USB accessories
What each accessory connects, how to bring it up, and the compatibility reference behind it.
The Energy Pro has one USB 2.0 port. It accepts one accessory at a time: the root hub is a single port and USB hubs are not supported, so an accessory cannot be stacked behind another. The port supplies 500 mA, which is enough for every accessory OptiBee supplies and not enough for a bus-powered disk.
Pick the accessory from the accessories page. This page is what you need once it is in your hand.
Before you plug anything in
- Fit the accessory before you energise the cabinet where the cabinet layout allows it. The port sits on the front face and stays reachable afterwards.
- Only one accessory is active. Swapping one for another is a deliberate change of the installation, not a runtime option.
- Give the device up to a minute after a swap. Bring-up is automatic, but the interface is renamed and reconfigured before it reports ready.
Wi-Fi adapter
The wireless interface comes up as usbwifi0 and is configured like any other
network interface on the device. Prefer 5 GHz where the cabinet allows it: a
steel enclosure costs more signal than the difference between the two bands.
Measured on the device, same room, same access point:
| Adapter | PHY rate | Band | Upload | Download |
|---|---|---|---|---|
| RTL8811CU | 433.3 Mbit/s | 5 GHz · 80 MHz VHT | 6.26 MB/s | 10.95 MB/s |
| RTL8188EU | 72.2 Mbit/s | 2.4 GHz | 1.20 MB/s | 2.08 MB/s |
Both figures are far above what energy optimisation needs. They matter when you are deciding whether to pull a cable, not whether the system will work.
Wi-Fi 6 dongles are not supported. RTL8832AU, RTL8851BU, RTL8852AU, mt7921u and mt7925u have no driver on the device and will not come up.
Ethernet adapter
The second wired interface comes up as usbnet0, separate from the built-in
LAN port. Use it to keep an inverter or device network apart from the building
network rather than to gain bandwidth.
RS485 adapter
The adapter appears as /dev/usbserial0 and is added as a third field bus
alongside the two integrated RS485 segments. Termination and biasing follow the
same rules as the integrated buses; see Field bus.
CAN adapter
The CAN interface comes up as usbcan0. Bit rate is set per installation and
has to match the battery or device it talks to.
KNX adapter
The KNX interface is addressed as usb://<vid>:<pid> and is spoken to by the
KNX app rather than by a kernel driver, using cEMI over usbfs. KNX interfaces
following KNX Standard 9/3 with HID reports work; the Weinzierl KNX-USB family
and its rebrands are what we test with.
Re-plugging requires a restart. The KNX app is given the device node that existed at start-up, so unplugging and re-plugging the interface leaves it unreachable until the device is restarted. Plan the KNX interface as a permanent part of the installation.
KNX has no device templates: what a group address means is decided by the ETS project, so you supply the point list when you register the installation.
Service USB
A storage device is mounted under /run/media and is used for authorised
offline updates and service operations. Any USB mass storage device is
recognised; the service procedure itself is documented separately.
Logs are not written to the stick.
Compatibility reference
You do not need this section to install an accessory OptiBee supplied. It is here so that a device already on site can be identified.
| Accessory | Drivers on the device | Controllers |
|---|---|---|
| Wi-Fi | rtw88 · mt76 · rtl8xxxu | RTL8811CU/8821CU · MT7610U · RTL8188EU/8188FU/8192/8723 |
| Ethernet | ax88179_178a · r8152 · smsc95xx · lan78xx · aqc111 · cdc_ether · cdc_ncm · rndis_host · dm9601 · mcs7830 | AX88179/AX88772 · RTL8152/8153 · LAN95xx/75xx/78xx · AQC111 · CDC ECM/EEM/NCM · RNDIS |
| RS485 | cp210x · ch341 · pl2303 · ftdi_sio · cdc-acm | the usual USB serial bridges |
| CAN | gs_usb · peak_usb · 8dev_usb · esd_usb · mcba_usb · ucan | CANable / candleLight and the listed families |
| KNX | none — cEMI over usbfs, spoken by the KNX app | KNX Std 9/3 HID interfaces |
| Storage | usb-storage | USB mass storage |
Not supported at all: USB hubs, USB-WWAN and LTE modems, and the Wi-Fi 6 parts listed above.