Spektrum SRXL2 guide for OMP Hobby M2 V3 Helicopter / OFS3 / NX8

This guide will explain how to connect a Spektrum SRXL2 receiver to the OMPHobby M2 V3 helicopter. It will also provide instructions to configure a Spektrum NX8+ and get telemetry support.

Firmware Update

SRXL2 receiver protocol and telemetry support was added to OFS3 Flight controller since firmware version 14.70.

Please download the latest OFS3 Firmware from OMPHobby.com. Update the OFS3 Flight controller firmware using the OMPHobby OFS3 Bluetooth Module and the OMPHobby App on iOS/Android.

Compatible Receivers

Although any SRXL2 receiver will work a small and lightweight receiver is preferable for the M2 V3 Helicopter.

The SPM4650C und SPM4651T are the best options.

Spektrum SRXL2 DSMX Receiver with Connector Installed SPM4650C — SPM4650C

Connecting to the OFS3 Controller

The SRXL2 receiver needs to be connected to the CRSF port on the OFS3 controller. The connector that comes with the receivers is not suitable for connecting to the CRSF port. The Spektrum SRXL2 to OMP M2 V3 OFS3 receiver connection cable will be required. It connects to SRXL2 port on the receiver side and the CRSF port on the OFS3 Controller.

Spektrum SRXL2 to OMP M2 V3 OFS3 receiver connection cable

Connect one end of cable to the SRXL2 port on the receiver

Connect other end of the cable to the CRSF port on the OFS3 Controller

Configuring the Spektrum Transmitter

In this guide we be using the Spektrum NX8+ transmitter. The instructions should apply for any recent Spektrum transmitter.

Loading the Model Configuration

Download OMP M2 V3 Model Configuration for NX8+
Extract the zip file to locate the OH-M2-V3.NSPM file.
Import the model file into the NX8 Transmitter.

Power ON the transmitter, enter the system menu > USB storage
Connect a Micro USB cable to your PC and the micro USB connector on the back of the transmitter.
Select Access Internal Storage. The NX8+ will connect to your PC. A storage drive will show up for the NX8+
Copy the file to the NX8+ Storage drive.
Press the Back button or the roller to exit.
Disconnect the USB cable from your transmitter.
Go to System Menu > Transfer SD Card
Category: Model Import / Export
SD Card: Internal
Options: Import Model
Select File: OH-M2-V3.NSPM
Import Mode: Import
Select OH-M2-V3.NSPM Model File.
Now M2-V3 should be the active model.

Switch Function Mapping

Function	Switch
Timer reset	A (Timer Resets only when in Throttle Cut)
Throttle Cut	F
Flight mode (Normal, Stunt-1, Stunt-2) & SWRPM on Channel 7 (GOV)	B
Attitude hold (auto level) (OFF, ON, ON)	D
Dual Rates (100% / 85% / 75%)	G

Spektrum NX8+ Switch Assignment

Throttle Curves

The configuration contains following throttle curves

Normal mode: 0-60-60-60-60 (3600 RPM)
Stunt 1: 65-65-65-65 (3900 RPM)
Stunt 2: 70-70-70-70 (4200 RPM)

Binding to Helicopter

It is recommended to remove main and tail rotor blades to prevent injury if motor starts accidentally.

Press and hold the Bind button on the receiver while powering up the Helicopter.
The Orange LED on the Receiver will be flashing indicating that it is ready to bind.
On the Transmitter, ensure Throttle cut is active and then go to Model Function List->Bind. Press BIND.
When binding completes the Orange LED on the receiver will be steady.

Pre-Flight checks

Check swash plate moves in correct direction for aileron, elevator and collective pitch stick movements.
Check motors turn on when throttle cut is removed and throttle stick is increased.
Check motors turn off when throttle cut is active.
Install main and tail rotor blades.

Telemetry

Use the roller to scroll through telemetry screens. The following information is available

Battery Consumption (capacity)
Battery Current
Rotor RPM
Battery Voltage

A vibration and sound warning is set when battery capacity reaches 550mAh.

Flight Timer

Flight timer is set to 5:00 minutes. The Flight timer can be reset when changing battery pack by ensuring throttle cut is active and then activating Timer reset switch.