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Unread 18-07-2014, 22:24
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Nyle Nyle is offline
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Re: Linear Actuators

Quote:
Originally Posted by JamesTerm View Post
So I have a question for everyone who has used the lead screw technique. How did you do a set point operation... like if you want it to go a certain distance? Did you:

1. Use an encoder?
2. Use a potentiometer?
3. Use a limit switch?
4. String potentiometer?
4. Something else?


If you used an encoder how do you ensure it remains calibrated (e.g. limit switch). I'd like to use this lead screw technique, but I haven't found reliable way to sense distance. (I have not tested the string potentiometer either).
For a while in 2013 our launcher was articulated using a lead screw (at first , we later replaced it with a piston) and we used a few magnetic reed switches (they sense the proximity of a magnet) to sense when the screw was close to either end, as well as a set-point in the middle.

If you just need to move to certain set-points, and are ok not knowing exactly where you are when between them, using switches that trigger at the important points can be both reliable and easy to set up.