RC Radios, Transmitters, Receivers, Servos, gyros Discussion all about rc radios, transmitters, receivers, servos, etc.

Programmer for Digital Servos

Reply

Old 08-15-2004, 09:52 PM
  #1  
Tricktrack
Senior Member
Thread Starter
My Feedback: (2)
 
Join Date: Nov 2003
Location: Columbus, NE
Posts: 261
Gallery
My Gallery
Models
My Models
Ratings
My Feedback
Default Programmer for Digital Servos

I am looking for some info on programmers for Digital servos. New to digitals and just really do not understand them much yet. Is a programmer needed, or just something extra.
Tricktrack is offline  
Reply With Quote
Old 08-16-2004, 02:41 AM
  #2  
JohnMac
 
JohnMac's Avatar
 
Join Date: Oct 2002
Location: Leeds, UNITED KINGDOM
Posts: 1,412
Gallery
My Gallery
Models
My Models
Ratings
My Feedback
Default RE: Programmer for Digital Servos

Its an extra. Digitals work straight out of the box. So far as I know only Muliplex and Hitec make prgrammable servos.
Regards,

John.
JohnMac is offline  
Reply With Quote
Old 08-16-2004, 10:01 AM
  #3  
hilleyja
Senior Member
My Feedback: (3)
 
Join Date: Jan 2002
Location: Salem, WV
Posts: 2,181
Gallery
My Gallery
Models
My Models
Ratings
My Feedback
Default RE: Programmer for Digital Servos

JohnMac is correct, the programmer is an extra, even for the Multiplex and Hitec digital servos.

I'm only familiar with the Hitec. I have a total of 19 Hitec digital servos that I use on 120+ size airplanes. I find the programmer very usefull because it allows me to initialize the servos without having to make large transmitter adjustments to subtrim and extents. It is most usefull when you need to match servos to the same control surface. My primary use in that area is split elevators. It is almost a must if you need to match multilple servos to the same control surface like dual sevos on a single airlon. Of course, both JR and Futaba do have devices that help you do that (JR Matchbox, Futaba MSA-10 Servo Synchronizer) but they will run you $70 and $60 extra and you will need one for each separate control.
hilleyja is offline  
Reply With Quote
Old 08-16-2004, 04:43 PM
  #4  
roxberrym
My Feedback: (57)
 
Join Date: Mar 2003
Location: Jackson, MI
Posts: 9
Gallery
My Gallery
Models
My Models
Ratings
My Feedback
Default RE: Programmer for Digital Servos

I am also a relative new-commer to programming digitals. Can anyone provide some specifics on what I am trying to accomplish with the programmer and what functions I should concentrate on? For example, if I reset the servo to factory specs...is that all that is necessary? Or is it desireable and/or why is it desireabole to reduce the dead band width, increase the speed, or complete other adjustments? I'm trying to figure out what I am to achieve when setting up dual servo ailerons and elevators on an Extra. Thanks.
Mike R
roxberrym is offline  
Reply With Quote
Old 08-16-2004, 09:07 PM
  #5  
hilleyja
Senior Member
My Feedback: (3)
 
Join Date: Jan 2002
Location: Salem, WV
Posts: 2,181
Gallery
My Gallery
Models
My Models
Ratings
My Feedback
Default RE: Programmer for Digital Servos

I'm a long way from considering myself an expert here and my experience is only with the Hitec programmer. I'm told you can assume the servos are linear in their motion from neutral to end-point. This makes it important to match the neutral and endpoints to the same values physically. What this means to me is that I adjust the servo lever so that it is exactly 90 degrees to the servo case and set that as the center point with the programmer. I then use the programmer dial to adjust the endpoint of the servo in one direction the the desired maximum and set the left or right endpoint on the programmer -- repeat for the other direction. This will usually get you very close. Use your TX (subtrim set to 0 and endpoints set to some equal value between 100 and 140.) Then 1st make sure the surface is at neutral by adjusting the clevis and then measure the endpoints. If the endpoints are off go back to the programmer and make minor adjustments to each endpoint according to how much they are off. It usually takes 2-3 transistions to get the the values you want. This is the way to match servos.

Now, I'm not really familiar with the deadband adjustment but can hazard a quess for its use. You can only increase the deadband, it is factory set for its minimum. If for some reason you have a control surface that has a little torque away from neutral and you find your servo constantly chattering (digital servos sound like whining) you can probably increase the deadband to the point that this chattering/whining stops.

Another adjustment is speed. Servos come from the factory set for their maximum speed. The programmer allows you to slow them down -- examples for that requirement should be easy to come up with.

Another adjustment is the direction of the servo -- you can reverse it.

The rest of the capabilities of the Hitec Servo Programmer can be used for any servo, any brand, any format. It lets you test the servo responses and in some cases allows you to "burn-in" a servo, run it for a period of time to make sure it is not going to fail. It also lets you measure the pulse width being put out by the TX for any given neutral point or any position of the TX control stick. E.G. The neutral position of a Hitec TX control stick is 1500ms. The neutral position of a Futaba TX is ~1518ms.
hilleyja is offline  
Reply With Quote
Old 08-17-2004, 02:52 AM
  #6  
JohnMac
 
JohnMac's Avatar
 
Join Date: Oct 2002
Location: Leeds, UNITED KINGDOM
Posts: 1,412
Gallery
My Gallery
Models
My Models
Ratings
My Feedback
Default RE: Programmer for Digital Servos

My experience is with the Multiplex servos and programmers. They are extremely useful servos when you need to Y lead two or more servos and get the same response from them all; two examples:
On scale gliders on the spoilers (which are notoriously non linear in operation) I set up the servo with an offset centre point to give a more linear response. When I am happy with the first one I invariably need to reverse the second servo, adjust the centre point so that both spoilers are moving the same, and then the end points to get full travel without stalling.
They were even more useful on my F-86 Sabre slats. 4 Mpx micro MC V2 servos drive these from a single channel. Due to the layout in the wing the servos had to lay one to the left, one to the right, so every second servo needed reversing. Again due to slight differences in servos and linkages the movements needed fine tuning to stop one end of the slat coming out befor the other, and again to match the travel end points. It took a little time but the results are excellent.
The Hitec programmer looks much more user friendly the either of the 2 Mpx versions (V1 & V2 sevos) but at about 4 times the price.
Regards,

John.
JohnMac is offline  
Reply With Quote

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off


Thread Tools
Search this Thread

Contact Us Archive Advertising Cookie Policy Privacy Statement Terms of Service