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Measuring the receiver output pulse Width

Old 03-20-2009, 05:59 AM
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Malcolm H
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Default Measuring the receiver output pulse Width

Does anyone know of a device that can be plugged into the rx and display the pulse width? The Schulze KA controllers use a fixed full throttle end point which I have been setting by trial and error and I would like to set it accurately. I'm hoping I'm not going to have to use my long forgotten oscilloscope measuring skills!

Malcolm
Old 03-20-2009, 07:10 AM
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j payne
 
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Default RE: Measuring the receiver output pulse Width

The programme box for the jeti spin 99 can give you the pulse width I am using a Schulze controller and used one to set my throtle end points on my JR 12x the travel adjust are high throtle 125 and low throtle 120 the 120 on low throtle reduces the brake just a bit the motor I am using with my Schulze controller is a Plettenberg 30 10 evo

John
Old 03-20-2009, 09:10 AM
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Default RE: Measuring the receiver output pulse Width

Malcolm-

I use the Vexa ServoXciter extensively. Can't live without it.
http://www.vexacontrol.com/xciter_details_1.html

-Ron
Old 03-20-2009, 09:25 AM
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Default RE: Measuring the receiver output pulse Width

I use the Jeti Spin Box to measure pulse width out of the receiver. I set the Spin for fixed endpoints of 1.0 and 2.0 milliseconds and then set the transmitter to 2.0 at high throttle. The low end is set to something very low, like 0.9 for throttle cut, which is used to arm the ESC. In throttle cut the system is very safe because the throttle stick is disabled so you can't accidently throttle up until you are ready to take off. When the throttle cut switch is turned off it goes to something just over 1.0 that gives me an idle of about 700 RPM. Some motors/ESCs will start in idle when you deactivate the throttle cut but my Spin needs a little kick of the throttle stick to start. I then have an idle down switch that I activate after take off that gives me just under 1.0 when the stick is pulled back to activate the brake. I normally leave the Idle down switch on all during flight but sometimes turn it off for spins so the motor won't stop completely. I really need to decide which way to go and do it the same all the time.

I also have a Hitec servo programmer that will measure pulse width but it is not as user friendly.

Jim O
Old 03-20-2009, 11:14 AM
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woodie
 
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Default RE: Measuring the receiver output pulse Width

I also use the Jeti Spin Box for measuring pulse width. I have found it to be a very useful tool beyond programming the Jeti ESCs.

I would make one safety comment on Jim's description of throttle cut. On the Futaba radios, I believe the later models like the 14MZ and 12Z behave as Jim describes with throttle cut basically disabling the throttle stick preventing accidents if the throttle stick is accidently bumped. However, not all radios behave this way. Some basically use throttle cut to lower the idle and kill the engine but the throttle stick is still active. Be aware of what your radio does in throttle cut mode.

Like Jim, my Jeti ESC needs just a little bump of throttle to get the motor running if I set the idle very low.

Woodie
Old 03-21-2009, 01:37 PM
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Malcolm H
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Default RE: Measuring the receiver output pulse Width

Managed to borrow a Spin box at a contest today. Thanks guys!

Malcolm
Old 03-22-2009, 01:33 PM
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Default RE: Measuring the receiver output pulse Width


ORIGINAL: Malcolm H

Managed to borrow a Spin box at a contest today. Thanks guys!

Malcolm
Where were the fixed endpoints? I assume they are not adjustable on the Shultze?

Jim
Old 03-22-2009, 01:51 PM
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Malcolm H
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Default RE: Measuring the receiver output pulse Width

Haven,t had a chance to check yet will post once I have.

Malcolm
Old 03-24-2009, 04:16 AM
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Malcolm H
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Default RE: Measuring the receiver output pulse Width

Jim,

Played with the Spin box and the Schulze controller last night.

Schulze state: Full throttle 2.0 mS, Off 1.5mS and Full brake 1.0 mS, Brake is fully proportional between 1.5 and 1.0 mS

Without adjusting anything from my flying settings I measured: Full Throttle 2.008 mS, Off 1.480 mS, Flight idle, 1.488 mS, My max. brake setting 1.100 mS

Based on this I don't know whether the Schulze off position is slightly lower than their published setting or whether the Spin box is slightly out of calibration. In any event I decided to leave the full throttle setting as is.

Malcolm

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