2 Axis setup with MX-20 GR-24

Discussion in 'Radian' started by Gary Haynes, Jan 10, 2013.

  1. Gary Haynes

    Gary Haynes Administrator
    Staff Member

    Joined:
    Jul 6, 2012
    Messages:
    5,211
    Likes Received:
    460
    Today I started to rebuild my crash and received my Radians. Now I have an MX-20/GR-24 question on how the Mode command works.

    Here's the setup

    1. I am using channel 11 on the GR-24 for the Mode command, one of the last channels I have available.
    2. The MX-20 has all of the switches used up so I setup the CTRL8 rotary knob to act as the switch.
    3. GR-24 Chan11 is connected to Port 2 on the Roll Radian. (There is a note in the software when you click on the Mode Channel to set it to 0 for PWM and plug into Input 2)
    4. On the Roll Radian port 3 goes to the Tilt Radian. I have also tried Port 1 and 2.

    Operationally this all works. After the initialization with the MX-20 CTRL8 outputting a -100 value the Roll servo wil stop running. But the Tilt servo continues to run and be active. When I rotate CTRL 8 to 0 or a positive number the Roll axis becomes active.

    So the question I have is why the Tilt access does not turn off the servo when the Mode is at 0?

    In the software I can also see the slider move with the inputs from CTRL8.
     
  2. Gary Haynes

    Gary Haynes Administrator
    Staff Member

    Joined:
    Jul 6, 2012
    Messages:
    5,211
    Likes Received:
    460
    Think I found the answer in another post that included a drawing of the Graupner setup. Need to use the CTRL8 signal to both the Tilt and Roll Radians. That should fix it up.
     
  3. Andy Johnson-Laird

    Andy Johnson-Laird Administrator
    Staff Member

    Joined:
    Jul 31, 2012
    Messages:
    10,366
    Likes Received:
    1,162
    Hi Gary:
    That will distribute the Mode control to both sensors.

    The thing I was thinking about was whether there was a simpler way -- but with the disclaimer that I have 3-Axis gimbals so the problem's never come up for me. I was wondering how best to get the PPM signal from the Flight Control board down to the Roll Radian (which is then designed to talk S.bus to the tilt Radian incidentally).

    I presume that the easiest way is to solder the GR-24 SUMO (channel 8) servo lead to the pads on the FC, and also solder a ground and PPM signal that goes out to a servo connector you connect up to port 1 of the Roll Radian? That would then get the Roll Radian access to the PPM signal. Then you could wire up a servo lead from Port 3 of the Roll Radian to Port 1 of the Tilt Radian.

    Just restating this:
    GR-24 --> FC (Gnd, +5, PPM), then take (Gnd, PPM) ---> Roll Radian, port 1.
    Then connect Roll Radian, port 3 to Tilt Radian, Port 1.

    EDIT: Note: I'm assuming that you're providing separate +5 to the Radians/Servos rather than driving them from the flight battery.

    Given that both Radians now see the PPM signal then you can configure them both to use channel 11 for Mode control, and, some other channel for Tilt slew control?

    Is this how you guys with the 2-Axis gimbals do it?

    Andy.
     
  4. Gary Haynes

    Gary Haynes Administrator
    Staff Member

    Joined:
    Jul 6, 2012
    Messages:
    5,211
    Likes Received:
    460
    Andy I did a q
     
  5. Gary Haynes

    Gary Haynes Administrator
    Staff Member

    Joined:
    Jul 6, 2012
    Messages:
    5,211
    Likes Received:
    460
    Andy

    That should work. As I rebuild I am going to go back to an MK stack with the I2C converter, similar to Josh's build, while I sort things out with the HF boards. Let you know how it works out.

    Only other solution would be to run a second receiver just fo the 2 axis gimbal. Wonder if anyone has tried running 2 receivers from one MX-20 and has any suggestions. Manual says you can do it but as usual a bit hard to follow.
     
  6. Andy Johnson-Laird

    Andy Johnson-Laird Administrator
    Staff Member

    Joined:
    Jul 31, 2012
    Messages:
    10,366
    Likes Received:
    1,162
    Hi Gary: The Receiver "manual" seems a little more clear for what you're trying to do. Here's what's in the GR-24 (and also in GR-16, I believe):

    2.1.1.Binding“ multiple receivers in one model
    If required, it is also possible to bind multiple receivers to the transmitter for a particular model. The fi rst
    step is to bind each receiver individually using the procedure already described.
    When the system is in use, the receiver which was bound last is the Master receiver. Any telemetry sensors
    installed in the model must be connected to this unit, as only the Master receiver transmits sensor
    data using the downlink channel. The second and all further receivers operate in parallel with the Master
    receiver but in Slave mode, with the downlink channel switched off.
    The control functions can also be distributed amongst multiple receivers; this is carried out using the
    Channel Mapping function of the SMART-BOX (Order No. 33700). In the same way it is possible to assign
    one control function to multiple receiver outputs; a typical example would be the use of two servos
    for each aileron instead of only one, etc.

    Hope this helps.
    Andy.
     
  7. Gary McCready

    Gary McCready Active Member

    Joined:
    Oct 26, 2012
    Messages:
    284
    Likes Received:
    42
    I'm a single operator with Graupner MX-20/Gr-24 also.
    So to control my Radian all I need is two wires from the MK FC, (PPM and Grd ) to the Radian? Ie: make "Y" cable from channel 8 Could I also just run two servo wires from one of the GR-24s other servo outputs (ie channel 1-6 reassigned), to the radiian?
    I will power the Radians from a BEC I already have on-board.
    I do have a three position switch available, and can reassign the rotary switch.
    Sorry I'm having trouble finding info about this subject, and wiring diagrams.
     
  8. Gary McCready

    Gary McCready Active Member

    Joined:
    Oct 26, 2012
    Messages:
    284
    Likes Received:
    42
  9. Andy Johnson-Laird

    Andy Johnson-Laird Administrator
    Staff Member

    Joined:
    Jul 31, 2012
    Messages:
    10,366
    Likes Received:
    1,162
  10. Gary McCready

    Gary McCready Active Member

    Joined:
    Oct 26, 2012
    Messages:
    284
    Likes Received:
    42
    Not exactly sure why you would want to turn off telemetry. Did iI miss something? I like knowing the voltage and signal strength.
     
  11. Andy Johnson-Laird

    Andy Johnson-Laird Administrator
    Staff Member

    Joined:
    Jul 31, 2012
    Messages:
    10,366
    Likes Received:
    1,162
    If you want to have two Graupner Rx on the same Cinestar with a 360 gimble, it works much better if only the one on the hub is sending telemetry. Then there is no conention between two Rx both trying to send telemetry.

    The advantage to this set up is that it makes it much easier to switch between a single operator (when you use both Graupner Rx from a single Tx), to a dual operator (you just fire up your Spektrum Tx and the Radians will give priority to a Spektrum Satellite plugged into the first Radian sensor.

    Andy.
     
  12. Gary McCready

    Gary McCready Active Member

    Joined:
    Oct 26, 2012
    Messages:
    284
    Likes Received:
    42
    Thanks Andy. I think that you only get telemetry from one unit if two Rx are connected, manual:"the receiver which was bound last is the Master receiver. Any telemetry sensors installed in the model must be connected to this unit, as only the Master receiver transmits sensor data using the downlink channel."
    Of course, just because it is in the manual doesn't mean it won't cause problems. Glitches can abound when we try something not "standard". I had a throttle "off" takeoff and crash, when I armed my MK in what I think was the MX-20's "range test".

    I do have a DX-8/spetrum too, and was going to hook this up as a secondary, after the get the first one dialed in. I think it will work with only one GR-24 too. I think the guys at Quadrocopter have done this.

    Follow-up: I did get feedback from Freefly and Quadrocopter: They both suggested NOT splitting the SUM channel 8 signal going to the MK FC, but running servo wires from the other channels outputs.
     
  13. Gary McCready

    Gary McCready Active Member

    Joined:
    Oct 26, 2012
    Messages:
    284
    Likes Received:
    42
    Wanted to THANK YOU guys for helping me! I got my Radians all setup and working. It was suggest that I run servo wires from 9&10 channels on my GR-24 Rx, rather than split the SUM signal (on channel 8) going to the Mikrokopter FC board.
    I have my channel 9 turning on and off the Radians, and channel 10 on a dial for tilt.
     
  14. Andy Johnson-Laird

    Andy Johnson-Laird Administrator
    Staff Member

    Joined:
    Jul 31, 2012
    Messages:
    10,366
    Likes Received:
    1,162
    Gary: Glad to hear that you got it sorted out.
    Andy.
     

Share This Page