Binding the Spektrum radio system

[Tim Mackey]

Many servos will cycle and move "randomly" when power is applied with no signal, others such as the spektrum digitals will simply stay put until a valid "neutral" signal is received from the tx.

This can often cause unrequired movement, such as on retract servos.

IE: Your model is laying on the ground, with retracts up.

You check the tx gear switch on the tx is set to "UP", then switch it on.

Then you switch on thre rx - but as soon as the rx is powered, the retract servo moves, and the poor old legs are strained against the weight of the bird

A few seconds later, after the rx and tx "talk to each other" the servo returns to its normal, commanded position. This is not actually anything to do with failsafe presets, or binding, but just a symptom of certain servos versus others.

I have now taken to fitting a separate power switch into the retract servo line, and I only activate this after the tx and rx are talking.

[Shaunie]

Hi Tim,

I agree with all you say but the servo behaviour was definitely different after binding for the second time. When I finally get round to building something with retracts I will definitely fit a second battery pack with its own power switch.

Just performed a test, if the servos are manually moved to off-centre positions with the power off, when the Rx is powered on they immediately centre even with the Tx off. I seem to remember that prior to the second bind that the servos on the aux channels went to different positions and adopted their correct positions after the signal was picked up from the Tx. Perhaps its just the neutral positions that are stored. Tried turning the Tx off with control inputs set and they remained where they were, confirming the lack of failsafe on all channels.

Shaun.

[TigerOC]

I had an interesting experience yesterday and it relates to input voltage during binding.

I am currently doing a scratch build of a very old design for indoor flying. I ordered a Orange 410 because it only weighs a few grams. I didn't have a 4xAA pack to hand but had a Life 2S receiver pack handy. I plugged this into the rx and tried to bind it. Refused to bind. Tested the transmitter on a bound receiver and it was fine. Took a new Orange R615 and connected that and that successfully bound.

There are no specs on the R410 input voltage range but the 6XX range have a 4.8 - 9V range. Before raising a warranty claim on the rx I decided to hook it up to a 4xAA battery pack and try that. Bound with no problem at all. Clearly the R410 only operates in the 4.8 - 6V range.

Take Tim's advice and use a 6V pack when binding.

Rob

[Jan Kristensen]

It is recommended to do a second bind especially if any servo channels are reversed during the servo functional check/setup at the first bind. The second bind ensures that the correct failsafe position is set in the receiver.

The min distance of approx 1 meter between Tx and Rx during binding is important, otherwise the binding might fail and the Orange Rx's are more sensitive to that than the Spektrum Rx's.