Before you begin
Install SPX with the KNX package and SPX UI. Have a reachable KNX/IP tunnelling gateway and a client that sends raw group values. Use the lighting-zone YAML linked in the communication reference.
Run the test
- Import the YAML in Models → Load model from file. Create a fresh instance with your gateway host/port and ga_main=7, then start it. Connect your client to the same gateway.
- Send GroupValueWrite to 7/1/10 with one raw byte 0x23 (decimal 35). This binding uses uint8 percentages 0–100, rather than DPT 5.001 scaling or ASCII digits.
- Wait for the lighting ramp to settle. Send GroupValueRead to 7/1/10 and inspect the GroupValueResponse.
Check the result
The actual-level response is 0x23 / 35%. An earlier response may show an intermediate ramp value. Restore the fresh model’s target 70% with raw byte 0x46, verify it after settling, then stop the instance.
Protocol communication
Use these settings and messages with the library’s lighting zone model.
- Client / transport
- KNX/IP tunnelling → GATEWAY_HOST:3671 over UDP; same gateway as SPX
- Address override
- ga_main=7 for this exercise; library default: 1
- Brightness codec
- uint8; one raw byte in 0–100, not DPT 5.001 scaling
Replace host placeholders with reachable addresses and use your published ports.
Swipe the table to see requests and replies.
| Address / message | Operation / payload | Expected reply |
|---|---|---|
7/1/10 | Circuit A: GroupValueWrite raw 0, 100 or 35; GroupValueRead | GroupValueResponse: actual brightness, eventually 0, 100 or 35 |
7/1/11 | Circuit B: same read/write uint8 format | Actual Circuit B brightness in 0–100% |
7/1/14 | Occupancy: GroupValueWrite; boolean true/false; inbound only | No direct readback binding; check occupancy_detected in SPX |
7/1/15 | Daylight: read / outbound updates; DPT 9.004 | Measured illuminance in lx; varies with the scenario |
Values describe this model’s nominal setup unless noted. Live measurements change as the simulation runs.
Example request and reply
Write 0, then 100, then 35 to 7/1/10, waiting for each ramp to settle. Issue GroupValueRead after each step and verify the actual-level response.
GroupValueWrite 7/1/10 payload: 0x64 (decimal 100)
Wait for the ramp; GroupValueRead 7/1/10
→ GroupValueResponse payload: 0x64 (100%)
GroupValueWrite 7/1/10 payload: 0x23 (decimal 35)
Wait; GroupValueRead 7/1/10
→ GroupValueResponse payload: 0x23 (35%)No reply or an unexpected value?
- Target writes and actual feedback share 7/1/10 in this model. An immediate read may return an intermediate ramp value.
- Decimal 35 is raw byte 0x23; decimal 100 is 0x64. Do not send ASCII text or scale 100% to 255.
- Allow enough gateway tunnels for SPX and your client. If your instance uses ga_main=1, replace 7/... with 1/... on every group address.
Next steps
See the lighting walkthrough with 0 → 100 → 35% steps. For adapter settings, use the KNX guide.