RadioMaster ER8G Receiver User Manual

Introduction

The RadioMaster ER8G receiver is designed for glider pilots requiring a compact and slim receiver. It supports up to 8 servos and includes built-in receiver voltage telemetry and flight battery telemetry. The ER8G automatically detects which voltage input to use, allowing only one voltage input at a time. It features a dual-antenna system with telemetry power up to 100mW. Notably, the ER8G receiver does not have a built-in altimeter, making it suitable for competitions that prohibit vario usage or for users who do not require this feature. The ER8G can be powered by a 1S Lipo receiver battery.

Diagram Description: The ER8G receiver features a compact design with clearly labeled ports. The front view shows eight servo output channels (CH1-CH8), an EXT-V (external voltage) port, and a BOOT button. The side view indicates TX and RX connections. The top view highlights the receiver's dimensions (60mm length) and weight (12 grams). The back view shows the BATT (battery) connection. The antenna is 20cm long and located at the top. Power input is DC 3.5-8.4V.

TX & RX WIFI INFO: For configuration, the TX & RX WIFI INFO provides the network name (ExpressLRS TX), password (expresslrs), and access URL (http://10.0.0.1/) which can be opened in a browser.

Specifications

Firmware

Device Category: Radiomaster 2.4Ghz

Device: RadioMaster ER8G

Setup

Recommended ELRS LUA Settings

Voltage Input (EXT-V)

IMPORTANT: The maximum input voltage for the EXT-V (external voltage input) telemetry reading is 35V. Do not exceed this voltage, or the receiver may be damaged.

The external battery voltage is connected to the positive pole of the battery (typically welded to the positive pole of the ESC). Ensure the external voltage is not connected separately without also connecting to the BEC. The EXT-V connection is made via a solder pad on the PCB. A single wire must be soldered to this pad and connected to the positive wire of the battery or ESC. If no EXT-V power source is detected, the ER8G will default to reading the voltage on the receiver pins. Only one voltage input can be used at any given time.

For optimal performance with high-voltage, high-torque servos, it is recommended to use a 2S 7.4V battery for direct power or a suitable high-current UBEC.

Telemetry Calibration

Calibration of the telemetry voltage is required on your radio. Navigate to the TELEMETRY page on your radio, locate the RxBt sensor, and edit its settings. Adjust the offset until the displayed reading matches the actual battery voltage in the model. If a significant difference persists, adjusting the ratio may also be necessary. For best results, calibrate the voltage using a fully charged battery of the correct cell count intended for use in the model.

Channel 5 Usage for ExpressLRS Arming

ExpressLRS requires Channel 5 (CH5) to set the arming state of the RF module in your radio. It is recommended to assign CH5 to a switch, such as your throttle cut switch, for benefits like dynamic power. You can assign different channels to the CH5 output of your receiver using the ExpressLRS LUA or the Wifi WebUI.

For more information on the importance of setting up arming, please visit: https://www.expresslrs.org/

Power Input Channels

Channel 6 (CH6) on the receiver must not be used as a power input channel; it can only be used as a servo output channel. Power from an ESC or receiver battery must only be applied to Channels 1 through 5.

Binding Procedures

Passphrase Binding

Note: Bind phrases are not secret and can be read.

1. Open the ExpressLRS LUA script and navigate to the Wifi Connectivity page. Select the "Enable WIFI" option. Connect to your radio's Wi-Fi using a mobile phone, tablet, or PC (refer to TX WIFI info above). Open the ExpressLRS web page at http://10.0.0.1/ and choose a unique bind phrase. Save and reboot.
2. Power on the receiver and wait approximately 60 seconds for the LED to blink rapidly, indicating WIFI mode. Connect your phone, tablet, or PC to the receiver's WIFI (refer to RX WIFI info above). Open the ExpressLRS web page at http://10.0.0.1/ and enter the same bind phrase previously entered on your radio. Save and reboot. Once both the radio and receiver have the same bind phrase set, they will automatically bind.

Traditional Binding

1. When powering on the receiver for the first time, the LED will perform a quick double blink, indicating it is in bind mode. If this is not the case, hold down the boot button for 10 seconds to reset the receiver.
2. Power on your transmitter/radio and use the [BIND] button on the ExpressLRS Lua script, which sends out a binding pulse.
3. If the receiver has a solid light, it is bound!

Note: To bind the receiver a second time or to another radio, power cycle the receiver 3 times. On the third power cycle, the LED will double blink, indicating bind mode. If you cannot successfully enter bind mode using the 3 power cycle method, you can hold down the boot button for 10 seconds to reset the receiver to bind mode, or use the passphrase method.

WARNING: All previous settings in the receiver will be erased and need to be re-entered when using the reset button.

Example ELRS Lua Configuration Screen

The following shows an example of how the ELRS Lua script might appear on a radio for configuration and telemetry monitoring:

• Recommended: ELRS Lua
• Radio Model: RM Boxer
• Packet Rate: 100Hz Full
• Telem Ratio: Std (1:32)
• Switch Mode: 8ch
• Model Match: Off (ID: 0)
• TX Power: 250mW
• VTX Administrator
• HiFi Connectivity

Calibration: Telemetry

• TELEMETRY
• 8: TRSS -20dB
• 9: TQ1 100%
• 10: TSNR 15dB
• 11: RxBt. 7.40V
• 12: Curr 0.09A
• 13: Capa 0mAh
• 18 Bat.% 0.3%

Calibration: Sensors

• CH1: CH1
• CH2: CH2
• CH3: CH3
• CH4: CH4
• CH5: CH9
• CH6: CH6
• CH7: CH7
• CH8: CH8

2 Bind

• RM Boxer
• Type: Custom
• ID: 0008 1
• Source: Ext. module
• Unit: Backpack
• Ratio: [----EXIT----]
• Offset: -1.0