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Author Topic: Servo tester...... Instructions help  (Read 3652 times)

Unsinkable 2

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Servo tester...... Instructions help
« on: February 04, 2016, 07:15:36 AM »

Hello all, I think I may have a problem with a servo so I decided to have a look for a servo tester, they are a cheap electronic gadget that helps you to, well, test servos I suppose.........


Not being very good with such matters I decided to read what it does and how to use it before buying, but unfortunately that left me more confused than before.


Here is a copy of what was written

'Can be synchronized output control 4 servos and used to compare the performance steering gear control of the steering servo output signal can be accurate to 2us (1 milliseconds = 1000 microseconds), you can test the steering gear is able to respond to subtle changes With PPM signal test function in the display, the input PPM signal changes while the input the PPM signal synchronization output to the servo Energized automatically enter manual mode (Manual) 20us 50H analog servo signal cycle, frequency 50Hz, rotary potentiometers to decrease or increase the width of the output pulse.'


Does that make sense to anyone? I was expecting you plug in the servo and the machine has a green or red light for problem or no problem...... Or an advanced version that says full movement took half a second and then you compare that time with what it says it should be.

My problem is that the servo alone seems to work fine but once plugged in other things seem to start going 'funny' I've checked the mixing on my radio and they are all off.

Any ideas?.....   U2
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Tug Fanatic

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Re: Servo tester...... Instructions help
« Reply #1 on: February 04, 2016, 07:51:54 AM »

That is, I think, Chinese English. Unfortunately it is not the same as English spoken anywhere else in the world.

I will have a go but if anyone else has a better guess I defer to them. It sounds like a pretty standard servo tester.

It sounds like that it will connect to 1-4 servos or speed controllers and that there is a control knob that lets you move the servos in small increments to test them across their range of movement. I think it also has an automatic mode (most do) that runs the servo across their full range of movement repeatedly. This is very useful for testing a servo or speed controller that you are not sure is working properly. For model aircraft where good servos are critical I find it invaluable. Look for your servos moving reliably and smoothly and without noise that suggests a problem for a good few minutes. Also look at your linkages for free movement, no jerkiness, proper movement of rudder etc etc. It is very useful if you can set the end limits of movement so that you do not try & ask the servo or the thing that it controls to go somewhere beyond where it wants to go.

There are no green or red lights on servo testers but rather they let you set up and test your servos without needing to have the transmitter/ receiver connected. Think of them as a transmitter/ receiver substitute with the advantage of automatically cycling the servos if you so wish. 

I have this one which I find works well & does everything that I need.

http://www.hobbyking.com/hobbyking/store/__31773__turnigy_760lv_hv_dual_pulse_width_selectable_servo_tester_uk_warehouse_.html

What do you mean when you say "other things seem to start going funny". What other "things" & what does "funny" involve?

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nivapilot

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Re: Servo tester...... Instructions help
« Reply #2 on: February 04, 2016, 08:15:42 AM »

Just as Tug Fanatic says.
a battery or BEC voltage needs to be applied to the input end, and a servo to be checked into the output end, you can test up to four simultaneously.
once connected you should? be able to switch between auto test and manual test, the control knob, once turned should actuate the servo.
I see no way another component should act up.......unless the other components are getting voltage from the servo?? and b not battery supply?
Again lets know what's happening.

I went for the cheaper version....still works well though, 2 ish on fleabay.
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Brian60

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Re: Servo tester...... Instructions help
« Reply #3 on: February 04, 2016, 08:36:28 AM »

Must be something in the water! I had a similar problem with servos last week.


Here's a tester that Richard D suggested, 10 day supply from the land back east though.....

http://www.banggood.com/Wholesale-EK2-0907-Updated-Version-Servo-Tester-Server-Electronic-Speed-Controller-p-66240.html

malcolmfrary

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Re: Servo tester...... Instructions help
« Reply #4 on: February 04, 2016, 08:46:46 AM »

Quote
'Can be synchronized output control 4 servos and used to compare the performance steering gear control of the steering servo output signal can be accurate to 2us (1 milliseconds = 1000 microseconds), you can test the steering gear is able to respond to subtle changes With PPM signal test function in the display, the input PPM signal changes while the input the PPM signal synchronization output to the servo Energized automatically enter manual mode (Manual) 20us 50H analog servo signal cycle, frequency 50Hz, rotary potentiometers to decrease or increase the width of the output pulse.'
Can be synchronized output = "It has several outputs which wok together so you can see that a bunch of servos all work the same"
The rest of it  just says that it gives standard signals to control the servo in small steps (probably about 250 steps for the travel that we normally expect) under control of the knob.
In Star Trek, when the plot gets a bit thinner than usual, they need to do something that is previously un-doable.  To achieve this, they break into "techno=babble".  Much the same happens with PRC vendors when they write their specifications since the makers probably don't have English, and the translators probably don't speak technical, but do have a thesaurus. Possibly the one use by Monty Python.
I got the one used by Nivapilot - works great, it just needs a bit of thinking as to which way round the servos plug in.
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craggle

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Re: Servo tester...... Instructions help
« Reply #5 on: February 04, 2016, 08:58:05 AM »

Not sure I need one of these at the minute but just looked on ebay and there is the blue unit posted above for sale with free delivery from Hong Kong for only 99p
At that price I'd feel a fool if I didn't order one....


Craig.
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nivapilot

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Re: Servo tester...... Instructions help
« Reply #6 on: February 04, 2016, 09:46:25 AM »

Not sure I need one of these at the minute but just looked on ebay and there is the blue unit posted above for sale with free delivery from Hong Kong for only 99p
At that price I'd feel a fool if I didn't order one....


Craig.

I got "stung" then at 1:10???
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Tug Fanatic

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Re: Servo tester...... Instructions help
« Reply #7 on: February 04, 2016, 10:01:40 AM »

One of the reasons that I chose mine was that you could connect a three cell LiPo (11.1v) or 12v lead acid battery as the power source as I do not use a receiver battery in any of my models. At the time that I purchased it the cheaper testers had a much more restricted range of acceptable input voltages.

Does the Bangood example that is being suggested cope with anything other than a 4.8v receiver pack?
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jarvo

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Re: Servo tester...... Instructions help
« Reply #8 on: February 04, 2016, 10:05:17 AM »

I bought one and it is great for isolating a suspect servo, invest you wont be sorry


Mark
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Re: Servo tester...... Instructions help
« Reply #9 on: February 04, 2016, 10:29:47 AM »

Guys you are collectively phenomenal  O0


I have to go to work now but will reveal all what's been happening after re plugging and watching EXACTLY what happens as soon as I get a chance (probably weekend).......


In brief sail winch servo absolutely fine on its own but when plugged into the boats reciever I get problems with the rudder!     Like I said I will re check and report back with FACTS...... Thanks for all your help


Malcolm good Star Trek reference, made me laugh........ {-)      U2
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sparkey

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Re: Servo tester...... Instructions help
« Reply #10 on: February 04, 2016, 01:22:14 PM »

Check the battery,sail winch servo will take more current than normal servo and this results in volt drop which will make the servo behave strangely,try with another battery.....Ray
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inertia

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Re: Servo tester...... Instructions help
« Reply #11 on: February 04, 2016, 01:41:30 PM »

Or run the sail-winch from its own battery pack.
DM
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Netleyned

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Re: Servo tester...... Instructions help
« Reply #12 on: February 04, 2016, 02:07:03 PM »

All my yachts are run on 6v NiMH packs so that any volt drop due to the sail
winch effort will not drop enough to affect the Rx and Rudder Servo.
Apart , that is, from my Marblehead which runs from a 7.2V stick for the
Whirlwind winch which has a built in BEC for the Rx and Rudder.
I have seen many strange happenings with yachts run on 4.8V as the sailwinch/servo
when working hard drags the Volts down to an unacceptable level.


Ned
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Tug Fanatic

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Re: Servo tester...... Instructions help
« Reply #13 on: February 04, 2016, 02:13:41 PM »

I am ssuming by "problem" you mean that it works but with problems like (glitching) dithering.

Have you got a faulty motor in one of the servos that is causing interference that is causing glitching? I have never heard of it happening but there is not an obvious answer.

Space the servos as far as the leads make possible - if necessary not in the model - from the aerial & receiver. Does it still glitch?
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malcolmfrary

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Re: Servo tester...... Instructions help
« Reply #14 on: February 05, 2016, 09:17:23 AM »

A sail arm servo with its high power demands makes a great tester for power supplies - batteries and all of the associated wiring.  Under load, they can cause the supply voltage to the rest of the system to jitter a bit.  Because of the way that the servo internal electronics work, this can also have an effect on other servos running on the same power source.  Work the sail servo, rudder jitters, check out the battery, wiring and switch.
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inertia

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Re: Servo tester...... Instructions help
« Reply #15 on: February 05, 2016, 10:22:41 AM »

Some receivers and other electronic add-ons are not happy at much above 5.5v, whereas a fully-charged 5-cell NiMH pack can put out as much as 7.0v initially. This circuit allows you to run the sail winch from a high-voltage, high-capacity NiMH pack without putting any drain on the separate 4-cell receiver battery.
DM
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Unsinkable 2

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Re: Servo tester...... Instructions help
« Reply #16 on: February 05, 2016, 08:23:51 PM »

Some very interesting things on here.


Inertia, thanks for the diagram I'll bear that in mind for future reference. :-))


As for my 'problem' well, I still haven't had a chance to sit down with my boat and notepad. (Like I said, weekend) ...... But I can say that I have a lipo battery 11.1v (12.6v fully charged) which powers my ESC (throttle and therefore reciever) and rudder, as well as the chimney servo and brushed ESC for the smoke unit (with red wire cut ).


I have a separate 12v battery which powers my sound machine and smoke machine.


Things only seem to go 'funny' once I plug my winch servos in. It's fine without it plugged in.


As a mechanically minded person I see the problem can only be the servo (fine without not fine with) but electrickery is strange stuff and testing the servo on its own with the same reciever in the same channel and with the same radio shows the servo to work fine!       That's why I thought I would buy a servo tester in the hope that you plug it in and a green or red light says good or bad........U2
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Tug Fanatic

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Re: Servo tester...... Instructions help
« Reply #17 on: February 06, 2016, 09:03:14 AM »

I am intrigued. What is the model that has both a smoke unit and a sail winch?

Do you have the correct required voltage going to everything in the system? It sounds like there might be a range of voltages required for that lot.

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malcolmfrary

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Re: Servo tester...... Instructions help
« Reply #18 on: February 06, 2016, 10:36:21 AM »


As for my 'problem' well, I still haven't had a chance to sit down with my boat and notepad. (Like I said, weekend) ...... But I can say that I have a lipo battery 11.1v (12.6v fully charged) which powers my ESC (throttle and therefore reciever) and rudder, as well as the chimney servo and brushed ESC for the smoke unit (with red wire cut ).

The brushed ESC for the smoke unit will supply its own 5 volts via its own BEC, hence the need to disconnect the red wire to stop it joining in.
The BEC in the main ESC seems to be powering everything else - it might not have quite enough output to drive itself, the receiver, the rudder and the chimney servo.
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jarvo

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Re: Servo tester...... Instructions help
« Reply #19 on: February 06, 2016, 11:52:54 AM »

UU2, from your description your sail winch is taking its power from the BEC, this normaly only supplies 1amp, the sail winch will take far more than that under load, my thought is that a seperate battery supply for the winch is required


Mark
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richald

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Re: Servo tester...... Instructions help
« Reply #20 on: February 06, 2016, 07:51:55 PM »

If you don't have enough 'grunt' from the BEC in your main ESC can I suggest you have a
look at the following ....

http://www.banggood.com/Hobbywing-3A-UBEC-5V-6V-Switch-Mode-BEC-For-RC-Models-p-915037.html

I am considering upping the voltage from the battery pack in one of my yachts and then fitting
one of these - the sailarm servo seems to get a bit 'lazy' on the usual 4 x AA cell battery pack.
With the UBEC set to 6 volts (even digital) servos seem to be much more 'snappy' and they seem to hold better.

Richard
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Unsinkable 2

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Re: Servo tester...... Instructions help
« Reply #21 on: February 07, 2016, 07:34:04 PM »

I seem to be getting closer now thanks to you guys......


It seems that my sail winch is taking a little more than its fair share of electrickery. Lena runs quite happily with the motor and chimney chugging away ........ The weight of Lena is far from scale and the sails are inadequate for the weight SO the boom stays in the same position so as to not knock into the chimney which is almost constantly up and the sail winch is redundant (for now)


So thanks for all your help. If I decide to start using the boom again I shall do as Inertia showed in the diagram. PROBLEM SOLVED :-))


Tug Fanatic..... See Lena page 4 at the bottom all will become clear.........








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