Ultrasonics work ok if the surface is relatively flat you are aiming at (like liquid level). Otherwise they are iffy.
Another idea; Put a reflector in the grit tank on an angle so the grit falls off the reflector. Then use a standard light sensor aimed at the reflector in the tank. When it is covered with grit - the reflector is blocked. When the sand falls off the reflector the sensor sees the reflector and you can add more sand. I had to do something similar to measure the height of a dirt pile (a small one) for a farm machine. An ultrasonic didn't work for that application. I'd run the input to a unused Mesa 24 volt input and put some logic into Classic Ladder for a couple of timers to condition the input with time on and time off delays so you don't short cycle the grit loader. Or just tie it in via hal if no timers are required. Dave On 3/21/2015 12:24 PM, jrmitchellj . wrote: > How about an ultrasonic range finder to watch how full the small hopper is? > > > Ray > > --J. Ray Mitchell Jr. > jrmitche...@gmail.com > (818)324-7573 > > > The things we admire in men, kindness and generosity, openness, honesty, > understanding and feeling are the concomitants of failure in our system. > And those traits we detest, sharpness, greed, acquisitiveness, meanness, > egotism and self-interest are the traits of success. And while men admire > the quality of the first they love the produce of the second. > -John Steinbeck, novelist, Nobel laureate (1902-1968) > > > On Sat, Mar 21, 2015 at 9:49 AM, Jon Elson <el...@pico-systems.com> wrote: > >> On 03/21/2015 09:22 AM, Viesturs Lācis wrote: >>> Hello! >>> >>> My customer acquired different abrasive hopper system for their >>> waterjet and now they want me to implement some controls over it. >>> I managed to do that, but the problem is that it can not be left in >>> "on" state for extended time as it causes the abrasive overfill the >>> small tank on abrasive regulator unit. >>> There are no sensors or anything I could use, so currently my only >>> idea is to turn it on and off on timely basis. >>> >>> >> There are long-range optical sensors that are used for this >> exact purpose. When the hopper is full, it blocks the light >> and shuts off the filling. These either have one unit and >> need a mirror on the far side, or they have two units, one >> sends the beam, the other senses it. We even have stuff like >> this on our electric garage doors to stop them when someone >> is under the door, so it is not real high-tech stuff. >> >> But, you can get modular electronic timers for general >> industrial control purposes. Some have dials, others have >> screwdriver slot adjustments or switches to set the time. >> >> Jon >> >> >> ------------------------------------------------------------------------------ >> Dive into the World of Parallel Programming The Go Parallel Website, >> sponsored >> by Intel and developed in partnership with Slashdot Media, is your hub for >> all >> things parallel software development, from weekly thought leadership blogs >> to >> news, videos, case studies, tutorials and more. Take a look and join the >> conversation now. http://goparallel.sourceforge.net/ >> _______________________________________________ >> Emc-users mailing list >> Emc-users@lists.sourceforge.net >> https://lists.sourceforge.net/lists/listinfo/emc-users >> > ------------------------------------------------------------------------------ > Dive into the World of Parallel Programming The Go Parallel Website, sponsored > by Intel and developed in partnership with Slashdot Media, is your hub for all > things parallel software development, from weekly thought leadership blogs to > news, videos, case studies, tutorials and more. Take a look and join the > conversation now. http://goparallel.sourceforge.net/ > _______________________________________________ > Emc-users mailing list > Emc-users@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/emc-users --- This email has been checked for viruses by Avast antivirus software. http://www.avast.com ------------------------------------------------------------------------------ Dive into the World of Parallel Programming The Go Parallel Website, sponsored by Intel and developed in partnership with Slashdot Media, is your hub for all things parallel software development, from weekly thought leadership blogs to news, videos, case studies, tutorials and more. Take a look and join the conversation now. http://goparallel.sourceforge.net/ _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
