pjr99
Heliman
Location: Boca Raton, Florida
| Just a clarification, I think the only PCM Rx that requires the buffer is the Futaba R149DP.
This Rx samples the channels in paris....1 and 2, 2 and 3, etc. The Co-Pilot cannot handle this. The buffer delays one of the channels which allows the Co-Pilot to function properly.
Please correct me if I'm wrong.
Just found the explanation on FMADirrect's website:
What is buffering and when and why do you need it?
P/N 505SB does that job. Some servos, particularly coreless motor servos of all makes are powerful and quick because the amplifiers in them are tuned to high performance and they have a coreless motor. As a result, when two are hooked in parallel, they may (But not always) interact to have a lot of jitter. This interaction is caused by the following: The control pulse going to the servos is nominally square and of some 4.2 or so volts amplitude. In actuality, the rise and fall of the pulse is sloped by the switching time of the circuit in the decoder. When a coreless servo starts to move, it draws heavy current momentarily. The battery voltage drops ever so slightly as that happens and the control pulse shifts up and down with the DC voltage. As it does, the servo perceives a change in width and starts to move and the process iterates with one servo moving, then the other feeding off that and so forth. The buffer acts to keep the control pulse amplitude where it is supposed to be and almost always stops the jittering. If you are making a set-up and jittering occurs, then you should try a buffer. If they don’t jitter, don’t worry about it; you don’t need a buffer. The longer the servo extension is, the more likely that jitter will occur because of voltage drop in the long extension.
Hope this clears it up!!!!!!!!!!!!!!!!
Phil R |
