# Request for Support – CANFace CF1 "Babel" SLCAN Dongle **URL:** \ **Category:** Development & Maintenance\ **Created:** [August 14, 2025, 9:39am UTC](https://forum.opencyphal.org/t/request-for-support-canface-cf1-babel-slcan-dongle/2409 "2025-08-14T09:39:25Z")\ **Posts on this page:** 6\ **Page:** 1
**Author:** ![EmmanuelDuconge](https://forum.opencyphal.org/letter_avatar_proxy/v4/letter/e/eb9ed0/32.png) [@EmmanuelDuconge](https://forum.opencyphal.org/u/EmmanuelDuconge)\ **Post date:** [August 14, 2025, 9:39am UTC](https://forum.opencyphal.org/t/request-for-support-canface-cf1-babel-slcan-dongle/2409/1 "2025-08-14T09:39:26Z")
Hello, I’m experiencing recurring issues with the CANFace CF1 “Babel.” Initially, I used one unit for several weeks with different ESCs (Currawong and Hargrave). Eventually, the device stopped working entirely — my computer no longer recognized it, and it also stopped appearing in the DroneCAN GUI Tool. The only sign of life was the red LED constantly on. I purchased a second CANFace CF1, but after a few weeks a similar issue appeared. This time, the dongle is recognized by my computer, but it cannot initiate a stable connection to the ESC. Occasionally, I receive telemetry from the ESC, but it disappears after a few seconds. I have verified that: - Wiring is correct and unchanged - CAN bitrate matches on both ends - Termination and power supply are consistent At this point, I’m unsure whether this is a hardware failure, configuration issue, or something else. Any guidance would be greatly appreciated. Thank you for your help. ---
**Author:** ![pavel.kirienko](https://forum.opencyphal.org/user_avatar/forum.opencyphal.org/pavel.kirienko/32/9_2.png) [@pavel.kirienko](https://forum.opencyphal.org/u/pavel.kirienko)\ **Post date:** [August 14, 2025, 1:48pm UTC](https://forum.opencyphal.org/t/request-for-support-canface-cf1-babel-slcan-dongle/2409/2 "2025-08-14T13:48:19Z")
Hi Emmanuel, Babels tend to be quite reliable; a single failure is unlikely to occur, while two of them failing in quick succession might suggest that there is a problem with your setup. Could you share a description of your electrical setup, with a particular focus on how the grounds of the various components are connected together? Also, what might help is to grab a multimeter and measure the ground current between the babel and the CAN bus it is connected to. Cheers! Pavel. ---
**Author:** ![EmmanuelDuconge](https://forum.opencyphal.org/letter_avatar_proxy/v4/letter/e/eb9ed0/32.png) [@EmmanuelDuconge](https://forum.opencyphal.org/u/EmmanuelDuconge)\ **Post date:** [August 14, 2025, 3:40pm UTC](https://forum.opencyphal.org/t/request-for-support-canface-cf1-babel-slcan-dongle/2409/3 "2025-08-14T15:40:05Z")
Hi Pavel, Thank you for your prompt reply. As mentioned earlier, I use the Babel to interface with different ESCs (mostly from Currawong and Hargrave), since both use the DroneCAN (or similar) protocol. My electrical setup is fairly straightforward — I connect CANH, CANL, and GND from the Babel directly to the corresponding pins on the ESC. In some cases, I also send a PWM signal to control the ESC, while keeping the Babel connected via CAN to my computer for telemetry. In those situations, the PWM and CAN connections do **not** share the same ground. Could this ground separation be a potential cause of the issue… ground loop? ---
**Author:** ![pavel.kirienko](https://forum.opencyphal.org/user_avatar/forum.opencyphal.org/pavel.kirienko/32/9_2.png) [@pavel.kirienko](https://forum.opencyphal.org/u/pavel.kirienko)\ **Post date:** [August 14, 2025, 4:00pm UTC](https://forum.opencyphal.org/t/request-for-support-canface-cf1-babel-slcan-dongle/2409/4 "2025-08-14T16:00:36Z")
Please describe how your ESCs are powered and where that ground is also connected besides your PC ---
**Author:** ![EmmanuelDuconge](https://forum.opencyphal.org/letter_avatar_proxy/v4/letter/e/eb9ed0/32.png) [@EmmanuelDuconge](https://forum.opencyphal.org/u/EmmanuelDuconge)\ **Post date:** [August 14, 2025, 4:19pm UTC](https://forum.opencyphal.org/t/request-for-support-canface-cf1-babel-slcan-dongle/2409/5 "2025-08-14T16:19:00Z")
The ESCs are powered via a bench power supply. The Babel is connected to my PC via USB. In some cases, when I also use PWM control, my PC is connected to a separate PWM generator to control the ESC duty cycle. The PWM generator is powered from the mains (grid connection). However, when the issue with the Babel occurred, I was only attempting to connect via CAN — no PWM generator was connected at that time. ---
**Author:** ![pavel.kirienko](https://forum.opencyphal.org/user_avatar/forum.opencyphal.org/pavel.kirienko/32/9_2.png) [@pavel.kirienko](https://forum.opencyphal.org/u/pavel.kirienko)\ **Post date:** [August 14, 2025, 4:36pm UTC](https://forum.opencyphal.org/t/request-for-support-canface-cf1-babel-slcan-dongle/2409/6 "2025-08-14T16:36:38Z")
The ground potential of your PC may differ significantly from that of the bench power supply, depending on the design of their respective PSUs and their grounding schemes. Thus, as soon as you connect the grounds of the PC and the PSU together, a large current between them may result. You may use a multimeter to check. If this is indeed a problem, an easy solution is to use an off-the-shelf USB isolator.