Hello everyone,
I am having trouble connecting my Radiolink Pixhawk 2.4.8 flight controller (running ArduPlane firmware) to Mission Planner using a Holybro 3DR 500 mW 915 Mhz Radio Telemetry Set v3.
My Hardware:
Flight Controller: Radiolink Pixhawk 2.4.8 (ArduPlane V4.5.7)
Telemetry Set: Holybro 3DR 500 mW 915 Mhz Radio Telemetry Set v3 (Ground and Air Modules)
Ground Station Software: Mission Planner (Version: 1.3.82)
Operating System: Windows (Version: Windows 10)
Ground Module USB Chip: FTDI (Seems to be FT232TL based on Device Manager)
Basic Problem: I cannot establish a wireless telemetry connection to the Pixhawk from Mission Planner.
Telemetry Radio LED Status (When trying to connect wirelessly):
- Ground Module (Connected to PC via USB): Green LED is blinking. (It seems to be blinking slowly). Red LED is off or not noticeably active. (If your red LED sometimes blinks rapidly, you can add: “Sometimes the red LED blinks rapidly next to the green one.”)
- Air Module (Connected to Pixhawk): Green LED is blinking. Red LED is blinking rapidly.
This LED status indicates that the two telemetry radio modules are not establishing a wireless link between each other.
Attempted Step to Fix (But Failed): I understand that to fix the radio link (make the green LEDs solid), I need to match the settings (especially Net ID) on both radios using the SiK Radio tab in Mission Planner (Initial Setup → Optional Hardware → SiK Radio).
Errors Encountered When Trying to Access SiK Radio Settings (Main Obstacle): When I connect the ground telemetry module to my PC via USB and try to access the SiK Radio tab (e.g., by clicking “Load Settings”), I consistently get the following errors:
-
Error 1: “Error during read System.InvalidOperationException: Bağlantı noktası kapalı.” (
) -
Error 2 (Sometimes get this one instead): “Failed to enter command mode. Try power-cycling modem.” (
)
These errors prevent me from accessing the radio settings in the SiK Radio tab, so I cannot check or match the Net ID or other parameters.
Troubleshooting Steps Attempted So Far (Without Success):
- Tried different USB cables for the ground module.
- Tried different USB ports on my computer for the ground module.
- Verified the correct COM port and Baud Rate (57600) are selected in Mission Planner connection settings.
- Verified the port settings in Windows Device Manager (57600, 8, None, 1, None) - they seem correct. (You can add: “Included a screenshot of Device Manager port settings.”)
- Downloaded and installed the latest FTDI VCP drivers. (You can add: “I used the FTDI UNIN tool for a complete clean removal before reinstalling.”)
- Restarted the computer multiple times after driver installation.
- Followed advice to configure Pixhawk’s TELEM2 port for telemetry and physically moved the air module cable from TELEM1 to TELEM2. (The radios still do not link after this).
- Physically cleaned the USB ports and telemetry connectors (removed dust).
- Tried the suggested fix for Mission Planner freeze (“Connect reset” toggle in Planner settings).
- Tried power-cycling the telemetry modules by unplugging/replugging USB.
- Checked the Holybro V3 modules for a physical reset/boot button (I couldn’t find one on my modules, though some documentation mentions one).
Specific Questions / Request for Help:
- The main problem is the radios not linking (blinking green). I understand this is likely due to mismatched settings (Net ID).
- However, I am blocked from fixing the radio settings by the “Bağlantı noktası kapalı” and “Failed to enter command mode” errors when trying to access the SiK Radio tab.
- What are the most likely causes for these specific errors, and are there any other troubleshooting steps I can take on my current computer setup to resolve the COM port access issue?
- If these errors cannot be fixed on my current PC, I understand testing the ground module on a different computer is recommended to determine if the module is faulty.
Any help or suggestions to overcome the “Bağlantı noktası kapalı” / “Failed to enter command mode” errors would be greatly appreciated, as this is preventing me from proceeding with the telemetry setup.
Thank you!