Programming the T14SG for the Phantom

Futaba T14SG: 2.4GHz transmitter,
12+2 channels and telemetry.

In a previous article I described how I upgraded my DJI Phantom quadcopter with a Futaba R7008SB receiver. In this follow-up article, I'm now showing how to program the T14SG transmitter in order to fly the Phantom. So let's start...!

Updates:
3. I've replaced the programmable mix that I used for dual rate functionality with the intrinsic dual rate function that comes with the T14SG in its firmware. I've crossed-out the corresponding text and added a link to how to program dual rate.
2. Switch SH that resets flight timers T1 and T2 needs to be wired with RESET and not STOP. The screenshots are correct, though.
1. The text now properly reflects programming for the S.BUS2 setup.

Some YouTube videos made me think that I could manage the task of replacing the receiver and programming my Futaba T14SG transmitter. However, I opted for writing instead of filming how to program the transmitter as I find writing more suitable for this particular task. You can take your own pace when working through this tutorial without having to stop a film and rewind all the time.

How to Programm?

RC model gearheads are a flock of their own. While we finally see computer technology getting introduced also in this field, some things are still rather awkward. At least, with the more capable transmitters we can now backup our transmitter settings on SD card. But an easy documentation is still lacking ... the files on SD card are not suitable for understanding what is going on and are thus useless when you need to transfer the programming shown here to another transmitter type. So we are back at photographing LCD screen. Beautiful new technology...


But don't be afraid, this isn't going to be picture guessing. Along with the LCD screenshots I will also explain what I'm doing here. I'm sure this is a real bonus compared to simply offering a file for download that is only usable on a single type of transmitter.

Programming the Phantom

In case you purchased your T14SG with a LiPo battery, you first need to deal with the transmitter itself. To be particular, we need to properly set the warning level for the transmitter battery in this case. The default warning voltage is not suitable and must be changed in order to avoid mishaps.

T14SG Battery Warning

While the T14SG manual warns to set up the battery warning properly you are left wondering where to find the instructions to do so...

To answer my little test: the chapter is titled Warning and can be found somewhere in the middle of the manual. And the corresponding setup screen is located inside the Linkage menu. Completely illogical, isn't it? Maybe you need to be an old RC model gearhead to understand or at least accept such design. What about hiring a real document author that is worth her/his money? Oh, I forgot: no money, right?

Don't forget to adjust the battery warning level!

So back to changing the battery warning level. You'll find the desired item on the second page of the Linkage menu. You get into the Linkage menu by quickly tapping [LNK] twice in the sensor field.

Then tap on [S1] to switch to the second page inside the Linkage menu. There you will find the menu item [WARNING]. Scroll to it using the touch field, then tap [RTN] in the center of the touch field.

LiPo 2s warning.

Within the [WARNING] page scroll down to [LOW BATTERY], to the «ON/OFF» column. Here you need to set the warning voltage to 7.2V for the 2 cell (2s) LiPo transmitter battery. In cold environments you may better use 7.4V to be on the safe side.

This warning ensures that your transmitter does not run out of juice unnoticed so you don't loose control of your RC model.

With this out of the way let us now focus on the main task: programming your transmitter for flying a Phantom.

Only One Single Cable: S.BUS2

Simple wiring using S.BUS2: DJI calls this D-Bus instead.

In my description I'm assuming that you will connect your Futaba receiver R7008SB to the Naza-M flight controller using the S.BUS2. The S.BUS2 connector is the single connector near the bottom of the receiver, turned by 90° compared to all other connectors. You have to wire this connector to the X2 connector of the Naza-M chip. You can either use the existing receiver cable from the replaced DJI receiver module. Alternatively, you may want to use a dedicated 90mm long S.BUS patch cable made by Futaba as this has an almost perfect length.

Configuring the Phantom Modell

The fun starts here: MODEL SEL(ection).

We simply start our model setup by creating a new model. This way, we're that we're starting at a well-defined point with known default settings.

For reasons I will never, ever understand, Futaba puts Model management, such as creating, deleting a model, et cetera into the model selection item inside the linkage main menu. For the German-speaking RC enthusiats they are even topping this be calling the linkage menu the basis menu instead. Alas, quickly tap twice on the [LNK] field in the touch field to enter the linkage menu.

Next, go to [MODEL SEL.] and tap [RTN]. In this configuration screen we can either activate an existing model or create a new one. Actually, Futaba calls copying a model for another unknown reason creating a new model from an existing one. Well, I won't ever understand the trains of thought that seem to be typical to RC model vendors.

Create the Phantom as an airplane.

It sounds strange at first, but for our Phantom quadcopter model we will now create a new airplane model. So, using the touch field, go to [NEW] and tap [RTN].

Really? An airplane model? This surely is a quadcopter!

That's correct. The reason is that the Naza-M flight controller needs its steering signals separately, very similar to what an airplane model needs. It can't handle the partly mixed signals that a helicopter requires.


Next, we want to give our new model a name. Space is tight, so we have to get away with whooping ten characters. For instance, «DJIPhantom» perfectly fits into the available space. When the name is set, the T14SG automatically switches to the [MODEL TYPE] configuration screen. This screen is about different types of airplane models.

I'm a happy Phantom airplane ... for sure!

Luckily, we can keep everything set here as is at its default. Just make sure that the «TYPE» is [AIRPLANE]. «WING» must be set to both [NORMAL] and [1AIL]. Finally, «TAIL» must be [NORMAL]. Please see also the screen shot for reference.

For whatever reason, the RC transmitter vendors still don't know about multi rotor model in ther highly sophisticated computer transmitters. Not that such models have just appeared on the market...

Radio Link

12 channels are enough.

In this step we set up the radio link between the transmitter and the receiver. In ancient times, circa a few years ago, transmitters transmitted and receivers, well, received. Exactly the way politicians see them and us, the people: politicians send and people have to receive.

But back to our Phantom equipped with the Futaba R7008SB receiver: for our purposes, 12 channels are more than enough. To be precise, these are only 10 servo channels and two additional on/off channels. But in marketing, 12 is better than 10 so they put it prominently on the box. Like class 10 microSD cards...

As we are interested in seeing the current flight battery voltage while in flight, we need a radio link type that has the telemetry function. But since we only need the builtin telemetry base function, we better go with the link mode [FASSTest 12 CH]. This reduces control latencies as there is only a tiny data packet to be sent back to the T14SG, so cycle times are kept small for terminal-to-terminal control ... ops, wrong movie. There is also a FASSTest 14 channel link mode available which only comes into play if you either really need that amount of channels or have additional telemetry gear attached.

As battery voltages will only slowly change over time, we then set the donwlink cycle to once per second: [1.0s] (in the row marked «ACT»). This won't hurt the battery consumption noticeably as there will be only a short chirp.

Please note that in the Phantom the receiver voltage is stabilized (this is done in the PMU, the power management unit). So unless the flight battery voltage drops under this level you don't get any valuable information. But if it does, your Phantom will already have fallen out of the sky by then. For this reason, a battery failsafe is also of no use, so we leave this setting as is. Instead, we will later set up a low flight battery warning in the T14SG transmitter.

Down is the New Up...

Reversing the right channels.

An important configuration you need to make are the channel directions: they can be either normal or reversed. So, please enter the linkage menu and then select [REVERSE] from the first menu page.

For our Phantom we need to reverse the directions for the following channels: channel 2 «ELE» and 3 «THR», as well as channel 6 «AUX2» and 7 «AUX3». Make sure that these channels are set to [REV]. All other channels must not be reversed and thus set to [NORM].

We need to reverse channels 6 (AUX2) and 7 (AUX3) as otherwise the switch positions of the T14SG switches for flight mode and IOC would be the reverse of what we have learnt from the DJI transmitter. Keeping things the same will avoid making silly mistakes when flying.

Switch Setups

Next, we need to wire up some switches, in particular, switches for channels 6 and 7. These channels instruct the Naza-M flight controller in which modes to operate: channel 7 (AUX3, or U at the Naza-M) controls the flight mode, while channel 6 (AUX2 or X2) controls IOC. We also wire up the slide lever to channel 5 (AUX1 or X1) which later will be picked up by the gimbal.

Already correct.

So we straight go to the linkage menu, and this time we select menu item [FUNCTION]. Please leave the settings in the first page as is and go to the second page by tapping on [S1]. Does somebody understand why the key for switching pages is labelled S1, that is, first page??

Wire up your switches.
.

The second configuration page now is of interest to us. Here, we wire up as follows:

• we assign control of the flight modes (that is, GPS, ATTI and optionally MAN) to the right switch «SC» of the T14SG. This switch has three positions and its position is similar to the same switch on the DJI transmitter. So, connect channel 7 [AUX3] with switch [SC] (under column header «CTRL»).
• similar, we assign the IOC to the left switch «SB» of the T14SG. Again, we use a three-position switch that is located on the T14SG similar to the position of the same switch on the original DJI tranmitter. Thus, connect channel 6 [AUX2] with switch [SB].
• Finally, connect channel 5 [AUX1] with the left slide lever. It is called [LS]. Depending on your preferences, you may want to use the right slide lever or one of the two volume rotary knobs on the front of the T14SG.

This is the End! Count to 10, ...

Already correct.

Now that we wired the flight mode and IOC switches to their corresponding channels, we next need to set the end point values for the switches' top and bottom positions. We need to do this as the Naza-M flight controller interprets a switch value of +100 and -100 as invalid (or undefined, depending on your point of view). You can easily see this in the Naza-M assistent, where the channel value indicator hops to a gray area and none of the valid switch positions gets highlighted.

Luckily, we only need to tune channels 6 and 7, all other channels are unaffected. So, in the linkage menu, go to [END POINT]. Skip the first page, as its settings are correct.

Endlagen für Flugmodus und IOC.

Now change the end points of channels 6 and 7 to a new lower end point value of 80%. Using the Naza-M assistent software make sure that your Phantom correctly detects and interprets the switch settings.

In principle, we could also use a mixer, but this would be too much effort to what obviosly can be done much simpler. Just adjust the end points and you're done. Leave all other end point setting for channels other than 6 and 7 intact, that is, at 100%.

Servo Check

Checking channels.

It is time for a check that our settings to far result in correct channel values. As a convenient check we go to the linkage menu again and this time we select [SERVO]. This will display the individual channels 1 through 8, with a second paged displaying the other channels 9 and 10. Remember that channels 11 and 12 are the digital channels DG1 and DG2 when using the FASSTest 12CH link mode).

This display shows in realtime the channel values that the T14SG transmits over the air while you pull your control sticks and toggle switches. You may want to control servo directions as well as end points using this convenient display. There is one gotcha, however: Futaba displays a channel value of -100 as going up instead of down. Another RC model idiosyncrasy, me thinks.

• when to pull the throttle stick completely all way down to you, channel 3 must be at -100%.
• channel 7 must take on these three values, according to the following positions of switch SC, kontrolling the fligth mode: top position (GPS) must yield +80%, middle position (ATTI) must yield 0%, bottom position must yield -80%.
• Similar values must be yielded for the IOC switch SB for channel 6: top position at +80% and  bottom position at -80%.

Main Screen

Main screen.

In the main screen of the T14SG we're going to set up two timers. The first timer T1 should start whenever the push the throttle stick forward. T1 thus counts the flight time. After 10 minutes, it should beep to remind me that there is now time to land.


The second timer T2 acts as a come-back reminder. T2 starts at 5 minutes when you push the throttle stick for the first time, counting down. When T2 reaches zero it beeps to remind me to come back.

In order to reset both T1 and T2 we will wire up them to button SH. This switch is spring-loaded so it always snaps back to its off position.

With the telemetry function for the flight battery voltage wired up and working the timers are now of much less importance. However, they are still a nice additional function so I'm leaving them in and describe here how to set them up.

Flight Duration T1

Timer T1: flight duration.

Timer T1 is for measuring how long we are already in the air.

To set up T1 first go to the main screen. There, use the touch field to select [T1] and then tap on [RTN]. You will now see a timer configuration page as shown in the figure to the right.

Timer mode is [UP]. The alarm, which is rather a reminder, should sound at 10:00 minutes, so set this value using the touch field next to alarm.

Key SH resets the timer.

Next, wire up switch SH to reset the timer. Use the touch field to select [RESET], then tap [RTN]. This brings up another screen with an awfull number of switches the T14SG has to offer to select from. I opted for [SH].

Pushing the throttle stick starts the timer.

T1 should be started when the throttle stick is pushed, so in the timer T1 setup page go to [START]. Wire it up to J3 which is the throttle stick. You will then see another setup page displaying a gauge. Now, push the stick slightly, you should notice the arrow head moving. I'm positioning the stick just next to the first white mark, some where around -90%.On the gauge this will be in the middle between the lowest and second lowest tick mark. Select [SET] and tap [RTN]: this will save the current position of J3 as the start trigger.

The flight duration timer T1 is now set up.

Come-Back Reminder T2

Come-Back Timer.

The second timer T2 shall also start then I push the throttle stick. It starts at 5 minutes and counts back. Thus, set its mode to [DOWN].

All other settings for [START] and [RESET] are those as of timer T1.

Telemetry

Telemetry data for the battery voltages.

The T14SG has a dedicated telemetry screen, shown up to four selected telemetry data sets. When we set up a link mode supporting telemetry, that is, one of the FASSTest modes, this display is already equipped with the built-in data sets for the receiver battery voltage and an external voltage. The battery voltage doesn't help us as it is stabilized, so we only need to display the external voltage, which is wired up to the flight battery.

Live flight battery voltage reading!

Thanks to the new T14SG firmware 2.02 it is now possible to even show only a single telemetry data set. We can now remove the useless stabilized reciever battery reading from the telementry display. A big thank-you to Futaba for adding a really useful feature.

Only show the flight battery voltage, nothing else!

In order to remove the unwanted receiver battery display, first go to the telemetry display. Press the left key HOME/EXIT to do so. In the telemetry screen, now use the touch field to select [Rx-BATT.], then tap [RTN]. Don't select [RECEIVER] as this would bring you to the warning levels screen for this data set.

For SENSOR now select «----------». This is Futaba's notion for Nothing. Acknowledge with [RTN] and the setup screen will be updated with the only remaining data set for EXT-VOLT. Don't remove this one, as this is the one we want to display.

When you now return to the telemetry screen it will only display the external voltage, which in fact is the voltage of the Phantom's flight battery. Sweet and useful!

Failsafe

This is an ugly topic. The reason is that we have roughly three levels of failsafe functionality. And cascading them in general is a bad idea. I'll describe the setup of the T14SG/R7008SB in the context of a Naza-M flight controller in a separate article. Stay tuned. Okay, here it is: T14SG and the Phantom Failsafe.

A Little Help

If you like, you may want to throw in a little flight aid that reduces the rudder stick amplitude. We use a mixer for this that can be switched on and off on demand and that works on channel 4 for the rudder. I've got this idea from Arthur Konze and adapted it to the T14SG.

Note: Alternatively, you may want to use the built-in DUAL RATE functionality instead that comes with the T14SG. It's no big deal to set it up to your needs.

You'll find mixers in the model menu.

We will find the mixer setup in the model menu under the item [PROG. MIX]. This brings you to a screen of available free mixers. The T14SG has five to offer. Please note that there are many more mixers, albeit these are function-specific mixers that cannot be freely programmed.

Mixed mixers...

In the mixer page, you can use any mixer you want, as they all similar. We will simply use the first one. In another article about failsafe programming I will setup the second mixer for use with failsafe. Select the first mixer and tap [RTN] in order to configure it.

Flughilfe.

Every mixer has two configuration pages assigned and the first need to switch using [S1] to the second configuration page. We start configuration by wiring up the switch [SF] that activates and deactivates the mixer. If you see [INH] in this position, then the mixer currently is inhibited and cannot be switched on at all.

Next, set channel 4 which is assigned to the rudder functionality as the [MASTER] and [SLAVE] channel. The term rudder stems from the terminology coined by airplanes. Setting both master and slave channels to the same channel allows us to modify the channels final output. From the perspective of a signal flow-based model the whole user interfaces makes no sense, but hey, this is RC model terrain. Control theory engineers will surely cry when seeing this mess.

A little aid.

Back to page one we now set up the mixer function. Make sure the mixer function is (step-wise) [LINEAR]. Set bot end points at  -100% and +100% each to -50%. The effect now is that we are subtracting half of the channel value from itself, ending up with only half the original value. This enlarges the command stick travel to twice the original way for the same channel value.

Finally...

Check that all channels are working correctly, as well as
all switches!

Phew. We're done programming the transmitter T14SG now. Next, hook up your Phantom to the Naza-M assentant and do a dry run, checking that your Phantom receives the right commands and will react accordingly.

Power on the T14SG, then power on the Phantom, connect it to your Naza-M assistent using a working USB cable. At this time, your Phantom will rapidly blink yellow, as it entered failsafe mode because it doesn't receive any valid command. Remember that it is still in PPM mode, no S.BUS operation yet.

If not already done so, you first need to upgrade the Phantom's firmware inside the Naza-M up to version 3.16 or later. This is the first firmware to support S.BUS2. After upgrade, follow the instructions to reset and reload the correct default values into the Naza-M.

Next, in the Naza-M assistant sofware go to page «Basic» and select tab «RC» there. Select D-Bus as the correct receiver type. Don't forget to recalibrate now.

Important: As you are now using a (new and) different transmitter and receiver you have to calibrate in order to correctly have the Naza-M learn the neutral positions and maximum channel values. Use the buttons labelled START, next to the word Calibration.

Absolutely make sure that the Naza-M correctly detects all switch positions for channel U (which controls the flight mode) and channel X2 (which controls the IOC). Also check failsafe operation, if you have followed my example on setting up mixer 2 (described in T14SG and the Phantom Failsafe). Flip switch SG, then you should see channel U jumping into a failsafe position.

If something does not work as expected, check your programming of the T14SG.

Only after you have thoroughly checked that everything works as expected you are ready to go on a field and to a field test (in the true sense of the meaning). Grab your fully-charged batteries, your transmitter, and your Phantom and off you go. Enjoy your flights!