Graupner SUMD

With Graupner HoTT radios you can use fully digital, single-line SUMD protocol. For the connection only normal servo cable is required.

1 Wiring

Connect the cable according the photo. In the unit the cable is in the RUD port. In the receiver it is always the last channel. For GR-12/GR-12L it is output with label "6". Please note that the signal wire (Orange) is at the bottom in the receiver.

If you have not connected a power supply, you can connect the BEC cable or 1-2S LiPol now (even without a servos). Never connect a power supply to the SYS or ELE/PIT/AIL ports!

2 Spirit Settings

After initialization of the unit you can start the software. To allow the connection set the Receiver type to SRXL/SUMD in the General tab.

Now save the settings (CTRL+S) or in the Backup tab/Unit - Save.

3 Receiver configuration

By default SUMD transmission is disabled in the HoTT receivers. It is necessary to enable it in the (F) Function/Telemetry/Setting & Data View menu. Change SUMD at CH6 to YES.

4 Usage

Now you can restart the unit. After the initialization the SUMD connection will work. Reverse of some channels might be necessary depending on the radio model - please check the Diagnostic tab.

The transmission is able to carry all the channels. Usualy SUMDOF12 option (if available) is enough.