I purchased a servo programmer that works with pc software in order to test and/or set various parameters on certain Hitec digital servos I now own. I did so because it was only a little over $25 and I thought it might come in handy someday.

Anyway, I downloaded the software, connected the programmer to my pc via a usb cable, and to a 4.8volt pack and one of the digital servos, and tried it out.

I first ran a test sweep and then a test automatic step from end to end. The programming features are travel speed, direction, end points and center points, failsafe on or off, all things I can do with my radio. It can also do a few things the radio can't, or I don't think so anyway, for example, resetting to factory specs, and dead bandwith setting.

The instructions say the programmer can be used to burn in a servo and to check for broken gears. How are these done? What is burning in a servo and how useful is it? How would one check for broken gears beyond just listening and watching for clicks/gaps in the rotation?

Thanks.

"Burning in" (which in my opinion is pointless) is just hooking it up and putting in test mode and letting it run back and forth for a while.

To check for broken gears put your finger on it and give it light resistance while it's sweeping back and forth. It will feel gritty or the arm will skip if there's a torn up gear or gears.

Burning in a new servo? Now there's a novel idea.

No, you don't need to do that.

Those devices are great for centering servos and finding the servo movement range, but burning in a servo?

CGr.

Maybe it should be called "testing" a new servo. I guessany possible earlyfailure mode would only show up when it is subjected to vibration and flight stress variables (unfortunately this is only practical in the actual aircraft!). Simply running it back an forth seems more like a simple pass/fail test. I like the proposal for checking gear damage before deployment, though.

Art

This thing is probably a gizmo that minimum wage "techs" use to QC servos with before packaging. A guy from the marketing dept. saw it on his way through the plant, a light went off in his head and it has now become another one of those "must have" gizmos for the public.

The "Burning In" goes back to the early days and not so early days of electronics when electronic devices had "VALVES" (Those glass tube things) that glowed an orange colour from the heating element that is inside it.

Cheers

...or it could be a pretty cool tool to set points, throws, and other things on servos, especially for people without the most expensive radios. This thing works fantastic for things like dual elevator servos, or if you don't have individual servo endpoint adjustment on certain channels of your radio.

My hypothesis is that 'burning in' is a layman's term for testing the servo through it's full range of motion to ensure smooth, lubricated travel.

Servos and batteries/switches are weak points in our control systems.

In electronics you have the bathtub curve of failures. A short burn-in period is often used to catch infant mortality. For a servo, the electronics might be well served by operating them for 24-48 hours, but the motors and pots would not helped by such a lengthy test period if moving over that time period.

A few minutes of operation, listening to the servo and slightly loading it as suggested by Andy in post 2 will tell you all you need to know.

However for the truly paranoid, you can cool the radio to freezing and test it's function, then heat the radio to about 130 degrees and test. The expansion and contraction of PC boards and solder joints will uncover problems that may exist. Also test against vibration by placing it on a jig saw and buzz at different speeds.

Then, before the first flight of the day, range check and check batteries before each flight under a fixed load.

For bigger airplanes, use dual elevator and dual aileron servos. This will save the bacon 90% of the time.

Most crashes are pilot error, so ...

Measuring the control surfaces' deflection with an angle finder or more simply just a ruler has worked well enough for a long time. Plugging the servo into the RX it is intended to be driven by is the most relevant way to test any servo.
Throws should be set mechanically at the servo arm and control horn, there is no magic tool that will do that for you other than a screwdriver.

It's a bit more than that.
Everything electronic has the possibility of failure. The actual chance of a failure in any period is "the probability of failure". When the period is a standard hour, then this probability of failure is expressed as a figure called MTBF or "Mean Time Between Failure" for repairable items and Mean Time to Failure for non-repairable items and is quite often in the millions of hours for static electronic units.
If this probability of failure is plotted against service life, there's usually an initial high probability for a time, known as the "infant mortality period"; then the probability of failure settles to a lower (hopefully much lower) value; then as the unit gets to the end of its life, the probability rises again. Electromechanical devices have distinct wear-out mechanisms, whereas "pure" electronic assemblies tend to wear out by odd things like moisture ingress into the packages, doping impurities migrating etc. These later mechanisms are mitigated by higher component quality and assembly techniques such as conformal coating.
"Burning-In" refers to a method of quality screening where the product is subjected to a brief, high stress, operating regime that simulates the actual service time relating to the infant mortality period. The idea is to weed out poor components and badly assembled units. The high stress is usually an elevated operating temperature, hence "burning-in". An incorrect burning in however can just serve to stress the units to destruction!

I bought a gizmo called TXServo a couple of years back. It connects to a PC via USB and comes with a program that allows you to run various "scenarios". I never referred to it as burning in a servo, but I have used it to center the servos.

The device has four slots that look pretty much like an RX servo plug-in area and I can "exercise" four servos at once.

As I said, I've used it to center servos prior to doing various connections and adjustments to the linkage.

The below is a screen capture from their web page.

CGr.

Even if you get two of the exact same servo, they are not guaranteed to move exactly the same amount. You can set up your surfaces mechanically to have identical throws, but if the servos are not perfectly matched you will still have uneven surface throws.

I wouldn't call this thing a 'must have' but it is a cool extra gadget to have around for those of us that like gadgets

I think it is nothing a person reading the "Beginners" forum (as a beginner) needs to be concerned with.

People who compete, and other advanced pilots, may or may not find it useful.

I myself am a beginner, just started flying last season anyway, and I think this thing has some useful functions, even for a beginner. Not a requirement but neither is something as basic as a starter over a chicken stick. It's good to be aware of anyway, in my opinion.

You need to understand linearity and monotonicity of devices to understand the problems in matching servos. A simple baseline article is here, but if you become an engineer, you might spend much more time grappling with the subject.

http://www.analogzone.com/nett1108.pdf

That's a pretty cool article. Definitely worth (for me) spending some more time reading. So far I've only looked at linear systems.


I set up my Yak very carefully with respect to the control system. The aileron control arms are pretty much identical, and center points and one of the end points were perfect. However, one aileron would deflect slightly more than the other, in only one direction. I definitely am one to try a mechanical fix before turning to electronic 'crutches', however I couldn't seem to get all points matched up. The result was a plane that yawed substantially with right aileron input. My radio didn't have the ability to independently set dual aileron endpoints, so I got this servo programmer, and the problem was quickly solved. These were two brand new, identical servos (HiTec 7000 series).

Anyway the OP is not talking about programming servos (although he does mention that this unit is capable of doing so [which requires compatible servos]). There are other good functions that this unit does that can be beneficial to anyone, including beginners (in my opinion). I appreciate having a tool to check and center servos before installation, without the need of using my complete radio system. It is a good way to check those pre-owned servos that many of us come across.

Seems like the original questions were answered: check for broken gears by listening and feeling the servo horn during travel, applying light resistance if necessary. "Burning In" is a bit of slang (in this case) for checking the range and functionality of the servo.

Do you realize that when you swap your servos that were tested outside the plane by this gizmo, then plug those servos into the plane's RX.... the RX in the plane could assign it's own different centers and servo behavior? I've swapped enough RXs in elevon equipped planes to know that this can happen.

And I thought it was only Duck Hunters that would go out and buy any new Gadgets for his sport. I have asked a number of IMAC pilots about servo programmers and there statement has pretty much been SUB TRIM!! All of them were running some type of match box system that would dial in there ganged servos though. If you don't have a radio that is able to do the servo programming you need then you sure don't need those servos. I'm sorry if I sound like I'm laughing at the gimmick buyers but I am!! I was a Duck Hunter for too many years and it took time to rediscover the basics, they work and leave you with more money in your pockets and less crap on your back.

That's a good point, and no, I didn't realize that at the time. However my endpoints are now all spot-on and the plane flies beautifully.

Hmm, interesting phenomina.

Receivers don't assign different centers, but they do have to work with a signal of very low bandwidth due to the narrowbanding of transmitters some years back. As a result, the slope of the signal sent by the transmitter when turning on and off was decreased, and the internal circuitry of the receiver that determines where the on and off edges of the signal exists in time are very depended on the filters inside the receiver. Thus servos could center different with different receivers. Even with receivers of the same make and model could experience this.

Thanks for pointing that observation out CP.

Capp I bought and used the same programmer. I set up my Yak with the Hitec programmable 7955 servo's. Let's you set Dead band, servo speed, fail safe, change rotation and overload protection for the digital servo's. Worked great for me. Good luck with the new plane.