Quote:
Originally Posted by mikets
Okay, I am convinced it's not worth doing at the competition. However, in the spirit of learning the intention behind the rules, I would still like to understand why. I understand it's about safety. But would somebody tell me why is my proposed setup not equivalent to the onboard setup? It has the same model pressure switch that will cut off compressor power. It's using the same compressor model and spike as the onboard system. The only difference is the missing cRIO. Regarding the Emergency stop feature, there is a master power switch. We can using a giant red button for it. Again, I will not do this for the competition but at the shop when we are building the robot, there is always a need for the build team to test the pneumatic system while the electronics is being worked on in parallel. We have a modular design so each subsystem can be built and tested separately. This setup will benefit that scenario. The students have been just powering an external compressor with a battery and I always don't like it. If I understand the safety concern, we will be able to build a safe testing setup.
We have many test setup in our shop to make life easier for the build team. For example, we have a PWM generator feeding a Talon so we can test motors without the cRIO. So the pneumatic test setup is equivalent to that.
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OK. I'll take this one:
1> Are the 2 setups equivalent? No they are not ... then next few answers will demonstrate why.
2> Same model pressure switch --- the pressure switches are set to 120PSI. There is no telling (IE Proof) that the offboard pressure switch is set to the same setpoint as the onboard one. Should it not be set, the pressure could reach almost 150PSI
3> The wiring on the pressure switch is rated for less than 3 amps. The compressor runs at ~ 8 amps with a startup over 20 amps. This alone should suggest you should not do this.
When it comes to pneumatics, I'll err on the side of caution every time (and I've worked with it for ~15 years).