The part that converts one quantity (tension) into another (volts, whatever)
is the transducer. If you put a readout on it it's a meter. "Pull-Test
Load Cell" sounds like a good name.
1-1/2 tons is a large fish, so the fish scale idea is probably out. 3000
pounds sounds impressive but in 11-pound increments you're only asking for
slightly more than 8 bits of resolution. This should be doable.
Is this single-use or are you trying to make a product? If you're just want
to buy something check McMaster-Carr (
www.mcmaster.com) -- they may have
something with the resolution you want. You should also check Omega
(
www.omega.com). They tend to specialize in the "beginning industrial"
segment, their stuff is slightly more expensive than others but they hold
your hand when you go to use it, which can be very nice.
If there isn't something that exists then this is as much a problem of
mechanical design as it is electrical. You should be able to take a
compression load cell and wrap it in such a manner that tension on your
cable equals compression on the cell, then you can read it out. If you want
to start entirely from scratch you should be able to apply the load cell
idea to tension -- I see no reason why a proof ring or a strain gauge can't
work in tension as well as compression.
If you want help designing a product email me and I can round up a crew for
you & get the job done. No guarantees on hitting price/performance points
until we've looked at the problem, though.
-------------------------------------------
Tim Wescott
Wescott Design Services
http://www.wescottdesign.com
Phone: (503) 631-7815
Cell: (503) 349-8432
