Table of Contents
1. Product Introduction
1.1 Product Introduction and Parameters
VM31 is mesh radio developed based on LTE, OFDM, MIMO. With dual 10/100 Ethernet and serial gateway functions, it provides reliable wireless Ethernet bridge functions and gateway services for most devices. VM31 combines smooth integration with 3-in-1 (video, telemetry, RC) link for a faster, more cost-effective path to system fielding. There are 3 frequencies for choice, 800MHz, 1.4GHz and 2.4GHz. Parameters are as below: It features compact size, high integration, high sensitivity, which provides great convenience for the user.
Item | Parameters | Description |
Frequency | 800MHz 1.4GHz | 806~826MHz 1427.9~ 1467.9MHz |
RF power | -40 – 25dBm | Adjustable |
Transmission range | 10KM | LOS |
S-BUS port | 2 S-BUS | NA |
Serial port | 1 channel | Simplex, baud rate adjustable |
Latency | 200-300ms | |
Power supply voltage | 7.4 – 24V | NA |
Bandwidth | 1.4M – 20M | 1.4M\3M\5M\10M\20M |
Video input/output | LAN | Connecting IPC or PC |
Range ofbands andfrequency pointsfor eachfrequency band ofthe module.
Frequency band | Frequency range | Frequency point range |
800MHz | 806~826MHz | 8060-8260 |
1.4GHz | 1427.9-1467.9MHz | 14279- 146790 |
1.2 Antenna mounting intent
1. Keep the antenna tightly with the SMA interface;
2. Keep the antenna on the AIR side uncovered, and straight up, or straight down;
3. Keep the antenna on the GND side uncovered, and parallel with the one on the AIR side;
4. Keep metal objects away from the antenna to avoid the communication loss;
5. Use the antenna with high quality;
6. May adjust the antenna’s angle to improve the signal strength;
1.3 Indicators And Interfaces Instruction
①RX Data receiving indicator: light will flicker in the condition of data receiving.
② TX Data transmitting indicator: light will flicker in the condition of data transmitting.
③ LINK RF link connection indicator: When this node is added to the network, the
indicator is steady on.
④ BAND Frequency indicator light: showing the current frequency. Green light indicates
800MHz; red light indicates 1.4GHz and yellow light indicates 2.4GHz.
⑤ POWER supply indicator: indicating power supply status. Steady ON in the
normal power supply status.
⑥ SET button: used for firmware upgrading, serial port baud rate setting, fail-safe settings
Side
① TTL port: serial port
② S-BUS1port: SBUS input(ground unit);SBUS output(airborne unit)
③ S-BUS2 port: SBUS input(ground unit);SBUS output(airborne unit)
④ Power supply port: 7.4-24V
⑤ TTL signal indicator: light will flicker when there is data input
⑥ SBUS1 indicator:
- Ground unit: SBUS1 indicator will flicker when there is data input of SBUS1.
- Airborne unit: SBUS1 indicator will flicker when there is data output of SBUS1.
⑦ SBUS2 indicator:
- Ground unit: SBUS2 indicator will flicker when there is data input of SBUS2.
- Airborne unit: SBUS2 indicator will flicker when there is data output of SBUS2.
LAN port: for video input or output
USB port: debugging interface. After the driver is installed, a virtual NIC can be used
2. Item List
2.1 Main Module
2.2 Accessories
3. Product Use
3.1 Preparation
Power on the airborne unit and ground unit. After the successful connection of the two modules (signal indicator is steady, this process takes about 1 minute), the device can work normally, and all parameters have been configured well. If you want to modify the baud rate of the serial port and the IP address of the network port, please refer to the corresponding steps.
Note! The products are factory configured and ready for use. Default configuration parameters.
User name: admin123
Password: admin123
LAN port IP: 192.168.168.12 (airborne unit); 192.168.168. 11(ground unit)
Secret key: 1000
Wireless parameters: frequency: 1.4G; frequency hopping mode: start; bandwidth: 10M;
power: 25dbm
Serial port parameters: baud rate: 115200; 8 data bits; 1 stop bit; no parity;
3.2 Serial Port Operation
The default baud rate of the serial port is 115200. Pls follow the below methods to connect the flight control and ground station software.
1. Connect flight control to the airborne unit. Pls kindly be noted the line sequence and the baud rate of the flight control port must be the same as the baud rate of the serial port.
2. Connect the ground station software to the ground unit. Pls kindly be noted that the line sequence and the baud rate of the port selected by the ground station software must be the same as the baud rate of the serial port.
Serial port baud rate change
After power-on, long press the SET key (about 2 seconds). When TX and RX light up at the same time and release it, it indicates the module entering baud rate change state. Short press the SET key (<1 second) to switch the corresponding baud rate.
Indicator status | Baud rate |
Rx continuously ON | 9600bps |
Tx continuously ON | 19200bps |
LINK continuously ON | 38400bps |
BAND continuously ON | 57600bps |
POWER continuously ON | 115200bps |
After finishing the setting, long press the SET key (about 2 seconds). When TX and RX light up at the same time, pls release the key. After releasing, the indicator will return to the normal working state. After the modification is completed, the baud rate needs to be re-powered to take effect.
Note: when changing the baud rate, it needs to be the same in airborne unit, ground unit, flight control, or other devices for normal communication.
3.3VM31 status LED description
Light | state | meaning |
TXD | flashing | The module has data sending |
| Lights | No data is sent by the module |
RXD | flashing | The module has data sending |
| Lights | No data is sent by the module |
TTL/RS232 | flashing | The serial port has data input |
| Lights | There is no data input in the serial port |
| Blue light | Indicates the TTL level version |
| green light | Indicates the RS232 level version |
S-BUS 1 | flashing | S-BUS1 has a signal transmission |
| Lights | S-BUS1 does not transmit signals |
S-BUS 2 | flashing | S-BUS2 has a signal transmission |
| Lights | S-BUS2 does not transmit signals |
LAN | flashing | Indicates that the LAN port is connected |
LINK | LINK,BAND,POWER The green light is fully on | High frequency module has strong signal |
BAND | green light | Indicates the 800MHz band |
| red light | Indicates the 1.4GHz band |
| Yellow light | Indicates the 2.4GHz frequency band |
POWER | The lights are always on | Indicates that the power supply to the module is normal |
| Lights | Indicates that the power supply to the module is abnormal |
Safe protection data LINK,BAND,POWER | The green light flashes | Out-of-control protection data is being exported |
3.4 S-BUS Operation
1. Connect the SBUS port of VM31 ground unit with the SBUS signal source of RC receiver. The SBUS indicator will flash quickly when there is data input.
2. Connect the SBUS port of VM31 airborne unit to the device you need to control.
3. VM31 can control aircraft, gimbal and other equipment as long as the link is connected.
3.5 LAN Operation
The LAN interface is used to obtain pull-stream videos
Take Windows as example
1. Default IP address
Airborne unit：192.168.168.12； Ground unit: 192.168.168.11
2. Connect LAN port of the airborne unit to IPC devices.
3. Connect your computer to the LAN port of the ground unit, and make sure that the IP address of your computer’s local connection is on the same network segment as the camera.
① Open Computer network sharing center, click Network and Internet setting
②Open the Change Adapter option
③Select the local connection to the ground unit and right-click on it to view the properties. Select Internet IPV4 protocol, set the fixed IP, and set the IP to the same network segment as the camera, e.g.: the camera IP is 192.168.167.10, set the local IP to 192.168.167.xxx (0~255)
except 10. When the modification is finished, click “OK”.
④Video data can be captured and played using pull streaming software such as VLC media player.
- Please ignore the IP address of VM31 when setting up the video stream retrieval. Simply change the local IP address of the computer to the same network segment as the LAN camera.
3.6 USB Operation
The USB port incorporates a virtual network card function that can be used for video and data output. Before using the USB port, the user must install the appropriate driver. The steps as follows:
1. Install VM31 CODEDRIVER driver
2. The installation process may be intercepted by the security guard, please close the security guard or trust this operation. After the successful installation, connect the USB port to the PC, open Computer→Management, you can see 5 ports will appear in the port management interface (not open for use yet). < Remote NDIS based Internet Sharing Device> will appear in the interface of the network adapter, indicating that the USB port connection is successful.
Note: Please do not use the USB port until the device is successfully connected. Otherwise, the signal strength indicator may appear abnormal.
3.Open the Network Sharing Center and set the local connection to get static IP.
3.7 Mesh Operation
The VM31 radio supports mesh topology with one master device supporting up to 16 slave devices.
The ground unit can be set as the master device and the airborne unit as the slave device. The ground unit can communicate with up to 16 airborne units. The ground unit can broadcast data to 16 airborne units via the TTL interface. The airborne units can communicate with each
other through the LAN port. Specific steps:
1. Set the ground unit as the master node.
2. Set the airborne unit as the primary node.
3. The IP addresses of the ground unit and other airborne units must be in the same network segment and cannot have the same IP address to avoid IP conflicts and inaccessibility.
For example, the IP address of the ground unit is 192.168.168.11, and the IP addresses of the other airborne units are 192.168.168.12, 192.168.168.13…
4. Input data from the TTL interface of the ground unit, each TTL interface of the airborne unit can receive the data of the ground end.
5. The airborne unit accesses the devices connected to other airborne unit via the network port IPs, (e.g. webcams, etc) eg,
a. The IP of the webcam connected to the network port on airborne unit is 192.168.167.20;
b. Connect the airborne unit to the PC side via the LAN port and set the local connection to obtain an IP statically, with the IP in the same network segment as the webcam, e.g. 192.168.167.30;
c. Use pull stream software to play the video.
3.8 Module Configuration
Take <airborne unit LAN port IP: 192.168.168.12; Ground unit LAN port IP: 192.168.168.11> for example:
①Power on the modules. Wait for the module to start about 1 minute, connect the PC to the LAN port of the ground unit through the network cable to access the airborne unit directly from the ground unit, or connect the airborne unit to the computer separately.
②Set the local IP to static IP in the computer network sharing center, IP should be the in the same network segment with airborne unit IP, for example.192.168.168.100.
③Open a browser and enter IP in the address bar: 192.168.168.12
④Pop up the login interface and click on the administrator login, user name: admin123, password: admin123.
If you are unable to log in or see the message ‘This browser does not support ActiveObject, please download another browser (such as Sogou or Microsoft Edge) or update your browser version and try again.
⑤After successful login, the module configuration interface will appear.
< Key Settings Management> allows the user to set the secret key, which must be the same between the airborne unit and the ground unit for communication.
It is not recommended to modify the <Master-Slave Settings> of the <Wireless Settings> to avoid the possibility of poor communication quality due to improper settings.
<Wireless Settings> allows you to adjust the frequency band, bandwidth, power, and frequency hopping. When modifying the frequency band and bandwidth, ensure that the air unit and ground unit have matching frequency bands and bandwidths, and that the antenna model is consistent with the frequency band. Power adjustments can be made in <Link Management>. For example, within the power range of <-40dB ~ 25dBm>, change “-10dBm” to “10dBm”.
<IP Address Change Management> can modify IP addresses. It is not recommended changing the IP address randomly. If the user wants to change it, please make sure that the ground unit and the airborne terminal are on the same network segment.
The <Debug Interface> should be modified at the developer’s guidance. If the user needs a fixed-frequency point output, use the AT command: AT^DRPS.
The first parameter is the frequency point range, please set it according to the frequency point range of different frequency bands.
The second parameter is the bandwidth, 1 is 3M; 2 is 5M; 3 is 10M; 5 is 20M;
The third parameter is the power, which ranges from <40db ~ 25dbm>.
As show below:
⑥<Equipment Information> shows the current module version number. Please make sure that the version number of the airborne unit and ground unit is the same.
4. Remote Control Fail Safe Protection Setting
If the RC fail-safe protection is needed to be set, pls follow the below steps:
4.1 Write fail safe protection data
After the successful connection of the airborne unit and ground unit, long press the SET button about 5S when there is SBUS data transmission.
When RX, TX, S1, S2, S3 all lights ON, it means entering Failsafe data setting mode, then release the SET button.
Press SET button briefly to switch to write failsafe data or turn off fail-safe, when RX and TX flash, it means the setting is successful.
Long press SET button until RX, TX, S1, S2, S3 all lights ON, it means Failsafe data has been saved and exit setting mode.
After finishing the setting, the current RC value can be stored in the airborne unit as failsafe value, and will not be lost after power failure. S1, S2 and S3 will flash when failsafe data is output. Please test whether the Failsafe data is written successfully by the flight control, GCS or servo.
SET operation （proceed in the below order） | LED status | Mode |
Long press＞5s | All lights ON | Enter fail safe setting |
Short press＜1s | RX, TX flashing | Write fail safe data |
Short press＜1s | All lights OFF | Turn off fail safe data |
Long press＞5s | All lights ON | Exit fail safe setting mode |
4.2 Trigger Fail Safe Value
If the airborne unit does not receive SBUS data from the ground unit for 3 seconds, the airborne unit will keep outputting the Fail safe value written before, and the S1, S2, and S3 signal lights will flash until it receives SBUS data from the ground.
4.3 Turn off Fail Safe Value
Long press the SET key (about 5S) after powering on the airborne unit. When all lights ON, it means the Failsafe data setting mode has been entered, then release the SET key. Press SET button briefly to switch to <write fail-safe data> or <turn off fail-safe>. When RX, TX, S1, S2 and S3 are off, it means turning off fail-safe function. Press and hold SET button until RX, TX, S1, S2 and S3 are ON, it means fail-safe data is off.
4.4 Reset fail-safe data
If the user needs to reset the SBUS fail-safe data,
it enters fail-safe setting mode when there is RC SBUS data transmission. First, short press the SET button to cancel the fail-safe data set before, then short press the SET button briefly. When the RX and TX lights flash, it means the successful setting.
- By default, there is no fail-safe data output from the radio, it will continue to output the last received SBUS data after the data link is disconnected.
- Only the S-BUS channel that has input at that time will be triggered and deactivated fail-safe function. For example, if S-BUS1 channel has data transmission and S-BUS2 channel has no data transmission, pressing the key will only trigger and deactivate S-BUS1 fail-safe data.
- To set up fail-safe for both S-BUS1 and S-BUS2 at the same time, both S-BUS1 and S-BUS2 are required to have remote SBUS data transmission.
5. Firmware
5.1 Firmware Version View
In order to serve our customers better, our R&D team never stops the work. We are upgrading the firmware and software, so please check the firmware version when you use it and refer to our website for the latest version of software and firmware.
The version of the parameters setting software can be seen directly on the PC when you configure the parameters, and the firmware version can be viewed through the following steps
1. Connect the radio to the PC via USB cable, and a port will appear on the PC side.
2. Install the serial port debugging assistant on your PC and open this port. Port configuration parameters: 115200, 8N1. String display mode
3. After powering on VM31, the serial assistant will show the following firmware version information <VM31RX-1.0—-VM31RX-0.0.2—-sysbaud: 115200>.
VM31RX indicates the airborne unit, the first version number indicates the hardware version number of the firmware, and the second version number indicates the software version number of the firmware. As the above version number represents the VM31 airborne unit, the hardware version number is 1.0, the software version number is 0.0.2.
5.2 Firmware Upgrading
Please use the firmware upgrade tool to upgrade the firmware separately for the ground unit and airborne unit.
1. Connect V21 by TTL port (White – TX, Black – G, Green – RX) with the matched configuration cable, press the set key to power on, then release the key when the RX and TX indicators continuously ON. Open the upgrade software within 1 minute. After opening, the corresponding message will pop up, which means it is in upgrade mode.
2. Open upgrading software
3. Click, Open the correct firmware that is downloaded and if it is correct, it will show that the firmware file recognition is complete.
4. Click, until the firmware write is complete. It means successful upgrading.
6. Common Questions
1. Show weak signal strength
Check whether the antennas are connected well, whether there are other high-powered devices nearby, and adjust the distance between the devices and the orientation of the antennas.
2. Unable to stream video in the video player
Please make sure that the IP address of the receiver is in the same network segment as the IP camera.
3. Receiver SBUS has signal output, but the serial port is not connected, or the transmitted signal is garbled.
Please check if the baud rate of the serial port of the remote control and the receiver is the same; and set the baud rate to the corresponding baud rate of the ground station software.
4. Interference when more than two sets of device are turned on at the same time
Please check that the ID (key) must be different from each set, and set it differently to avoid co-frequency interference.
5. Significant packet loss and high latency of video transmission
a. Check and confirm the antennas are connected well
b. Check and confirm module versions are consistent
c. Check whether the module wireless setup parameter is consistent.
d. Check that other devices, device cables, and computer interfaces are working properly.
e. Check the settings of image streaming software or change other player
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