?

There are teams considering using compressors that have a max 105PSI.

[Al Skierkiewicz]

Daniel,
This is the test we have been using as part of inspections for at least the last five years. The rules state...
<R74> If pneumatic components are used on the ROBOT, the pneumatic system on the ROBOT must contain as a minimum
• Pressure gauges to display the “stored” and “working” air pressure (see Rule <R76>), the following components, connected in accordance with this section.
• A pressure relief valve, calibrated and set to release at 125psi (see Rule <R77>),
• A pressure switch, calibrated and connected to the ROBOT control system (see Rule <R78>),
• An easily visible and accessible pressure vent plug valve to manually relieve the stored pressure (see Rule <R79>).
And...
<R78> The Nason pressure switch must be connected to the high-pressure side of the pneumatic circuit (i.e. prior to the pressure regulator) to sense the “stored” pressure of the circuit. The two wires from the pressure switch must be connected directly to a digital input and ground port on the Digital Sidecar, and the cRIO-FRC must be programmed to sense the state of the switch and operate the relay module that powers the compressor to prevent over-pressuring the system.
This is tested during the powerup section of the inspection checklist. (hopefully similar to 2009 and prior)

If you are using a compressor that cannot achieve shutoff pressure, then the solution needs to be addressed by the GDC. My first question would of course be what is the max pressure that the compressor can withstand? Does the pressure relief valve protect that max pressure and how to shut off the compressor before achieving that pressure.

[Daniel_LaFleur]

Originally Posted by Al Skierkiewicz

Daniel,
This is the test we have been using as part of inspections for at least the last five years. The rules state...
<R74> If pneumatic components are used on the ROBOT, the pneumatic system on the ROBOT must contain as a minimum
• Pressure gauges to display the “stored” and “working” air pressure (see Rule <R76>), the following components, connected in accordance with this section.
• A pressure relief valve, calibrated and set to release at 125psi (see Rule <R77>),
• A pressure switch, calibrated and connected to the ROBOT control system (see Rule <R78>),
• An easily visible and accessible pressure vent plug valve to manually relieve the stored pressure (see Rule <R79>).
And...
<R78> The Nason pressure switch must be connected to the high-pressure side of the pneumatic circuit (i.e. prior to the pressure regulator) to sense the “stored” pressure of the circuit. The two wires from the pressure switch must be connected directly to a digital input and ground port on the Digital Sidecar, and the cRIO-FRC must be programmed to sense the state of the switch and operate the relay module that powers the compressor to prevent over-pressuring the system.
This is tested during the powerup section of the inspection checklist. (hopefully similar to 2009 and prior)

If you are using a compressor that cannot achieve shutoff pressure, then the solution needs to be addressed by the GDC. My first question would of course be what is the max pressure that the compressor can withstand? Does the pressure relief valve protect that max pressure and how to shut off the compressor before achieving that pressure.

Thanks for the clarification Al.

I guess this will have to be a Q&A question since the cRIO could be programmed to read the pressure switch and shut off the compressor @ 120PSI but not be able to test that programming if the compressor is not capable of 120 PSI.

[thatoneguy23]

cool, thanks for the info guys.