Adjusting Compressor Settings

Hello, all.

Is it possible to adjust the pressure at which the pressure switch turns the compressor back on? This is the first time I’ve dealt with pneumatics on a robot, but my engineer says that it’s preset to 90, and you can’t change it (however, he wants it changed). Is the adjustment made in labview, or is it a physical thing? Does anyone know how?


Benjamin Shields

The pressure switch is to some degree adjustable. And you are correct, by rule you cannot break the seal & adjust it. There was a lot of discussion as to what was allowed under 2014 rules. This year’s rules is very specific. The legal pressure switch should shut off at about 115 psi, rising. It should turn back on at 105 or so. If yours does not do this, try a different pressure gauge. If it really shutting off at 90 PSI you should get another switch or send that one to Nason to be calibrated.

The switch drives a digital input, either to the PCM or the RoboRIO. If in the PCM, the PCM controls the compressor. If to the RoboRIO, you would have to program it, but still it should turn off & on by switch, not by speculation of the programer.

So, in essence, I’m not able to change either end?

Thanks anyway.

Yes, that’s correct. The sensor has 2 states - true and false. They cannot be adjusted.

But you can replace it with one that is properly calibrated.

Well, I looked into that, but unfortunately R68 in the Robot Rules prohibits using any other pressure switch besides the Nason pressure switch, P/N SM-2B-115R/443.

The 115R in the part number means it should switch off at 115 PSI rising. If yours is switching off at 90 PSI rising, then it is out of spec. If it is new, it should be returned to be fixed. The other possibllility is your pressure gauge is reading low and the switch is working correctly.

Hmm. That could be the root of this entire problem. I’ll switch out our gauge tomorrow and see if that solves the issue. Thanks!