Accessing an extra channel on your heli's mini VBar flybarless controller is actually pretty simple. Just follow these instructions carefully.
First off, please note the following:
- Remember that unlike the other sockets, RXA is a triple input/output socket, so NEVER CONNECT POWER TO RXA. (The middle wire of the plug, from the ESC, for example, has the BEC voltage of 5 to 6 volts on it. Plugging that into RXA could damage your mini VBar flybarless controller.)
- You only get the signal from the bottom pin of RXA. You must get the power (+ and - voltages) from another socket, such as RXB or RXC. (Happily, you connect the phase sensor for the governor to the upper pin of RXA, so you can have both an extra channel and the governor.)
- You set which channel appears on the RXA signal wire by specifying the value of register 216 in the .vbr file, which looks like this:
<VALUE Register="216" Value="5"/>
Because computers (and mini VBar flybarless units, apparently) start counting at 0 instead of 1, the values are offset from the channel numbers by 1:
ESC/Throttle channel ---- 1 Register 216 value: 0
Aileron channel ----------- 2 Register 216 value: 1
Elevator channel --------- 3 Register 216 value: 2
Tail channel --------------- 4 Register 216 value: 3
Aux/Gyro channel -------- 5 Register 216 value: 4
Collective channel -------- 6 Register 216 value: 5
Channel -------------------- 7 Register 216 value: 6
Channel -------------------- 8 Register 216 value: 7
Channel -------------------- 9 Register 216 value: 8
Changing a registry value is as simple as typing in a new number in place of the old number, but be careful that that's the ONLY change that you make!
WARNING: If you are not comfortable editing computer configuration files, either don't do this or get some help. If you accidentally mess up your .vbr file, you can introduce unwanted changes to your heli's behavior (and worse, the changes may not be immediately obvious).
To change the value of register 216:
1. Connect your heli to your computer with the VStabi software running as usual (with the motor disconnected).
2. IMPORTANT: Save a backup copy of your current settings by clicking Save and saving the file as something like known_good_backup.vbr.
3. Save a second copy of the settings with a name like, new_register_216_value.vbr.
4. Open the second .vbr file in Notepad or the text editor of your choice.
NOTE: You must open the file in a simple text editor and not a word processor like Microsoft word.
5. Change the value of register 216 to the value you want. To get the correct value for register 216, subtract 1 from the channel number. For example, to assign Channel 7 to the bottom pin of the RXA socket, change the vaule or register 216 to "6": <VALUE Register="216" Value="6"/>
6. Save the the file (making sure it retains its .vbr file extension).
7. In the VStabi sofware, click Load and select your modified .vbr file. In the Which parameters groups? dialog box, click Select all, then click OK.
The new register value is uploaded to mini VBar, changing the channel output assigned to the RXA signal pin.
If you ever want to revert to your original, known-good VBar configuration, just load your backup file. (You could also just do a fresh setup, of course).
To connect a servo that uses the extra channel:
1. Get the signal from the bottom pin of RXA.
2. Get + voltage (red wire) from the center pin of RXB or RXC, and - voltage (black or brown wire) from the top pin of RXB or RXC.
Go slow, be careful and methodical, test to make sure everything's working right, and have fun.
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