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JR Servo Pulse Center Point ???????

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Old 01-27-2005, 10:39 AM
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famousdave
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Default JR Servo Pulse Center Point ???????

After about an hour of searching I have given up... does anyone know what the stock center point is on a JR 10X radio in microseconds... I think it is supposed to be 1500 but my servos do not center when I program that center point so that is telling me it must be something else...

I found a hundred threads on Futaba but not one on JR...

The end point numbers would help too!

Anyone??
DP
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Old 01-27-2005, 10:53 AM
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Rodney
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Default RE: JR Servo Pulse Center Point ???????

There may be some minor variations but every modern brand of radio I have checked has a 1.5 millisecond center with a plus or minus .5 millisecond excursion for 100% throw. If you have a scope, it is easy to check, just monitor the signal lead to the servo relative to ground at your receiver.
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Old 01-27-2005, 11:03 AM
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Default RE: JR Servo Pulse Center Point ???????

I was looking at the manual yesterday and just happened to remember the servo pulse is listed in the specs from the first few pages. Here it is:


-J120FS
Encoder . . . . . . . . . . . . . . . . 10 Channel Computer System
RF Module. . . . . . . . . . . . . . 50/53/72 MHz
Modulation . . . . . . . . . . . . . PCM (S&Z) or PPM
Output Power. . . . . . . . . . . . Approximately 750 mw
Current Drain. . . . . . . . . . . . 200 mA (70 mA w/DSC)
Power Source. . . . . . . . . . . . 1.2V x 8 NiCad (9.6V) 1100mAh
Output Pulse (in microseconds) . . . 1000-2000 (1500 neutral)
2.2 Transmitter
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Old 01-27-2005, 12:05 PM
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Default RE: JR Servo Pulse Center Point ???????

Thanks guys... I assumed it was 1500, but I needed to see it !

I think I have a servo arm / hitec programming issue I need to resolve.. I'll post it on the Hitec Board!
Thanks!

DP
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Old 01-27-2005, 12:11 PM
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bentgear
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Default RE: JR Servo Pulse Center Point ???????

DP, if you have the programmer just plug it into the receiver and read the pulse rate. My JR transmitters neutral at 1500 +/- 1.

Ed M.
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Old 01-27-2005, 01:06 PM
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Default RE: JR Servo Pulse Center Point ???????

The JR pulse is centre +/- 0.4ms, not 0.5ms, so its standard range is 1.1 to 1.9ms at 100% travel. If you turn the Tx travels up to the max 150% you get +/-0.6ms, i.e 0.9ms to 2.1ms max travel.
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Old 01-27-2005, 01:46 PM
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Default RE: JR Servo Pulse Center Point ???????

wouldn't it be great if we could program our radios directly in milliseconds instead of those irrelevant percentages?



dave
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Old 01-28-2005, 09:29 AM
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Default RE: JR Servo Pulse Center Point ???????

Yes !
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Old 01-29-2005, 12:50 AM
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Default RE: JR Servo Pulse Center Point ???????

ORIGINAL: bentgear

DP, if you have the programmer just plug it into the receiver and read the pulse rate. My JR transmitters neutral at 1500 +/- 1.

Ed M.
That's what I did. My Futaba 6EXA and 9CAP both read 1521 at center. The endpoints don't match though, the 9CAP goes out about +/-75 more than the 6EXA.

Futaba6EXA
----------------
2021
1521
1021

Futaba 9CAP Super
------------------------
2096
1521
946

Hitech
-------------
2100
1500
900
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Old 01-29-2005, 11:39 AM
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Rodney
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Default RE: JR Servo Pulse Center Point ???????

Joeairport, and I'd also bet that if you checked for each channel, you would find a difference of about +-5% between them, i.e. the elevator and rudder will have different values although quite slight. I even found one transmitter that had a 20% change or difference between the rudder and elevator.
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Old 01-29-2005, 12:42 PM
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Default RE: JR Servo Pulse Center Point ???????

ORIGINAL: ZAGNUT

wouldn't it be great if we could program our radios directly in milliseconds instead of those irrelevant percentages?

dave
Could you be referring to the 1988 programmed ACE MicroPro 8000? The transmitter that still has features that todays radios don't have.
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Old 01-29-2005, 01:16 PM
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Default RE: JR Servo Pulse Center Point ???????

ORIGINAL: iflyj3



Could you be referring to the 1988 programmed ACE MicroPro 8000? The transmitter that still has features that todays radios don't have.

that and the even better microstar2000.


some people still look at me like i'm an idiot when i tell 'em milliseconds is far easier, then i show 'em and they just about cry...

the beauty in it is how many parameters you setup in one single programming step:

1) overall travel
2) servo center
3) differential
4) servo direction
5) oddball programming like setting both end points high and the center low...

add to that the much finer adjustment than "150%" allows, the fact that you know exactly what you're sending to your servo and you no longer need a servo tester to play around with servos...just use the radio and it's direct servo cable...



dave
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