7955 Servo Movement On Powerup
06-19-2014, 06:52 AM
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7955 Servo Movement On Powerup
I'm setting up a plane with five Hitec 7955 servos two of which move on power up. The rudder moves about 1" in one direction and then centers itself. The left elevator servo moves up to full stroke in one direction then centers itself. The left elevator is programmed to follow the right elevator per the DX-6 manual. AR6210 receiver. Is this a problem or is it normal?
Chuck
Chuck
06-19-2014, 06:14 PM
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Recent experience with AR6200 and DX7C. Wing setup is for single aileron and single flap servos. If receiver is powered with out transmitter the flap servo is driven to max CCW position. For my plane this is beyond full up or retracted flap position, never returns. With transmitter on first then receiver the flaps channel will drive pass full up setting until the system has linked (lasting 3 to 4 seconds), then everything is normal. This system works the same with either DX8 or DX7C transmitter. I would expect all channel going to center. Now that I have install a really strong servos for the flaps I had to re-index the servo control arm so they are driven to hard mechanical stop and not into the control linkage.
D
D
06-20-2014, 02:20 AM
#4
Are you using a genuine AR6200, or one of the counterfeits?
Have you bound the receiver with the flaps in the desired position? A genuine product will send the servos to the at-bind position of the channels.
The transmitter used makes no difference.
Andy
Have you bound the receiver with the flaps in the desired position? A genuine product will send the servos to the at-bind position of the channels.
The transmitter used makes no difference.
Andy
06-20-2014, 02:51 AM
#5
Senior Member
Recheck the Flap settings in the TX for travel, offset,trim,mixing, etc.
Next Re-bind. It's remotely possible that the flap servo is going to one end with no input signal, then returning to the preset position, and working
normally.
Next Re-bind. It's remotely possible that the flap servo is going to one end with no input signal, then returning to the preset position, and working
normally.
06-20-2014, 03:11 PM
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First up, I apologize to Chuck adding to his question.
As for my issue with Spectrum receiver operation. I did bind with the controls in neutral, throttle at minimum and flaps in the full up (retract position). The receiver was purchased from Horizon Hobby and has Spectrum Logo on the case. As for a servo with no signal they may drift, in my case they are commanded by the receiver to position to the max CCW. Notice that all I have to do is power the receiver for this condition to be present. There ia another undesirable condition with the GEAR channel. I use this channel to control my ignition power source and when the receiver is powered without the transmitter being on it will enable the ignition, that is the gear channel putout a minimum pulse width signal which I think is CCW, When I speak of CCW, I mean for servos like Futaba, Spectrum, HD, not Hi-Tec.
D
As for my issue with Spectrum receiver operation. I did bind with the controls in neutral, throttle at minimum and flaps in the full up (retract position). The receiver was purchased from Horizon Hobby and has Spectrum Logo on the case. As for a servo with no signal they may drift, in my case they are commanded by the receiver to position to the max CCW. Notice that all I have to do is power the receiver for this condition to be present. There ia another undesirable condition with the GEAR channel. I use this channel to control my ignition power source and when the receiver is powered without the transmitter being on it will enable the ignition, that is the gear channel putout a minimum pulse width signal which I think is CCW, When I speak of CCW, I mean for servos like Futaba, Spectrum, HD, not Hi-Tec.
D
06-22-2014, 09:54 AM
#7
Man, I've got ALL sorts of questions here and one is for Andy whom I rarely disagree with but it looks like he corrected the information later in the thread....
When bound after setup, digital servos should not deflect when the rx is turned on and before it links with the tx.
Next question is for the OP; what in the world are you planning on flying with five 7955 Hitec servos and a six channel rx? The reason I ask is that while the bigger Spektrum/JR DSM2/DSMX rx's will take 35 amps and burst to 50 amps, I'm not entirely sure that little six channel will carry all the power those big Hitecs can suck up when working. Maybe Andy can find a specification on that question, I've never been able to find a rating for the smaller rx's. Next is how are you going to get power into the rx? Those servos will need a chunk more power than the max 4 amps continuous that a standard size servo connector can handle and that's only if they are good quality with gold plated pins. You go cheapy silver pin connector extensions and loose fitting housings, you'll be lucky to get 2 1/2 amps before they melt.
Just a few idle thoughts....
When bound after setup, digital servos should not deflect when the rx is turned on and before it links with the tx.
Next question is for the OP; what in the world are you planning on flying with five 7955 Hitec servos and a six channel rx? The reason I ask is that while the bigger Spektrum/JR DSM2/DSMX rx's will take 35 amps and burst to 50 amps, I'm not entirely sure that little six channel will carry all the power those big Hitecs can suck up when working. Maybe Andy can find a specification on that question, I've never been able to find a rating for the smaller rx's. Next is how are you going to get power into the rx? Those servos will need a chunk more power than the max 4 amps continuous that a standard size servo connector can handle and that's only if they are good quality with gold plated pins. You go cheapy silver pin connector extensions and loose fitting housings, you'll be lucky to get 2 1/2 amps before they melt.
Just a few idle thoughts....
06-22-2014, 10:30 AM
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Zeeb,
I got this thing all tangled up. My initial response was to Chuck to add my observation of a similar issue with servo displacement at power up of the receiver only. My configuration is a Gas powered ECM Stuka which only needs 6 channels. I appreciate your comments about the servo current requirement as I had a steep & expensive learning curve. I now build my own power distribution and do not draw servo power from the receiver. Andy's comments put me on track to research and understand my issue with Specktrum system. I found that AR8000 does not any issue related to what I wrote about. AR6210 does not have the AUX1 channel issue of driving the channel with a full CCW command at power up and until Tx link is established. This seems to be only in the AR6200. Both AR6200 and AR6210 will drive the gear channel to full CCW command at power up of ther receiver. Also the AR6200 would always cycle the gear channel to full CW command when the Tx link was (is) lost. This action kills my power to the ignition module which is real worrisome. Fortunately my AR6210 does not act this way,
So my take away is know your receiver which is a little expense when I have to buy one to figure it out. If I use a $130 channel receiver life is good except I only need a 6 channel. That's only $$.
I got this thing all tangled up. My initial response was to Chuck to add my observation of a similar issue with servo displacement at power up of the receiver only. My configuration is a Gas powered ECM Stuka which only needs 6 channels. I appreciate your comments about the servo current requirement as I had a steep & expensive learning curve. I now build my own power distribution and do not draw servo power from the receiver. Andy's comments put me on track to research and understand my issue with Specktrum system. I found that AR8000 does not any issue related to what I wrote about. AR6210 does not have the AUX1 channel issue of driving the channel with a full CCW command at power up and until Tx link is established. This seems to be only in the AR6200. Both AR6200 and AR6210 will drive the gear channel to full CCW command at power up of ther receiver. Also the AR6200 would always cycle the gear channel to full CW command when the Tx link was (is) lost. This action kills my power to the ignition module which is real worrisome. Fortunately my AR6210 does not act this way,
So my take away is know your receiver which is a little expense when I have to buy one to figure it out. If I use a $130 channel receiver life is good except I only need a 6 channel. That's only $$.
