What to Do if Merlin Can’t Connect to Your Weather Station
Initial COM Port Detection
When you click on the Merlin icon, the program performs an automatic COM port detection routine. If the weather station is turned ON and correctly connected to your PC you will see the Merlin Screen. Merlin will search for the weather station on COM ports 1-20.
Weather Station Not Found
The Weather Station Not Found dialog box pops up if Merlin can’t connect to the weather station for any reason. Merlin can’t connect to the weather station if there is a hardware failure such as if the weather station is not turned on, if a cable is loose, or if you haven’t installed the correct cable drivers.
If Merlin can’t connect to the weather station, first double check physical connections. Physically examine the listed items. Then check the items in the dialog box and click Connect to connect with the weather station.
Check Physical Connections to your PC
• AltaCom2 The AC2 weather station uses 2 cables in series, a 25m to 9f serial cable (supplied) and a usb to serial cable (optional). Plug the 25 pin male end of the serial cable into the back of the console, and attach the 9 pin end of that cable to a USB to Serial cable. Connect the usb end of the adapter to your PC. Refer to the AC2 manual for diagrams.
• AltaCom4x Connect the USB cable female end to the black Interface Box, and connect the male USB connect to to your PC. You may have to update the driver from with your PC’s Device Manager. Refer to the 4x Hardware Manual for a diagram.
• AltaCom4xR Plug the USB cable female end to the 4xR Console and connect the male USB end to your PC. You may have to update the driver from with your PC’s Device Manager. Refer to the 4xR Hardware Manual for a diagram.
Close Competing Software
Only one program can connect to your weather station at a time, so you cannot have Crew Chief or DragStat or another logbook program running at the same time you want Merlin to connect to your PC. The first program to connect will commandeer the COM port, preventing another program from communicating with your weather station.
Check Software and Driver Versions
Make sure your Merlin is the latest version. In Merlin click Help > About Merlin to check the version you have. On our website, visit https://altalabinstrument.com/support/download-altalab-software/ to see if you have the latest version available.
Make sure your PC has a supported operating system (OS). Merlin 8 supports Windows XP, Windows 7, 8, 10, and 11. We do not support Windows Vista.
Make sure your usb cable (for AC2 the usb to serial cable) has the correct driver installed. In your PC, go to the Device Manager. If correctly installed the cable will show up under Ports (COM & LPT). If it does not, ie if it shows up as Other Devices, right click and choose update driver. In Windows 10, 11 you can find the device manager by typing Device Manager in the Windows Search Bar. Here’s a resource to find the device manager in older Windows operating systems. https://www.lifewire.com/how-to-open-device-manager-2626075
In the Update Driver window your best choice is to Search Automatically for Drivers. If you do not have an internet connection, or are unsuccessful, use the second option Browse My Computer for Drivers. There is a Drivers folder on your Merlin installation thumb drive. You may also be able to download a driver from https://www.ftdichip.com/Drivers/CDM/CDM21228_Setup.zip
Once in the Device Manager here are some weird but sometimes effective steps to try.
- Right-click the device and choose “update driver” (or Properties > update driver). Choose “Search Automatically” for a driver. You must be connected to the internet. After updating the driver, unplug the cable at the PC then reattach, then reboot your PC.
- If you are not sure where the cable is listed in Device Manager, unplug and reattach the cable from the PC while the Device Manager is open. The display will update live and you may be able to locate the item as it disappears and reappears.
- If Windows says you have the correct driver but you are still not able to connect, download a driver from https://www.ftdichip.com/Drivers/CDM/CDM21228_Setup.zip and manually choose the location of this file to update the driver.
Check Device Manager Settings
Merlin requires the cable to be set to port 1-20. Right click the item in the Device Manager, and choose Properties > Port Settings > Advanced. That screen will allow you to manually choose an appropriate COM port.