FrSky TW SR8 Dual 2.4G Receivers Instruction Manual

FrSky TW SR8 Dual 2.4G Receivers

Product Information

Specifications

• Frequency : Dual 2.4GHz
• Dimension : 542010mm (LWH)
• Weight : 9.8g
• Operating Voltage : 3.5-10V (Please ensure the supplied voltage exceeds 2.8V during use.)
• Operating Current : 80mA@5V
• Voltage Measurement Range via AIN2 (External device): 0-36V
• Antenna Connector: IPEX4
• Compatibility : TWIN series Radio & RF module in TW mode

Features

• Simultaneous working dual 2.4G TW mode
• Built-in Advanced Stabilization Functions
• Built-in High-Precision Telemetry Sensor (Altitude, Vertical Speed, etc.)
• Black-Box function
• Long control range (Range varies based on the RF Power settings.)
• Over-The-Air (OTA) FW update
• 8 PWM channel ports
• SBUS Out port (Supports 16CH / 24CH mode)
• SBUS In port (Supports Signal Redundancy)
• FBUS / S.Port

Overview

• Dimensions: 54mm x 20mm x 10mm
• The TW SR8 receiver features a new stable TW protocol that integrates dual active 2.4G frequency bands simultaneously. This active-active protocol allows both 2.4G frequency bands to be active at the same time, providing enhanced signal control and redundancy.
• The receiver is equipped with 2×2.4G antennas and supports SBUS In & Out channel and 8 PWM output channel ports. It also supports telemetry functions through FBUS / S.Port, allowing bidirectional transmission and simplifying model build with fewer wires.

Product Usage Instructions

LED State

• Green LED (LoRa): On
• Blue LED (FSK): Off
• Red LED: On
• Yellow LED (Calibration of Accelerometer): Flashing
• Yellow LED (Self-check): Off

Registration & Automatic Binding

1. Enter the Model menu and select RF System.
2. Turn on the internal module and select status [ON] and TW MODE (Type).
3. Select [Register].
4. Connect the battery to the receiver while holding the button on the receiver. The RED LED and GREEN LED on the receiver will be on, indicating the [Reg] status.
5. When it shows the Register ID, RX name, and UID, click [Register]. The RED LED and GREEN LED on the receiver will indicate successful binding.

FAQ

1. Q: What is the operating voltage range for the TW SR8 receiver?
   A: The operating voltage range for the TW SR8 receiver is 3.5-10V. Please ensure the supplied voltage exceeds 2.8V during use.

2. Q: What is the weight of the TW SR8 receiver?
   A: The weight of the TW SR8 receiver is 9.8g.

3. Q: What is the compatibility of the TW SR8 receiver?
   A: The TW SR8 receiver is compatible with TWIN series Radio & RF module in TW mode.

4. Q: How many PWM channel ports does the TW SR8 receiver have?
   A: The TW SR8 receiver has 8 PWM channel ports.

Instruction Manual for TW SR8 Dual 2.4G Receivers

Introduction

• TWIN series TW SR8 receiver features a new stable TW protocol that benefits from simultaneously integrating dual active 2.4G frequency bands. The TW active-active protocol is different from the general active-standby redundancy solutions (where one receiver takes over signal control only when the other is in Failsafe mode), with the TW protocol, dual 2.4G frequency bands are active on the
• TW series receiver at the same time.
• The TW SR8 receiver is equipped with 2×2.4G antennas. The signal ports include both SBUS In & Out channel and 8 PWM output channel ports. It also supports telemetry functions through FBUS /S.Port. By setting the TW SR8 to use FBUS protocol in the ETHOS system, the signal control and telemetry can be connected to any device that supports FBUS protocol through only one line to achieve bidirectional transmission, also simplifying the model build using fewer wires.

ADV Stabilizer

• The TW SR8 offers an ADV Stabilizer function which is an upgrade over the original classical gyroscope stabilization modes. The ADV Stabilizer offers an advanced mode that provides more programmable stabilized channels and flexibility.
• The classical stabilization mode has been enhanced with 5 additional stabilization channels, providing pin mapping to each channel in the multiple flight modes like Stabilization, Auto-Level, Hover, and Knife-Edge with an airplane model.
• In the advanced stabilization mode, all the output pins are configurable for stabilization and additional advanced features such as Stab file sharing, programmable parameters, developer access, etc.
• The advanced stabilizer feature incorporates high-precision telemetry sensors to monitor altitude, vertical speed, etc. This ADV feature is an additional benefit compared to using a regular S series stabilization receiver.

Overview

Specifications

• Frequency : Dual 2.4GHz
• Dimension : 542010mm (LWH)
• Weight : 9.8g
• Operating Voltage : 3.5-10V (Please ensure the supplied voltage exceeds 2.8V during the use.)
• Operating Current : 80mA@5V
• Voltage Measurement Range via AIN2 (External device): 0-36V
• Antenna Connector : IPEX4
• Compatibility : TWIN series Radio & RF module in TW mode.

Features

• Simultaneous working dual 2.4G TW mode
• Built-in Advanced Stabilization Functions
• Built-in High-Precision Telemetry Sensor (Altitude, Vertical Speed, etc.)
• Black-Box function
• Long control range (Range varies based on the RF Power settings.)
• Over-The-Air (OTA) FW update
• 8 PWM channel ports
• SBUS Out port (Supports 16CH / 24CH mode)
• SBUS In port (Supports Signal Redundancy)
• FBUS / S.Port

LED State

Registration & Automatic Binding

Follow the step below to finish the registration & binding procedure:

1. For TWIN X14 as an example, enter into the Model, select RF System, turn on the internal module, select status [ON] and TW MODE (Type), then select [Register].
2. Connect the battery to the receiver while holding the button on the receiver. The RED LED and GREEN LED on the receiver will be on, indicating into the [Reg] status.
3. When it shows the Register ID, RX name and UID, click [Register]. The RED LED and GREEN LED on the receiver will flash, and the transmitter displays [Registration OK ].
4. Power off the receiver.
5. Move the cursor to select any one of the 3 receivers and press [Bind].
6. Connect the battery to the receiver.
7. Select the RX, the GREEN and BLUE LED will keep lit, then the transmitter displays [Bind successful].
   Note: Once the receiver is registered, the button is not needed anymore in the binding process.

IMU Mode

Note: Please move to the [DOWNLOAD] section from the product page to download the functional Lua scripts of Stabilization (Place the decompressed folder in the root directory of the [Scripts] folder on the memory card to use.)

The devices with ADV features offers three modes below to setup the stabilization module.

• OFF mode : The stabilization module is not activated in the mode.
• BASIC mode : The mode is enabled by default can do the basic configurations directly on radio.
• ADV : The mode supports full configuration of stabilization mode with RBmixer programmer on PC.
  Note : Selecting the BASIC mode for the normal stabilization usages. For accessing more flexiablities of

Set the IMU mode to ADV mode and change the ADV config option from Disable to Enable, which supports parameter setting for ADV self-stabilizing mode through the Upgrade/S.Port interface.

• Note : If you do not use the ADV advanced self- stabilizing mode of the receiver, this option  must be kept disabled.
• Please ensure the [ADV config] is set to Disable from the SRX Basic script before the flight.

CaliHorizontal Function

Enable the CaliHorizontal mode can do the calibration for the horizontal plane.

Note: This “CaliHorizontal” function is only activated for ADV mode horizontal calibration. It doesn’t work while using the basic mode.

Two independent stabilizing functions

1. Option 1: The “Stable System 1” allows turning on/off the first group of stabilization channels (CH1-6);
2. Option 2: The “Stable System 2” allows turning on/off the second group of stabilization channels (CH7-11);.

Note : Pressing the center button of the left navigation menu buttons, users can switch  to the second configuration page of stabilization channels.

Note : The settings for Stable System 1 and 2 are independent, Stab calibration and self-check should be completed for both stab systems.

Basic Step Guides-Stabilization Function

• Model Creation & Make sure the connected receiver is bound to the radio;
• Ensure stabilization is enabled & Calibrate the gyroscope sensor of the device;
• Servo connection & Build the stabilization device to the model;
• Set up the mixer channel and radio switches;
• Determine the [Wing Type] & [Mounting Type];
• Check the stabilized channel outputs of the receiver in the Auto-Level mode;
• Check the stick control of the transmitter in the manual mode;
• Self-Check of the receiver;
• Failsafe setting.

Gyroscope Sensor Calibration

Ensure the TW SR8 stabilization function is enabled.

•  [System] → [SRX Stable]
• [SRX Stable] → [Stabilizing] → [On]

Move to [SRX Calibration] tool and calibrate the gyroscope sensor

1.  The gyroscope of device (6 surfaces) must be calibrated before mounting into the model. Please place the device on a flat ground or a table, and follow the instruction steps below to calibrate the gyrosope sensor;
2. Make sure the stabilization device with the Logo label side facing upwards laying on the desktop, move to the radio and enter the [SRX Calibration] tool, and select “click to confirm”. At this moment, the yellow LED light will flash until it lits off, then follow the prompts to calibrate the sensor;
3. Complete the calibration of all the device surfaces. Ensure the values of each axis (X, Y, Z, Mod) is about 1.000 while placing the device in the corresponding direction, and the deviation could be within ±0.1;
4. The calibration is completed if all the steps above are done.

Servo connection & Build the device to the model

Connect the servos to the ports of the stabilization device according to the Channel List.
Note: Please make sure the 4-pin Port forwards the nose direction of airplane model.

• Gyro gain adjustment of CH13: When the the value of CH13 is in the center, the gain is zero. The gain increases as the value get bigger. Until the value is ±100%, the gain reaches maximum.
• Attentions
  • CH1~CH12 should be connected to the corresponding servos.
• Set up the mixer channel and radio switches

Refer to the Channel List to set the channel and switches. The switch setting of CH13-15 on the picture is for reference.

Move to the [SRX Stable] tool, determine the [WinG Type] & [Mounting Type];

1. Wing Type
2. Mounting Type

[Gain] and [Offset] configurations of flight modes

1.  Gain – Stab Mode Gain
2. Auto-Level Mode
3. Gain – Hover Mode

1.  Gain – Knife Mode
2. Angle Offset
3. Auto-Level Mode
4. Angle Offset – Hover Mode
5. Angle Offset – Knife Mode

Check whether the reaction of the wing servo is in line with the flight attitude caption below in the [Auto-Level] mode. If not, please try to invert the corresponding channel output in the [SRX Stable] tool.

Inspection of flight attitude
To ensure flight safety, checking the compensation direction of the model is strongly recommended. Activating auto level mode will produce a strong deflection on AIL and ELE, which is used to check the response of aileron and elevator. Also, activating Knife-edge and Hover mode will have the same reaction on the rudder.

• When the plane is rotated left or right (Roll), ailerons should have the correcting actions as illustrated.
• When the plane is rotated up or down (Pitch), elevators should have the correcting actions as illustrated.
• When the plane is rotated to left or right (Yaw), rudders should have the correcting actions as illustrated.

After changing the compensation direction, make sure to check it again on the actual model.

Note: If the compensation direction is incorrect, please reverse the corresponding channel as illustrated  above through the [SRX Stable] tool.
Check whether the reaction of the wing servo is in line with the radio stick operation in the [Manual] mode. If not, please try to invert the corresponding channel output by pressing the channel bar in the [Output] tool.

Self Check

1. Make sure the model is in a horizontal position on the ground, then put the throttle to 0, and keep the other channels in the center position.
2. Move to [System] and enter the [SRX Stable] tool to turn on [Self Check], then the blue LED light turns on. Once the blue LED starts flashing, we can calibrate the maximum travel of stick channels (excluding the throttle channel).
3. If the calibration is completed, the LED turns off and the servos react left and right to indicate that the calibration process is completed.

•  Do the Self-Check in the [SRX Stable] tool.
• [System] → [SRX Stable] → [Self-Check]

Note : To do the Self-Check of the stabilization device, please ensure the stabilization function is enabled. Enter the [SRX Stable] tool and turn On the [Stabilizing], then quit the [SRX Stable] tool and back into this tool again, now the [Self-Check] function is capable to enable.

How to set the flight modes

Quick Mode
It supports stabilization mode, auto-level mode, and manual (Gyroscope is off) mode and configured through CH14. Note: The default mode of TD SR8 is Quick Mode.

• If Quick Mode is applied, there is no Knife Edge or (3D) Hover Mode.
•  CH15 is not used when using Quick Mode.

Enable the Quick Mode in the [SRX Stable] tool.

Conventional Mode
It supports stabilization mode and manual (Gyroscope is off) mode and configured through CH14&15. The precise configuration is Written below.

Model Configuration Reference

Conventional Model

Flight mode| Stabilization| Automatic level| Hover| Knife- Edge| Off
---|---|---|---|---|---
CH14 (3 pos SW)| CH14>M+H (CH14 SW Down)| CH14>M+H (CH14 SW Down)| CH14>M+H (CH14 SW Down)| CH14<M-H (CH14 SW Up)| CH14 SW-Mid
CH15 (3 pos SW)| M-H<CH15<M+H (CH15 SW Mid)| CH15>M+H (CH15 SW Down)| CH15<M-H (CH15 SW Up)| M-H<CH15<M+H (CH15 SW Mid)

Note :

• M: represents a neutral signal period (1500μs)
• H: represents the time of required signal change to activate the mode (50μs). When the factory settings are selected, the switch position shown above represents the required modes.

Delta wing & Flying wing & V-tail

• Layout of Delta wing / Flying wing
• The available flight modes can be assigned to CH14 with a three-position switch.

1. When Delta wing/Flying wing is selected, the signal produced by the transmitter should be without active mixes on the channels related to AIL and ELE. TW SR8 will mix the AIL (CH1) and ELE (CH2) input signal with a fixed mix percentage automatically.
2. When V-tail type is selected, the signal produced by the transmitter should be without active mixes on the channels related to ELE and RUD. TW SR8 will mix the ELE (CH2) and RUD (CH4) input signal with a fixed mix percentage automatically.
   • Stabilization: When the model is activated, TW SR8 will compensate with external forces (wind) as soon as receiving commands from the transmitter. This function is used to enhance the stability of the model on three axis (Pitch, Roll, YAW). CH13 could be used to adjust gyro gain by assigning a knob or a slider, changing the sensitivity of the counteracting signal produced by the internal three-axis gyroscope.
   • Automatic level: When the mode is activated, TW SR8 will make the model return to level orientation with internal three-axis accelerometer and three-axis gyroscope on AIL and ELE channels after the sticks being released to neutral. RUD channel works in stabilization mode only.
   • Hover: When the mode is activated, TW SR8 will make the nose of the model straight up with internal three-axis accelerometer and three-axis gyroscope on RUD and ELE channels (ELE and RUD inputs are not required). Under this mode, AIL is used to control the rotation of the model and THR adjust the altitude. AIL channel works in stabilization mode only.
   • Knife-edge mode: When the mode is activated, TW SR8 will roll the plane on a certain side (wing points up) with internal three-axis accelerometer and three-axis gyroscope on RUD and AIL channels. Thus, AIL inputs are not required. While the mode steering is done with ELE, altitude will be maintained with THR/RUD. ELE channel operates in stabilization mode only.
   • Off: When the mode is activated, TW SR8 will transmit the received commands produced by the transmitter to the model without compensating.

Configuration for the Movement Range of the Roll and Pitch Angle in Stab Mode

• Make sure the [SRX Stable] script tool has been downloaded and placed in the [Scripts] folder of the storage card. The tool can be found under the [System] menu page after rebooting the ETHOS system.
• Ensure the receiver is bound to the radio and its Stab data is readable through Lua script. The movement angle of Roll and Pitch for Stab mode can be configured up to 80 degrees.
• This feature will not be activated if the degree value is set to 0-9. The setting with the Roll/Pitch degree between 10 to 80 can have the feature work, and it’s not recommended to be set with the degree values too small.

How to Switch High PWM Speed mode

1. The factory default setting is OFF .
2. To go to the receiver [Options], select On to active high speed mode .
   Warning: High PWM speed mode is only applied for digital servos. Turn off High PWM Speed mode

How to switch the S.Port/F.Port/FBUS

• Enter into RX Settings.
• Click [SBUS], then select SBUS-16 mode or SBUS-24 mode.

Black Box

• Black box records flight data, e.g, RX Reset Case, RSSI, VFR and so on. For TANDEM X20 as an example, to get flight data, please go to RF System-[Set]-[Flight Data Record].

About OTA function

• Go to the [File manager], and select the FW, press the enter button, select [Flash RX by int. OTA]. Power on the receiver, select the RX, go to the [ENTER], complete the flash process, the transmitter will display [Success]. Wait for 3 seconds, the receiver works properly at the moment.
• Note : Please do not do the binding operation in the near range while the firmware upgrading in progress.
• Note : Update the firmware after the receiver getting registered (OTA).

Range Check
A pre-flight range check should be done before every flight, in case the signal loss is caused by the reflection of the signal by the nearby metal fence or concrete, and the shading of the signal by buildings or trees during the actual flight.

1.  Place the model at least 60 cm (2 feet) above the non-metal contaminated ground (such as on a wooden bench). The receiving antenna should be in a vertical position.
2. Ener the ETHOS system, move to the “RF System”, scroll the Encoder to select “RANGE” mode and press Encoder. In range check mode, the effective distance will be decreased to 1/30.

How to set Failsafe

There are 3 failsafe modes when the setting is enabled: No Pulse, Hold, and Custom mode.

• No Pulses Mode: On loss of signal, the receiver produces no pulses on any p.m. channel. To use this mode, select it in the menu and wait 9 seconds for the failsafe to take effect.
• Hold Mode : The receiver continues to output the last positions before the signal was lost. To use this mode, select it in the menu and wait 9 seconds for the failsafe to take effect.
• Custom Mode: Pre-set to required positions on the lost signal. Move the cursor to the failsafe mode of the channel and press Encoder, then choose the Custom mode. Move the cursor to the channel you want to set failsafe On and press Encoder. Then rotate the Encoder to set your failsafe for each channel and short-press the Encoder to finish the setting. Wait 9 seconds for the failsafe to take effect.

Note:

• If the failsafe is not set, the model will always work with the last working status before the signal is lost. That could cause potential damage.
• When the failsafe is disabled on the RF module side, the receiver defaults to Hold mode.
• When in No Pulses Mode, do not set the Failsafe to No Pulses Mode for the SBUS port as it will keep the signal output continuously Please set “Hold” or “Custom” mode for the SBUS port.

FCC STATEMENT

1. This device complies with Part 15 of the FCC Rules. Operation is subject to the following two conditions:
2. This device may not cause harmful interference.
3. This device must accept any interference received, including interference that may cause undesired operation.
4. Changes or modifications not expressly approved by the party responsible for compliance could void the user’s authority to operate the equipment.

NOTE: This equipment has been tested and found to comply with the limits for a Class B digital device, pursuant to Part 15 of the FCC Rules. These limits are designed to provide reasonable protection against harmful interference in a residential installation. This equipment generates uses and can radiate transmitter frequency energy and, if not installed and used in accordance with the instructions, may cause harmful interference to transmitter communications. However, there is no guarantee that interference will not occur in a particular installation.

• If this equipment does cause harmful interference to transmitter or television reception, which can be determined by turning the equipment off and on, the user is encouraged to try to correct the interference by one or more of the following measures:
  • Reorient or relocate the receiving antenna.
  • Increase the separation between the equipment and receiver.
  • Connect the equipment into an outlet on a circuit different from that to which the receiver is connected.
  • Consult the dealer or an experienced transmitter/TV technician for help.

FrSky is continuously adding features and improvements to our products. To get the most from your product, please check the download section of the FrSky website www.frsky-rc.com for the latest update firmware and manuals

• FrSky Electronic Co., Ltd.
• www.frsky-rc.com
• Contact us : frsky@frsky-rc.com
• Add: F-4,Building C, Zhongxiu Technology Park, No.3 Yuanxi Road, Wuxi, 214125, Jiangsu, China
• Technical Support: sales4tech@gmail.com 

References

• Robinson+Cole
• FrSky Top Rated RC Hobby Radio, Receiver and RC Model - Lets you set the limits

Read User Manual Online (PDF format)

Read User Manual Online (PDF format)  >>

Download This Manual (PDF format)

Download this manual  >>