Is it illegal to use take a storage tank and reserve it using one way connectors?? Basically being able to charge the whole system by using the pump, but letting only one piston run off a storage tank.
Yes, as long as all of the components meet the rest of the rules. Each tank will require a separate 125 psi gauge (high side), reducer, and 60 psi gauge (low side).
Is that a yes, they are illegal to use, or a yes, your can as long as your follow the rules?
of course you can hold air
Yes you can do this. However for each tank that is not within 1 system (meaning if you have them set so that the compressor doesn’t fill them in series or parallel) then you need to have a PSI gauge on the tank that is not within the system.
If the devices you intend to use are on the allowable list of pnuematic parts and you can fulfill the other aspects of robot rules (i.e. releasing the pressure through the supplied valve) and if your part can be followed through the flowchart, then it is likely OK. If you are planning something different, you should post the question on the Q&A. Better safe than sorry later.