Futaba Channel Assignments

This page is a translated version of the page MBPlus AttitudeControl-HowToSetupTX and the translation is 100% complete.


Setting up a separate switch channel for AttitudeControl

In this example we use a Futaba T14SG with R7008SB SBus receiver. The procedure is basically the same on all types of transmitter systems. For this type of application it is mandatory to use a system with singleline receiver output like SBus, SRXL, SPPM or Spektrum remote satellite signal.

Using a Standard type receiver assigning channels and using a separate switch channel for AtittudeControl is NOT applicable as here you can only connect 5 channels to Microbeast and the channel assignment is fixed to the receiver output wires!


We use the default channel ordering here. Make sure that the functions of your transmitter are assigned to the same output channels as written in the MICROBEAST PLUS manual. On the Futaba transmitter we use the FUNCTION menu to check and assign functions. As channel 7 is used to switch AttitudeControl we must assign some actuator to this channel. On the Futaba transmitter the channel is designated as AUX channel which means this is a simple proportional channel without any special functionality.
We choose switch SF to actuate the channel 7. In the servo monitor we can see how the deflection of channel 7 is changing... ...when we flip switch SF


After the basic transmitter setup is done we have to choose the receiver type and assign the functions by choosing the default channel assignment for our SBus system. Before doing so make sure the receiver is properly bound to the transmitter and the receiver is sending a serial line signal on the appropriate output (in our case we have to setup the receiver so it is sending a SBus signal on the output 8/SB by setting the receiver to "Mode B", see receiver manual).



Note you must go through the complete receiver setup menu until you reach the menu end (all Menu LEDs flashing). Otherwise your settings will not be stored.



Now power off and on again. MICROBEAST PLUS will perform initialization sequence. When the init is finished perform basic setup procedure (if not already done). When the heli is ready to fly open Parameter menu by briefly pushing the button while in operation mode and directly go to menu point L by skipping the other menu points pushing the button repeatedly. At menu point L choose your desired AttitudeControl mode and save it by again pushing the button briefly. If using a AttitudeControl mode with collective pitch input you may change the pitch at menu point M. When out of the Parameter menu check if AttitudeControl reacts correctly when flipping your AttitudeControl switch.


Don't forget: AttitudeControl gain and status will only be shown each time after the gain changes which is the case when flipping the switch. After 8 seconds the Menu LED will go off and the Status LED color changes back to blue or purple showing the tail gyro mode.


Setting up AttitudeControl using the gyro gain channel

Especially when using a transmitter with 6 channels only or when using a receiver with "Standard" 5-wire layout the channel for adjusting tail gyro gain (channel 5) can also be used to activate/deactivate AttitudeControl. Here instead of toggling the tail gyro between "Normal-Rate" and "HeadingLock" mode you activate the AttitudeControl when changing the direction of gyro channel. The tail gyro can only be operated in "HeadingLock" mode. When adjusting the throw in the direction where AttitudeControl is OFF, this will change the tail gyro gain. When adjusting the servo throw of the gain channel in the direction where AttitudeControl is ON, this will change the gain of AttitudeControl.


To setup MICROBEAST PLUS for this kind of operation you must perform the function assignment in receiver setup menu manually as by default it is intended that a separate channel is used for AttitudeControl.



In Receiver setup menu we choose the correct receiver type (in this example we use a Spektrum remote satellite in combination with a Spektrum DX6 transmitter) and assign the transmitter channels to the functions by moving the appropriate control sticks on the transmitter.




Last step is menu point N. Move the throttle stick to motor off position and teach this position for failsafe function by pushing the button briefly. The end of receiver setup menu is shown by all LEDs flashing.

Note you must go through the complete receiver setup menu until you reach the menu end (all Menu LEDs flashing). Otherwise your settings will not be stored.



Power off and on again. MICROBEAST PLUS will perform initialization sequence. When the init is finished perform basic setup procedure (if not already done). When the heli is ready to fly open Parameter menu by briefly pushing the button while in operation mode and directly go to menu point L by skipping the other menu points pushing the button repeatedly. At menu point L choose your desired AttitudeControl mode and save it by again pushing the button briefly. If using a AttitudeControl mode with collective pitch input you may change the pitch at menu point M. When out of the Parameter menu check if AttitudeControl reacts correctly when flipping your AttitudeControl switch.

Flipping the switch into one direction AttitudeControl is ON. This is shown by Menu LED G lighting up while the Status LED is red. By adjusting the servo throw of the gyro channel into this direction you can adjust the AttitudeControl gain later. Flipping the switch to OFF position, Menu LED A will flash while the Status LED is red. If the switch reacts inverted use your transmitter's servo reverse function and reverse the gyro channel (channel 5)! Adjusting the servo throw of the gyro channel into this direction will change the tail gyro gain which is indicated by the yellow Menu LED in combination with a blue Status LED.

Don't forget: AttitudeControl gain and status will only be shown each time after the gain changes which is the case when flipping the switch. After 8 seconds the Menu LED will go off and the Status LED color changes back to blue showing the tail gyro mode.


Discussion

The Beginners' Guide to RC Protocols


POST 1 - Table of Contents (also protocols, frequencies, modulation types)
POST 2 - Various Protocols used in RC
POST 3 - The 2 major channel sequences
POST 4 - Walkera protocol
POST 5 - FrSky protocol
POST 6 - FlySky protocol
POST 7 - DSM2 & DSMX (Spektrum) protocols
POST 8 - Futaba protocol
POST 9 - KN protocol
POST 10 - HiSky protocol
POST 11 - IIX protocol
POST 12 - LINK to Various MicroChips used for RC in the 2.4MHz band
POST 13 - Cheerson (YD717 protocol)
POST 14 - Miscellaneous stuff that may or may not help
POST 18 - LINK to Receiver Protocols


BACKGROUND:
I have tried to write this thread for others like me, i.e. non-geeks or non-hackers. I use that term affectionately. I admire the ability to understand software code and write it. And I admire those that understand electricity and how to wire things with diodes, transitors, etc. so they will do whatever you want. I have very little understanding of writing code or how to do much software installation unless it is written very plainly in English and in great detail. Wiring diagrams help very little unless they are very basic, but I really need actual pictures. I can solder enough to change out a battery terminal, but not much more. As I pick up bits & pieces of info here and there I will add it to my blog here.

GENERAL STUFF:
PROTOCOLS, FREQUENCY BANDS & MODULATION TYPES

1. Protocols:Protocols have to do with how signals are formatted. Each protocol has its differences in the signal's format. Protocols are independent of frequencies.

2. Frequency Bands: There are 2 major frequency bands used in RC.

a.) The Citizens Band (CB) 27 - 75MHz band: The CB band includes some of the fixed frequencies from 27MHz to 75MHz. There are 4 Frequency Bands and each is divided into Channels. In the USA the Frequency Band for Model Aircraft is 72MHz, 50 Channels numbered 11 to 60. Each channel has 20KHz of separation. For surface models such as Cars, Boats, Robots, etc. the band is 75MHz, 30 Channels numbered 61 to 90. In most European countries the Frequency Band for Model Aircraft is 35MHz, 36 Channels numbered 55 to 90. For surface models the band is 40MHz, from 40.665 to 40.995MHz.

b.) The 2.4GHz ISM (Independent, Scientific, Medical) band. The ISM 2.4GHz band is a new frequency band for the RC hobby and is used with frequency hopping protocols. It starts with 2.4000GHz and goes up to 2.4835GHz. Each manufacturer of Txs design and use their own unique protocols for frequency hopping within the band.
Link to Frequencies that are allowed here: www.modelaircraft.org/events/frequencies.aspx

3. Modulation Types: Modulation types are Pulse Code Modulation (PCM) & Pulse Position Modulation (PPM). This pertains to how the signal is digitally modulated versus the radio frequency type of modulation, i.e. FM, frequency modulation or AM, amplitude modulation.

Early RC Txs use frequency modulation (FM) to provide signals from the Tx to the Rx. That puts them in the upper part (27MHz) of the High Frequency (HF) to the lower part (72 & 75 MHz) , of the Very High Frequency (VHF) spectrum. The upper part of the VHF band is used for air to ground and air to air voice communications and navigation. The newer ISM band 2.4GHz Txs use FM modulation as well but on a different frequency band from earlier models. They also use Pulse Code Modulation (PCM) to code the signal in order to take advantage of PCM over PPM.

(HF = 3MHz-29.9MHz)
(VHF = 30MHz-299.9MHz)

a.) PCM Signal Modulation
PCM or Pulse Code Modulation digitizes (1s & 0s) a FM signal. Your Rx decodes the signal. If noise is present, the Rx ignores it until it gets a good signal. It is looking for precise digital signals and ignores anything else. To use PCM you must have a computerized Tx.

b.) PPM Signal Modulation
PPM or pulse position modulation is an analogue signal with the signal length (transmission time equals length), or pulse width representing the data being sent. PPM was popular with the early CB radios but fell out of favor with the advent of PCM due to the ability to code, do error correction and create a failsafe setting. If one of your devices needs an analogue signal, and it is receiving a digital one (PCM), it will have to be decoded to an analogue signal (PPM) before it can be used.

A detailed explanation of PPM & PCM can be found here: http://adamone.rchomepage.com/guide1.htm#ppm

Just as AM gave way to FM, PPM has given way to PCM for signal modulation. But now instead of being on the CB (VHF) band, we have switched more and more to the 2.4GHz (UHF) band. Each manufacturer has a unique way to use error correction and coding the PCM signal. Since it is proprietary, you must use each manufacturer's proprietary Tx in combination with their proprietary Rxs. Some new manufacturers have decoded or broken the code and make Tx modules and Rxs that can use mimic or use a proprietary signal with their own equipment.

That is why you cannot use just any Tx with just any Rx or model you decide to buy.The Tx & Rx protocols must match.

NOTE:
This thread assumes you already know the differences between RTF, BNF, Tx-R, Rx-R, RR, ARF, KIT, PNP, PNF, etc and the implications for your Tx and Rx combinations. If not you may find my blog entry Some Basic beginner terms, Small & Medium battery connector types, links helpful.

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