Author Topic: Telemetry Transmitters  (Read 10967 times)

Alan_Perse

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Telemetry Transmitters
« on: November 07, 2011, 15:12:13 PM »
Hi all,
What's the difference between a telemetry enabled transmitter and a full telemetry transmitter. I know the full telemetry is probably better, but why? The transmitters I'm referring to are multiplex by the way.

Fred

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Telemetry Transmitters
« Reply #1 on: November 08, 2011, 08:18:30 AM »
Hi Alan,

I see nothing in the MPX catalogue about full telemetry / enabled telemetry transmitters  :?:
My guess would be that the Full telemetry TX have the built in 2.4ghz, the enabled ones, are with added external / internal modules (aka, the rest  :?: ).
Education is important, but flying RC planes and gliders is importanter!

Alan_Perse

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« Reply #2 on: November 08, 2011, 10:13:42 AM »
Hi Fred.
I was looking at the modelmaniacs website. I have bought a few things from them before, there service is quite good. They have the 2.4Ghz Cockpit SX transmitter listed as either telemetry enabled or full telemetry. The full telemetry is more expensive so it is probably better than the telemetry enabled ones. Just wanted to know why. I guess your explanation explanes it, thanks  :D .

Fergal Gordon

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Rx battery warning level
« Reply #3 on: February 27, 2012, 18:33:52 PM »
Hi Everyone,

I have a question about Multiplex M-Link receivers.  I have recently converted my Evo 9 from 35 MHz to 2.4 GHz.  By default I get the Rx battery voltage and battery connection quality by telemetry.  I get an audible warning on the Tx when the Rx battery reached 4.8 V.  I think this too for my 4 cell NiMH battery.  I have only used about 300 mAh out of a nominal capacity of 1700 mAh when I get the warning.

I have searched the Tx and the Rx manuals and web, but I cannot find where I can alter this warning level.  Does anyone know if this 4.8 V warning level can be changed and if so, how.


Best regards,


Fergal

Alan_Perse

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« Reply #4 on: February 29, 2012, 20:59:07 PM »
Hi Fergal,

I was looking at the manual for my M-Link receiver and it appears that if you want to change any of the presets on your receiver you will have to connect it to a devise called a MULTImate (from multiplex). From what I have read on the internet it appears you can used this to configure Receivers and other sensors that you can connect to your receiver, it is also a Servo tester. You can also connect your receiver to your PC and use a software called RX DataManager. I'm not sure if there is another way. I hope this helps.

Fergal Gordon

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Telemetry Transmitters
« Reply #5 on: March 03, 2012, 19:17:27 PM »
Hi Alan,

Thanks for the suggestions.  The manual for the M-Link Tx module (HFM4 M-Link)) states the following:

"If you use a telemetry-capable receiver, the actual voltage of the receiver power supply is displayed on the transmitter’s integral screen.  If the voltage falls below the set minimum value, an audible signal warns you that the battery is almost flat."

Section 12 of the same manual also states:

"The 2.4 GHz ISM band offers the facility to transmit model data
back to the transmitter. If you are using a telemetry-capable
M-LINK receiver, the actual voltage of the receiver power supply
will be displayed directly on the integral screen of your ROYAL-
evo, ROYALpro or ROYALpro M-LINK transmitter. If the battery
voltage falls below a certain threshold, the transmitter also emits
an audible signal to warn you that the receiver battery is almost
flat.

For more information on this feature, please refer to the opera-
ting instructions supplied with your telemetry-capable M-LINK
receiver."

The Tx module manual mentions "a certain threshold", but gives no indication of its level or how and where to adjust it.

The Rx manual in not any more informative either.

I have downloaded the MultMate manual and there is no sign of adjustment of the low Rx battery warning level.  The is a threshold voltage level for counting voltage errors and this is adjustable.  However, this is a different setting than the low voltage warning level.

There seems to be nothing in the main Tx manual in relation to telemetry or M-Link.

It is a bit of mystery how this feature is not well documented, given how well Multiplex generally document their products.  One would expect that this setting should be in the model set-up, as each model could have a different battery pack and therefore would require its own low voltage warning level.  Hopefully, this will be addressed in a future software upgrade.

Regards,

Fergal

Happy Days

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« Reply #6 on: March 03, 2012, 21:05:27 PM »
Just a thought Fergal,……

As I read what you’ve explained, you are using a 4 cell NiMH battery . As you probably already know, the nominal working voltage of such a battery is 4.8v. So I’m wondering why Multiplex would want to warn you about the state of charge of your  battery when it’s operating at its correct voltage. :?:  (I’m assuming it would only emit a warning if the voltage was low.)

Therefore, I’m thinking, that perhaps the warning alarm assumes that you would be using a 5cell battery (Which has a nominal voltage of 6v.) The reason being is that if the voltage on a  5cell battery were to drop to 4.8v then it would be at a low state of charge.
In other words, I’m suggesting that maybe the system assumes you’re running with a 5cell battery.

Solution = use a 5cell battery?

Wot d’ y’ fink?
Try not to run out of airspeed, altitude and ideas....... all at the same time.

Happy Days

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« Reply #7 on: March 04, 2012, 06:51:35 AM »
I’ve just done some on-line searching and the above is irrelevant. :roll:

I can’t actually find an on-line manual for your Tx but I did turn up the following Fergal which states that the warning voltage of the Rx battery is variable,…

"Feedback channel / Telemetry
If you use a receiver with telemetry facilities (min. RX-7-DR M-LINK or RX-9-DR M-LINK), the actual voltage of the receiver power supply is displayed on the transmitter screen. If the voltage falls below a (variable) minimum value, an audible warning signal alerts you that your receiver battery is almost flat. This means that you are constantly aware of the state of the receiver battery, as well as the condition of the transmitter battery (as previously). An important extra safety feature!

See page 21 for details of telemetry sensors.
"

That’s all I could find written in English. But just refering to my previous post I recon at present your system is set up assuming that you’re using a 5 cell rx battery because with a 5cell, 4.8v is the level of a discharged battery

I know that’s not much use to you, but it’s the best I can come up with old fruit.

Keith
Try not to run out of airspeed, altitude and ideas....... all at the same time.

Fergal Gordon

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« Reply #8 on: March 04, 2012, 18:13:08 PM »
Hi Everyone,

Thanks for all the help.  I am beginning to think the voltage threshold for the low Rx voltage error count is the same threshold for the audible warning on the Tx.  The default setting is 4.5 V, which on face value is a reasonable level.  However, I have done some tests on the ground, where I can focus on what is happening on the Tx screen.  I would appear that when there is an increased current draw, e.g., several servos moving fast, the voltage can momentarily drop by 0.3 to 0.4 V below its steady level.

When I am flying, it would appear the steady voltage first drops to about 4.8 V.  Then there is a momentary drop to the threshold voltage of 4.5 V.  I then level the plane, centre the sticks and when I look at the Tx screen I see 4.8 V.

If this is correct, then all I need to do is reduce the threshold voltage down to between 4.0 and 4.2 V.  The receiver will still work down to 3.5 V, so reducing the threshold to 4.0 V should not be problem.  I just need a MultiMate to program the receiver.


Best regards,


Fergal

Alan_Perse

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« Reply #9 on: March 04, 2012, 18:52:03 PM »
Quote from: "Fergal Gordan"
I am beginning to think the voltage threshold for the low Rx voltage error count is the same threshold for the audible warning on the Tx.


Forgive me Fergal if you know this already, but isn't the voltage of the TX battery 7.2V. If you set the threshold to 4.8V you will lose power before you get a warning.

Fergal Gordon

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« Reply #10 on: March 04, 2012, 19:22:59 PM »
Hi Alan,

Yes you are right, the Tx battery warning level should be set to about 7.2 V.  However, this is not the issue in question.  My Tx also displays the Rx battery voltage (M-Link telemetry) and the Tx also gives an audible warning if the Rx battery is low.  I start getting these warnings when the Rx battery still has 80 to 90% of its charge.

It would appear that although the warning is made by the Tx, the threshold is set in the Rx.  And this would make sense, as each model would have its own threshold, depending on the battery configuration and the current draw.  The other logical place for this setting would be in the model menu of the Tx.  However, there is no such setting there.

The solution is to get a MultiMate and use it to program the Rx with the appropriate settings.  The MultiMate got a good review in the February edition of RC Model World magazine.  Hopefully, this will do the trick.


Best regards,


Fergal

Fergal Gordon

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« Reply #11 on: March 28, 2012, 23:06:52 PM »
Hi Everyone,

I just got to the bottom the problem with Rx battery level warning.  As mentioned before, I was getting Rx battery low warnings after about 20 min flying time.  The problem has turned out to be a faulty on/off switch.

I have fitted a new switch and have had about 1.5 hours flying before a got a low level warning.  This is more realistic.

I appear to have had a bad contact and was probably switching off momentarily and dropping the voltage level.  Luckily, the plane did not switch off completely in the air.  It looks like the upgrade to M-Link system has paid for itself.

Best regards,

Fergal.

Happy Days

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« Reply #12 on: March 29, 2012, 08:07:34 AM »
Occam's razor;......

“All other things being equal, generally the simplest solution is the correct one!”

At least you got to the bottom of the matter Fergal. :clap:
Try not to run out of airspeed, altitude and ideas....... all at the same time.

Alan_Perse

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« Reply #13 on: March 29, 2012, 22:44:45 PM »
Good to hear you got it sorted Fergal. Have you fixed your gliders yet?

Fergal Gordon

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« Reply #14 on: March 30, 2012, 19:01:47 PM »
Hi Keith,

Don't forget KISS and the parsimony principle!


Fergal