Adjusting (analog) servo center point
05-22-2004, 09:21 PM
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Adjusting (analog) servo center point
Has anyone messed with an analog servo pot to adjust the center point? If so, how sensitive is it? I'm wondering if it's practical, because I would like to better match servos in certain situations.
Thanks.
Thanks.
05-22-2004, 10:52 PM
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RE: Adjusting (analog) servo center point
It is not difficult to do, Just make sure you turn the pot and not the motor gear.
I find that the hardest part is putting the o-ring back into place when you take it apart.
I find that the hardest part is putting the o-ring back into place when you take it apart.
ORIGINAL: mulligan
Has anyone messed with an analog servo pot to adjust the center point? If so, how sensitive is it? I'm wondering if it's practical, because I would like to better match servos in certain situations.
Thanks.
Has anyone messed with an analog servo pot to adjust the center point? If so, how sensitive is it? I'm wondering if it's practical, because I would like to better match servos in certain situations.
Thanks.
05-23-2004, 06:22 AM
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RE: Adjusting (analog) servo center point
I understand the question and the answer, but that setup may change from arm to arm if you know what I mean.
Have you tried different arms, and/or turned them 180° if they are two sided_bob
Have you tried different arms, and/or turned them 180° if they are two sided_bob
05-23-2004, 08:50 AM
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RE: Adjusting (analog) servo center point
That is true, if you rotate the arm 180° it will change it.
If he has to use that are in that application, the only way I know is to move the pot gear.
If he has to use that are in that application, the only way I know is to move the pot gear.
ORIGINAL: bob_nj
I understand the question and the answer, but that setup may change from arm to arm if you know what I mean.
Have you tried different arms, and/or turned them 180° if they are two sided_bob
I understand the question and the answer, but that setup may change from arm to arm if you know what I mean.
Have you tried different arms, and/or turned them 180° if they are two sided_bob
05-23-2004, 09:47 AM
#5
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RE: Adjusting (analog) servo center point
If the servo has an odd number of splines on the shaft, rotating the arm 180 degrees will shift the center a bit, if even numbered it won't help. As to adjusting the servo pot, depends on the servo construction. On most you can break the pot housing free and rotate it a bit to change centering. Just make sure that you fasten it back down adequately or it will shift while in use. The older style servos actually had a screw that locked the pot in the proper position, some of the newer ones have just a friction fit or are glued in place.
05-23-2004, 11:21 AM
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RE: Adjusting (analog) servo center point
The older style servos actually had a screw that locked the pot in the proper position, some of the newer ones have just a friction fit or are glued in place.
Some use a locating tab. All you have to do is take the pot out. file the tab down a little on both sides (or you could just remove it totally) put it back in an d adjust it. Once you have it I would put a dab of silicone on it to make sure it doesn't drfit.
05-23-2004, 11:54 AM
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RE: Adjusting (analog) servo center point
Thanks, everyone. Since I know it can be done now, it's easily worth experimenting with a spare servo.
I have tried to flip arms. As Rodney says, some splines are even numbered, and even with odd-numbered splines, sometimes you just get caught in-between.
I'd just like the option of centering a servo really well... without going digital.
Thanks again.
I have tried to flip arms. As Rodney says, some splines are even numbered, and even with odd-numbered splines, sometimes you just get caught in-between.
I'd just like the option of centering a servo really well... without going digital.
Thanks again.
05-24-2004, 10:14 AM
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RE: Adjusting (analog) servo center point
You cannot blame the lack of centering all on the servo. There is some slight differences between transmitters, even between the different channels on one transmitter. Theoretically, the transmitteres are adjusted to put out 1.5millisecond neautral pulses but they are not exact, can vary 5 to 10 percent in worst case tolerance build up. I have seen one case where it was much worse than 10%. On some transmitters, you can adjust this by loosening a set screw, readjusting the pot on the stick then tightening down the setscrew again. Some are again, just friction fit to the pot shaft and you can have them slip accidently causing no end of frustration.
05-24-2004, 11:15 AM
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RE: Adjusting (analog) servo center point
ORIGINAL: Rodney
You cannot blame the lack of centering all on the servo. There is some slight differences between transmitters, even between the different channels on one transmitter. Theoretically, the transmitteres are adjusted to put out 1.5millisecond neautral pulses but they are not exact, can vary 5 to 10 percent in worst case tolerance build up. I have seen one case where it was much worse than 10%. On some transmitters, you can adjust this by loosening a set screw, readjusting the pot on the stick then tightening down the setscrew again. Some are again, just friction fit to the pot shaft and you can have them slip accidently causing no end of frustration.
You cannot blame the lack of centering all on the servo. There is some slight differences between transmitters, even between the different channels on one transmitter. Theoretically, the transmitteres are adjusted to put out 1.5millisecond neautral pulses but they are not exact, can vary 5 to 10 percent in worst case tolerance build up. I have seen one case where it was much worse than 10%. On some transmitters, you can adjust this by loosening a set screw, readjusting the pot on the stick then tightening down the setscrew again. Some are again, just friction fit to the pot shaft and you can have them slip accidently causing no end of frustration.
05-24-2004, 12:37 PM
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RE: Adjusting (analog) servo center point
My original question was based on a desire to match two servos split from the same channel. But now I guess I would want to know if Tx/Rx signals are consistent over time, even if they vary from unit to unit or channel to channel. If so, you can "match" a servo to a particular channel.
