KNXEye 26 — see what's
happening on the KNX bus.
A bus monitor and group monitor that watch installations for days, record several lines at once and find faults on their own. No ETS licence required.
KNXEye 26 connects via KNX USB or KNXnet/IP including IP Secure, shows every telegram in plain text with the names from your ETS project and analyses the traffic straight away: bus load, errors, repetitions, routing counter and programming operations. Sporadic faults? Just record them — KNXEye e-mails you the files.
KNXEye 26Group monitor with two channels: the same telegram before and after the line coupler, with names and values from the ETS project. (Illustration recreated.)
Diagnostics as you know them from ETS — and more
For service technicians, electrical installers, system integrators and facility management.
Diagnostics without an ETS licence
Bus and group monitor in the familiar ETS layout, as a standalone program. Ideal for service technicians, caretakers and colleagues without an ETS licence.
Several lines at once
Up to eight interfaces in parallel — main line and sub-lines in one list, each line in its own colour. KNXEye recognises the same telegram before and after the coupler and shows the time offset.
Track down sporadic faults
Long-term recording runs for days or weeks, switches files at the set interval and sends every period by e-mail, HTTP or FTP. You only drive out once you know what happened.
Analysis, not a flood of telegrams
Statistics and analysis show bus load, errors, BUSY/NAK, repetitions, the most active senders and group addresses, unknown addresses and routing-counter implausibilities — live or from a recording.
Who did the programming?
Programming analysis detects programming operations: which device, from which address, and what (individual address, application, partial download, Data Secure). KNXEye determines the programmer's line via the routing counter.
Your ETS project in plain text
Import a .knxproj, even password-protected. Every telegram carries device names, group address names and the decoded value. Topology and building tree as in ETS; query the group values of a device, line or room with one click.
Every interface, IP Secure included
KNX USB, KNXnet/IP tunnelling over UDP and TCP, KNX IP Secure with keyring, and routing. Automatic interface discovery, reconnection after a dropout, autostart.
Compatible with ETS
Save and open recordings in ETS format, CSV export, columns and terms as in ETS including Iack. If you know ETS, you'll feel at home right away.
Also: time filter with “Go to” · send, read and respond on group addresses · 19 languages · automatic updates
From a single telegram to a weekly analysis
Bus monitor
Shows every frame on the line, including faulty frames and acknowledgements. Columns as in ETS: time, source, destination, routing counter, type, value, flags and Iack (ACK, NAK, BUSY). Negative acknowledgements and errors are highlighted in colour. Available via KNX USB and KNXnet/IP tunnelling.
Group monitor
All group telegrams with names and decoded values from the ETS project. Write, read and respond to values, also via a freely selectable channel. The “Topology” and “Rooms” tabs show all group values of a device, line or room; “Read all” queries exactly those.
Time filter and search
From/to, last 1, 5, 15 or 60 minutes, a window around a marked telegram and “Go to”. That's how you find the moment the light went off, even in large recordings.
ETS project
Import of .knxproj files, password-protected ones too, from ETS4, ETS5 and ETS6. Topology, building and “All devices” views with selection by manufacturer, device type and location. Imported projects stay in the history and open again without re-entering the password.
Statistics and analysis
Key figures, telegram rate, errors, BUSY, NAK and repetitions, top lists of senders and group addresses, unknown addresses (not in the project), plausibility check of the routing counter per line, and coupler comparison. Either live or for an opened recording, per channel and time range.
Programming analysis
Detects which devices are being programmed: individual address (with previous address or serial number), application and parameters, partial download, Data Secure, restart, read-only access. Shows the source and its line — the line determined via the routing counter, not just from the address.
Long-term recording
Runs in the background, independently of the user interface. A new file at the set interval; every file is valid at all times and readable in ETS. Delivery by e-mail, HTTP or FTP with a queue when the connection is down. Per period also a programming log and statistics files (CSV). Old files are cleaned up automatically.
Multi-channel
Up to eight recording channels (A–H), each with a label and the individual address of its interface. All channels in one shared list, switchable. The “Coupler” column shows the same telegram on two lines with its time offset.
Interfaces
| Connection | Bus monitor | Group monitor | Send |
|---|---|---|---|
| KNX USB | ✓ | ✓ | ✓ |
| KNXnet/IP Tunneling (UDP/TCP) | ✓ | ✓ | ✓ |
| KNX IP Secure (Tunneling) | ✓ | ✓ | ✓ |
| KNXnet/IP Routing | –technical limitation | ✓ | ✓ |
Six typical jobs
Commissioning
Check that push buttons, actuators and visualisation send to the right group addresses. Write and read values directly without opening ETS.
Sporadic faults
“Every now and then the light switches on by itself.” Start long-term recording, drive home, analyse the files that arrive by e-mail. The time filter takes you straight to the reported moment.
Overloaded or disturbed lines
Bus load, repetitions, BUSY/NAK and chatty senders at a glance. With two channels before and after the line coupler you can see whether the coupler filters as it should.
Unknown devices and outside access
Unknown addresses and programming operations reveal who is active on the bus without belonging to the project.
Service and maintenance
Service technicians and facility management without their own ETS licence get a fully fledged diagnostic tool.
Documentation and acceptance
Hand recordings and statistics to the client, planner or manufacturer as an ETS file or CSV.
Try first, license later
Download KNXEye 26 and request a free trial licence inside the program. For professional use, KNXEye 26 is available as an annual licence.
- All features, all interfaces
- Check that KNXEye works with your interface
- Usable even without a licence: open recordings, view ETS projects
- Annual licence for one computer, 12-month term
- All features, all interfaces, all 19 languages
- Updates included during the term
- Licence code by e-mail, activation right in the program
Purchase & payment run securely via the busbaer.de shop. The licence is tied to one computer; if you change computers, please get in touch. After expiry you can still open recordings and view ETS projects, but no longer connect to the KNX bus.
Windows, Linux and Raspberry Pi
| Operating system | Windows 10 or 11, 64-bit Linux x64 Raspberry Pi 4 or 5 with Raspberry Pi OS 64-bit (Bookworm or later) |
| Installation | Windows: none — a single program file, .NET included Linux: unpack the archive, run bash install.sh — sets up the menu entry and the KNX USB rule |
| Interface | KNX USB or KNXnet/IP interface or router (tunnelling UDP/TCP, IP Secure, routing) |
| ETS project | optional, .knxproj from ETS4, ETS5 or ETS6 |
| Internet | for licence activation, updates and delivery of long-term recordings |
After that, the program updates itself on request. macOS is on its way.
Frequently asked questions
Do I need an ETS licence?
No. KNXEye 26 is a standalone program. An ETS project is optional and makes the display easier to read — ETS itself does not need to be installed.
How much does KNXEye 26 cost?
€59.00 plus VAT (€70.21 incl. 19% German VAT) for an annual licence with a 12-month term on one computer. All features and updates during the term are included.
How can I try KNXEye?
Download the program, start it and choose “Request trial licence” in the activation window. Without a licence you can already open recordings and view ETS projects; to connect to the bus you need the trial or annual licence.
Which interfaces are supported?
KNX USB interfaces as well as KNXnet/IP interfaces and routers: tunnelling over UDP and TCP, KNX IP Secure and routing. KNXEye automatically lists the interfaces it finds on the network.
Why is the bus monitor not available via routing?
KNXnet/IP routing only carries finished telegrams, not raw bus frames with acknowledgements. That is defined in the KNX standard and applies to every program. For the bus monitor use tunnelling or USB; the group monitor also works via routing.
What is the difference between the bus monitor and the group monitor?
The bus monitor shows everything that happens on the line — including faulty frames and acknowledgements (ACK, NAK, BUSY). It only listens. The group monitor shows group telegrams with names and values and can itself send, read and respond.
Can I watch several lines at the same time?
Yes. Up to eight interfaces run in parallel, all telegrams appear in one shared list, each line in its own colour. KNXEye automatically recognises the same telegram before and after a coupler.
How do I find a fault that only occurs occasionally?
With long-term recording. It runs in the background for days or weeks, creates a new file at the set interval and sends it by e-mail, HTTP or FTP. In the recording, the time filter takes you to the reported moment.
Can I use my ETS projects?
Yes. KNXEye reads .knxproj files from ETS4, ETS5 and ETS6, including password-protected ones. Devices, group addresses, datapoint types and the building structure are imported.
Can I exchange recordings with ETS?
Yes. KNXEye saves and opens recordings in ETS format. There is also a CSV export for Excel.
What does the programming analysis show?
It detects programming operations on the bus: which device was programmed from which address, and what — individual address, application, parameters, Data Secure. So you can see when and from where the installation was accessed.
Can KNXEye change the installation or program devices?
No. KNXEye does not program devices. It only sends when you deliberately write, read or respond to a value in the group monitor. The bus monitor never sends anything.
Does KNX IP Secure work?
Yes, via the ETS keyring (.knxkeys). The keyring password is stored encrypted so that autostart and automatic reconnection also work with IP Secure.
Does KNXEye run on Mac or Linux?
Linux yes, Mac not yet. KNXEye runs on Windows 10 and 11, on Linux (x64) and on the Raspberry Pi 4 or 5 with Raspberry Pi OS 64-bit (Bookworm or later). A macOS version is in preparation.
Do I have to install anything?
Not on Windows: KNXEye is a single program file that brings everything it needs. On Linux you unpack the archive and run install.sh — it creates the menu entry and the rule for KNX USB interfaces. On both systems the program installs new versions itself on request.
Can I transfer the licence to another computer?
The licence is tied to one computer. If you change computers, please get in touch with us.
Which languages are available?
19 languages, including German, English, French, Spanish, Italian, Dutch, Polish, Turkish, Chinese, Japanese and Arabic.
Another question? See the manual (German) — or write to us at info@busbaer.de.
See what's going on on the bus.
Download KNXEye26.exe, start it, request a trial licence — and see your first telegram in plain text within minutes.
Get in touch
Imprint
Alexander Maier GmbH
Beckstraße 3
D-69412 Eberbach
Managing director: Alexander Maier
Registered office: Eberbach
Register court: Mannheim
Commercial register: HRB 335404
VAT ID: DE177682654
Phone: +49 (0) 6271 – 91 94 70
E-Mail: info@busbaer.de