Skip to content

Latest commit

 

History

History
70 lines (40 loc) · 3.74 KB

MTX.md

File metadata and controls

70 lines (40 loc) · 3.74 KB
Raw

mLRS Documentation: Setup for mTX

(back to main page)

This page describes how to set up a mLRS system for OpenTx radios running the mTX (formerly MAVLink for OpenTx) firmware.

Five steps need to be completed:

  1. The OpenTx radio needs to be flashed with the mTX firmware.
  2. The radio needs to be configured.
  3. The mLRS Tx module needs to be put into "mBridge mode".
  4. The mLRS system needs to be put into "MAVLink mode".
  5. The flight controller needs to be set up for MAVLink on a serial port.

Step 1. is beyond the scope of this article; please consult the project's discussion channels.

Note: An ArduPilot flight controller is assumed. For PX4 it needs to be tested and seen. INAV will not work AFAIK, as INAV is not a proper MAVLink component.

OpenTx/mTX Radio Setup

  • MDL->MODEL SETUP->External RF->Mode = mBridge

For more details on other possible configurations, please consult the mTX project discussion channels.

mLRS Tx Module Setup

  • Tx Ch Source = mbridge

The parameter "Tx Ser Dest" can be set to serial, serial2 or mbridge. If serial or serial2 is selected, then a MAVLink router is enabled which routes the messages between serial or serial2, the mTX radio, and the mLRS link. This allows you to connect a GCS to serial or serial2. If mbridge is selected, then the MAVLink router is not enabled and the MAVLink communication happens only between the mTX radio and the mLRS link.

Note: The parameter "Tx Snd RadioStat" should normally be set to off. There are situations in which it can be useful to enable "Tx Snd RadioStat", but you should do this only if you know what you are doing.

mLRS Receiver Setup

The configuration of the mLRS receiver can follow exactly the description in CRSF Telemetry and Yaapu Telemetry App: mLRS Rx Module Setup. The most important parameters to set are

  • Rx Ser Link Mode = mavlink (or mavlinkX)
  • Rx Snd RadioStat = ardu_1 (or meth_b)

It is possible to avoid the separate signal wire for the RC data, by sending the RC data via a MAVLink message to the flight controller. For this set:

  • Rx Snd RcChannel = rc override

Note: It is recommended to use the CRSF protocol for the RC data, since you get benefits like lower latency and better link statistics that are not available when sending the RC data via MAVLink.

ArduPilot Setup

MAVLink Serial Port

  • SERIALx_BAUD:
    • 57 for 31 Hz and 50 Hz modes
    • 38 for 19 Hz mode (57 works very well too, only parameter download is slower)
    • 230 for FLRC mode
  • SERIALx_PROTOCOL = 2 (important, do not use MAVLink v1!)
  • SERIALx_OPTIONS = 0

Note: 'x' refers to the serial port of your flight controller used for MAVLink

Stream Rates

In contrast to other setups, the SRy parameters for the stream rates do not need to be configured here (i.e., can be left at zero). The mTX firmware requests the required streams itself.

Only if the settings by the mTX firmware should be overruled, the SRy parameters can be configured as described in CRSF Telemetry and Yaapu Telemetry App: ArduPilot Setup.

Note: While the mTX radio is a full-fledged GCS in MAVLink terminology, it is not recognized by ArduPilot as its GCS, since the MY_GCS parameter is set by default to MissionPlanner/QGC. Accordingly, setting e.g. SERIALx_OPTIONS = 4096 has no effect on the stream for as long as no GCS is connected to serial/serial2 (or if Tx Ser Dest = mbridge is selected). If to set or not to set it in case of when a GCS is used, one may want to experiment with and choose what gives the best behavior.

CRSF Receiver

The configuration of the receiver settings in the ArduPilot flight controller can follow exactly the description in CRSF Telemetry and Yaapu Telemetry App: ArduPilot Setup.