View Full Version : How to mount rotary encoder
Logan Williams
06-01-2009, 21:43
How do you mount the rotary encoder to read the speed of the gearbox output? I can't find any guides on usfirst.org, and it doesn't seem obvious (then again, it took me an hour to figure out how to use the Wago tool...)
Any help would be appreciated.
Thanks,
Logan Williams
I'll assume you are using the toughboxes. In that case, I have an answer.
You need to either buy or make an encoder mount. AM sells them (http://search.store.yahoo.net/cgi-bin/nsearch?catalog=yhst-33833170891817&query=encoder&searchsubmit=Go&vwcatalog=yhst-33833170891817&.autodone=http://andymark.biz/amshifters.html), as well as the encoders.
On the tough box, under the motor to the side, there is an extension from the output shaft. There are two holes on the sides of that, this is where you mount the mount plate to. Take a look at the mount and you should get an idea. Be careful with the spinning pattern piece (name?), as if you're not careful you can scrape the pattern right off. On an unrelated note, anyone got an extra encoder plate?
But making your own is simple, making one took me a few hours, but only because I didn't have a small enough drill bit (1/16 I think) to drill the holes for the encoder screws. I ended up swapping the bolts out for slightly larger ones and putting a bolt on the other side.
It's a hack, but that's the way we work on 1244:D.
waialua359
06-01-2009, 23:46
If AndyMark doesnt have the mounting kit you need for what you are using,
you need to fabricate your own which isn't trivial without the right tooling and expertise.
What transmission are you using? Even with the supershifters, we had to make modifications as we had some issues with a couple of them on our current practice bot.
Logan Williams
07-01-2009, 18:45
We're using the kitbot chassis with the toughboxes.
Thanks for the advice, I'll look into it.
The andymark encoder mount also requires some modifications to fit on the toughbox if i recall.
I think Beach Bots uses surgical tubing that is zip tied to the output shaft and encoder shaft. That way if it isn't lined up perfectly, the encoder doesn't get ruined.
Ryan
guitargoddsjm
09-01-2009, 20:29
What's the distance between the center of the two holes on the mount?
What's the distance between the center of the two holes on the mount?
OK, I know those adapter plates were only $3, but they cause at least $50 of grief each.
First the plate hits the motor so you need to shave it, then the two holes that mount the encoder itself are just a bit off, so you end up using a LARGE amount of force to mount a fragile optical encoder circuit. Basically none of the critical dimensions are up to par.
JMHO
Based on my FTC experiences, the wires for the encoder (on the cable) are also extremely fragile. So mount and protect them well.
bluegrasscoder
12-01-2009, 15:39
How do you terminate the wires coming from the encoder? They are unterminated in the kit. Is there some sort of PWM female connector kit that is available?
Also, where can we get the spec sheet for the encoder, I couldn't find it on the competition manual.
Alan
bluegrasscoder
12-01-2009, 16:05
ok, so I'll partially answer my own question. I found the spec sheet here:
http://www.usdigital.com/products/encoders/incremental/rotary/kit/e4p
this is all based on the AEDR, spec sheet here:
http://www.usdigital.com/products/aedr/
So, I get "what" it is, so how do I use it? It's got two channels of output which allow you to tell if you are going clockwise or counterclockwise by comparing the outputs. Can you do this on the cRIO or do you need something else to do the processing? Do you have to make your own splitter cable for this?
Thanks in advance.
Alan
bluegrasscoder
12-01-2009, 16:18
Sorry, I'm an idiot -
http://www.chiefdelphi.com/forums/showthread.php?t=71559
This thread shows how to hook things up.
Alan
AdamHeard
12-01-2009, 16:25
I think Beach Bots uses surgical tubing that is zip tied to the output shaft and encoder shaft. That way if it isn't lined up perfectly, the encoder doesn't get ruined.
Ryan
While not the same type of encoder that is mentioned here, this method is AWESOME. I've seen them (Well, they technically use POTS) be literally 30 degrees out of alignment, I'm not talking parallel shafts that weren't concentric, I mean shafts pointing different directions. They still worked.
That surgical tubing trick sounds awesome!
By the way, if anyone a Drawing with dimensions in order to make a custom mounting plate, just contact me.
thanks, Vivek
dnklat90
12-01-2009, 20:00
That surgical tubing trick sounds awesome!
By the way, if anyone a Drawing with dimensions in order to make a custom mounting plate, just contact me.
thanks, Vivek
Are you looking for the drawings or is it that you are giving the drawings away?
Thanks, Dan
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