The Tellurian (and All), Whoa - My apoligies, I have FrSky D8R-II recievers where the telemetry sockets are in the side of the RX, I just looked what a D6FR looks like and can now see how easily plugging into to wrong port can/could happen!!!!!!!

I'm far, far from perfect many a time I've plugged servo leads in upside down, the ailerons into the flaps, I could go on, but the I'd really be outing myself as a total moron!!

-B!LL!

(Rider: Moreover, therefore I should do some research before I open my big trap!)

It is very easy to plug a servo/batttery into the A2 port of a D6FR, what I do now with mine when I get them is to fit an old servo plug (no wires) onto the pins.
Case of, wont make that mistake again !!

Don't be so hard on yourself, Bill. It happens to the best of us. I usually just say, "Oh, I see." and just move on.

My favorite line of all time from Saturday Night Live.... Rosana Rosnadana, "Never mind." Classic!

Originally Posted by Fugitive_Bill

The Tellurian (and All), Whoa - My apoligies, I have FrSky D8R-II recievers where the telemetry sockets are in the side of the RX, I just looked what a D6FR looks like and can now see how easily plugging into to wrong port can/could happen!!!!!!!

I'm far, far from perfect many a time I've plugged servo leads in upside down, the ailerons into the flaps, I could go on, but the I'd really be outing myself as a total moron!!

-B!LL!

(Rider: Moreover, therefore I should do some research before I open my big trap!)

Bit of advice required. I use a Multiplex Evo 9 with an frsky Universal module and an frsky FLD-02 . This setup works very well, giving me rssi values during flight. I've left the rssi alarms set at the 45 and 42 default values.

When flying a glider fairly high and some distance away, I sometimes get a single bleep, and the rssi drops to 45. I've never had the double bleep (42). Most of the flight shows the rssi at about 50 to 65.

I've also used Multiplex's own M-link system, and with a telemetry receiver, the signal level shows 100% most of the time, occasionally dropping to 90%.

Does this mean that the Frsky system is not as good as M-link,or is it just how each brand shows telemetry values.

Also, at what level of rssi does the frsky system actually lose control? I had a few problems with the early Frsky gear, and am still a bit nervous.

Sorry to go off track, but:-
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a)if I use the a2 input to monitor the voltage of an ISOLATED (ie stand alone) battery, do I just need to connect between a2 and its ground, or, do I also need to tie its ground to the -ve of the servo bus???
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b) I was going to also connect a momentary push button to short the a2 input to ground to test tx alarm sounds.
Is this a bad idea?
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please advise.
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Many tks, steve

Originally Posted by SteveM

Sorry to go off track, but:-
-
a)if I use the a2 input to monitor the voltage of an ISOLATED (ie stand alone) battery, do I just need to connect between a2 and its ground, or, do I also need to tie its ground to the -ve of the servo bus???
-
b) I was going to also connect a momentary push button to short the a2 input to ground to test tx alarm sounds.
Is this a bad idea?
-
please advise.
-
Many tks, steve

a) You can't connect a battery directly to the A2 port or you will burn it. you need a voltage sensor between the battery and the receiver. this sensor is a voltage divider. the voltage at A2 can't exceed 3.3V

b) using the voltage divider (sensor) the push button won't be needed because when there is no battery connected, one of the resistors from the voltage divider is already pulling the A2 to ground.. so the alarm will sound.

Thanks for that, but it will be across a 10k preset, adjusted so as not to exceed 3.3v.

I would prefer a test switch.....is there any danger if shorting a2 to its ground?

With regards to my query a) above, the reason I ask is that I am aware that, contrary to above, if a flight pack is connected to A2 , which already has earth continuity to rx via sbec, for example, them only the (attenuated to < 3.3v) +ve connection should be made......if the a2 earth is also connected, something bad happens.
I just wanted to check that the rx is happy configured as suggested.

Pls comment if you can.

Much appreciated, steve

Originally Posted by jhsa

You can't connect a battery directly to the A2 port or you will burn it. you need a voltage sensor between the battery and the receiver. this sensor is a voltage divider. the voltage at A2 can't exceed 3.3V

And therein lies the answer to the bricked D6fr RXs!

Originally Posted by SteveM

Thanks for that, but it will be across a 10k preset, adjusted so as not to exceed 3.3v.

I would prefer a test switch.....is there any danger if shorting a2 to its ground?

If you do that with the battery on, there are chances that you could short the battery to ground through the first resistor of the divider and the button. I wouldn't recommend it.

With regards to my query a) above, the reason I ask is that I am aware that, contrary to above, if a flight pack is connected to A2 , which already has earth continuity to rx via sbec, for example, them only the (attenuated to < 3.3v) +ve connection should be made......if the a2 earth is also connected, something bad happens.
I just wanted to check that the rx is happy configured as suggested.

Pls comment if you can.

Much appreciated, steve

Use only one of the ground connections

Originally Posted by Fugitive_Bill

The Tellurian (and All), ... snipped

-B!LL!

No worries M8, I should have explained how it happened in the first place.

Richard

Thanks for your response.
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Correction - my rx is powered by a seperate pack.
The ESC is opto.........I presume that the rx gets its flight pack ground via the ESC, despite it not having a bec?
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To clarify my "isolated" set up into A2;
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What I am actually doing is calibrating the a2 input, using a single li-ion cell and one of these:-
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http://www.ebay.com/itm/LM2577-DC-St...E:L:OC:GB:3160
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So, I remove say 70% flight pack capacity, using charger, and then measure on load voltage after 5 secs at full throttle.
I then disconnect all, and use the above pcb, powered by a single Li-ion cell to set that voltage.
10k preset then takes this voltage down to something sensible, say 2.6v, and plug into A2.
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Then set tx to just alarm at this level.
Then....repeat on all my leccy planes/helis, always keeping the 2.6v constant.
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The pcb is excellent.....once output set at anything between 4 and 35v, it will reliably regulate this regardless of input voltage applied, as long as Vi< Vo.
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So, from your comments I suppose I will connect rx supply pack and calibrate using pcb above with pot ground connected to A2.
Then, remove pcb and wire balance socket (disconnected 'til esc connected) across pot but disconnect its ground into A2.
Connect up the opto ESC, which in turn will provide the only flight pack ground path for the receiver.(I may be wrong on this!)
Connect pot to lipo balance connector.
If I connect test push switch between pot wiper and ground, and press it, the balance lead is still seeing approx 7kilohm load.(due 5s set up reducing to 2.6V)
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Apologies if I seem to be making things over- complicated, but the above sequence seems a more comfortable option than having a 2400W hotliner screaming away while I set frsky alarm thresholds in the DHT.
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Others may find the step up converter useful.....it's very cheap.
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If anyone has had the patience to read this post, and can see anything wrong with my cunning plan, please shout.
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Rgds, Steve

Originally Posted by SteveM

So, I remove say 70% flight pack capacity, using charger, and then measure on load voltage after 5 secs at full throttle.
I then disconnect all, and use the above pcb, powered by a single Li-ion cell to set that voltage.
10k preset then takes this voltage down to something sensible, say 2.6v, and plug into A2.

Steve, make sure that with full battery you don't have more than 3.3V between the wiper of the pot and ground. that's the A2 input, right? Yes, I find it a bit confusing but I'm sure others will also give their opinion.
I think (by your description) if the esc wasn't supplying ground to the receiver, then it wouldn't work..

Originally Posted by SteveM

Connect up the opto ESC, which in turn will provide the only flight pack ground path for the receiver.(I may be wrong on this!)

A true opto ESC would have no electrical connection between the motor battery and the receiver. You might have to run a common connection from motor battery negative to the receiver negative.
If you have a BEC in the circuit it probably already makes this connection.

Pat MacKenzie

Originally Posted by aduncan

When flying a glider fairly high and some distance away, I sometimes get a single bleep, and the rssi drops to 45. I've never had the double bleep (42). Most of the flight shows the rssi at about 50 to 65.
I've also used Multiplex's own M-link system, and with a telemetry receiver, the signal level shows 100% most of the time, occasionally dropping to 90%.
Does this mean that the Frsky system is not as good as M-link,or is it just how each brand shows telemetry values.

It sounds like Multiplex is monitoring the ratio of correct information going through to the servos, while FrSky is giving the actual signal level. To compare the two, one would need to know at what signal level the FrSky begins to feed less than 100% correct information to the servos I guess that the 45 and 42 alarm thresholds have been chosen as default accordingly.
Both approaches have their merit.

I want to add about the above that AD inputs can't be damaged by a higher than 3.3V voltage applied directly, they are protected internally.

The schematic has been posted and discussed here:
https://www.rcgroups.com/forums/show...3#post16900284