Security Alarm Floodlight Automation with KNX: Alarm GA to DALI Scene and CCTV Coordination
Integrating perimeter floodlights with the KNX alarm system creates an automated response to intrusion — instant full illumination of the triggered zone, CCTV camera PTZ repositioning for recording coverage, and instant notification to security personnel. All actions are coordinated by a single alarm group address telegram.
Alarm GA architecture: DPT 1.005 and zone mapping
Each security zone has a dedicated KNX alarm group address using DPT 1.005 (alarm bit — same as DPT 1.001 but semantically indicates alarm state). The alarm GA is written by the PIR sensor or CCTV relay connected via a KNX binary input, and all responses — DALI scene, email alert, CCTV PTZ — subscribe to the same GA.
KNX alarm GA scheme — perimeter security zones
Zone 1 — Garden perimeter (north):
Alarm GA: 11/0/0 DPT 1.005 Alarm bit
Source: Binary input I1 ← PIR Optex BX-80N dry contact
Actions on GA 11/0/0 = 1 (alarm):
→ DALI Group 1 → Scene 8 (100% brightness)
→ BewO email: "Zone 1 Garden alarm activated"
→ CCTV PTZ Camera 1 → Preset 3 (north garden view)
→ 15-minute hold timer start (GA 11/0/0 remains 1)
Zone 2 — Entrance gate:
Alarm GA: 11/0/1 DPT 1.005
Source: Binary input I2 ← gate PIR or CCTV motion relay
Actions on GA 11/0/1 = 1:
→ DALI Group 3 → Scene 8 (100% brightness)
→ BewO email: "Zone 2 Entrance alarm activated"
→ CCTV PTZ Camera 2 → Preset 1 (entrance gate view)
Zone 3 — Parking area (south):
Alarm GA: 11/0/2 DPT 1.005
Source: Binary input I3 ← parking PIR coverage
Actions on GA 11/0/2 = 1:
→ DALI Group 2 → Scene 8 (100% brightness)
→ BewO email: "Zone 3 Parking alarm activated"
→ CCTV PTZ Camera 3 → Preset 2 (parking area view)DALI scene command on alarm: full brightness in one telegram
The KNX-DALI gateway maps the alarm GA to an immediate DALI scene command for the relevant luminaire group. DALI scene 8 is reserved for alarm/maintenance full brightness across all outdoor groups — a convention that simplifies commissioning and avoids ambiguity during response.
| DALI scene | Level | Purpose | Trigger |
|---|---|---|---|
| Scene 1 | 20% (DALI 51) | Night economy base | Twilight ON, no motion |
| Scene 2 | 40% (DALI 102) | Entrance base | Twilight ON, entrance zone |
| Scene 4 | 60% (DALI 153) | Business hours normal | KNX time 07:00–22:00 |
| Scene 8 | 100% (DALI 254) | Alarm / maintenance / full | Security alarm GA or manual |
| Off (Scene 0) | 0% (DALI 0) | Daytime off / night-off | Twilight OFF or night-off timer |
KNX-DALI gateway alarm scene configuration
KNX-DALI gateway (e.g. ABB DALI Gateway DG/S 8.16.1):
Object 1: DALI Group 1 — Scene number input
GA: 11/1/0 (linked to alarm logic output)
DPT: DPT 5.001 (1-byte scene number, value 8 = Scene 8)
Alarm logic in MDT Logic Module:
Input: GA 11/0/0 (Alarm bit Zone 1 = 1)
Output: GA 11/1/0 = value 8 (Scene 8 command to DALI Group 1)
After 15-minute hold timer:
Output: GA 11/1/0 = value 1 (Scene 1, return to base 20%)
Note: DALI scene commands are NOT overridden by PIR motion boost
during alarm state — alarm Scene 8 takes priority.
Clear alarm (GA 11/0/0 = 0) before PIR motion boost resumes.CCTV PTZ preset command coordination
Repositioning a PTZ (Pan-Tilt-Zoom) CCTV camera to a preset view when the alarm activates ensures the recording covers the triggered zone. The KNX system sends an HTTP command via Home Assistant or the ARISTO BewO HTTP action to the camera management system.
CCTV PTZ preset command via Home Assistant KNX bridge
Integration path:
KNX Alarm GA → Home Assistant KNX integration → HA automation
HA automation → ONVIF service call → PTZ camera preset
Home Assistant automation (simplified):
trigger:
- platform: state
entity_id: binary_sensor.knx_alarm_zone1
to: "on"
action:
- service: onvif.ptz
target:
entity_id: camera.perimeter_ptz_1
data:
preset: "3" # Preset 3 = North garden view
Alternative: ARISTO BewO HTTP action on alarm GA
BewO alarm object GA 11/0/0:
On alarm trigger: HTTP GET
URL: http://<camera-IP>/cgi-bin/ptz.cgi?action=goto&preset=3
Method: GET (no authentication for internal network)
PTZ preset programming (HIKVISION example):
Camera webUI → Configuration → PTZ → Patrol Settings
Preset 1: Entrance gate coverage (pan 0°, tilt -15°, zoom 2×)
Preset 2: Parking area wide (pan 90°, tilt -20°, zoom 1×)
Preset 3: North garden (pan 180°, tilt -10°, zoom 1.5×)ARISTO BewO alarm email with zone name
ARISTO BewO monitors KNX group addresses and sends email or SMS notifications when alarm conditions are detected. Each zone gets a separate alarm object in BewO with a descriptive name that appears in the notification subject line.
ARISTO BewO alarm configuration
BewO Alarm Module → Add alarm object:
Object name: "Zone 1 – Garden perimeter"
Group address: 11/0/0
DPT: DPT 1.005
Alarm value: 1 (alarm active when GA = 1)
Priority: High (immediate notification)
Notification settings:
Email to: security@building.com, fm@building.com
SMS to: +44 7xxx xxx xxx (if SMS gateway configured)
Subject: "ALARM: Zone 1 – Garden perimeter activated"
Body: "KNX security alarm triggered at [timestamp].
Zone: Garden perimeter (north façade).
DALI floodlights activated at 100%.
Please verify via CCTV camera 1, preset 3."
Acknowledgement: BewO requires email reply or BewO app
acknowledgement to clear alarm log entry.
Alarm remains active in log until acknowledged.
Alarm history: BewO stores 12-month alarm log with timestamp,
zone name, and acknowledgement record for security audit trail.KNX arming and disarming schedule
The security system must be armed only during unoccupied periods to prevent nuisance alarms from legitimate building users during business hours. A KNX time controller provides the armed/disarmed scheduling, with a KNX keypad at the entrance for manual override.
KNX arming schedule and override
KNX time controller (MDT SCN-TC8.01):
Armed GA: 11/5/0 DPT 1.001 (1=armed, 0=disarmed)
Automatic schedule:
Monday–Friday:
07:45 → GA 11/5/0 = 0 (disarm, staff arriving)
18:30 → GA 11/5/0 = 1 (arm, office closing)
Saturday–Sunday:
00:00 → GA 11/5/0 = 1 (armed all day)
Alarm logic gate (MDT Logic Module):
Input 1: GA 11/5/0 (Armed = 1)
Input 2: GA 11/0/x (Zone alarm bit)
Output: AND gate → alarm action (DALI + email + PTZ)
When disarmed (GA 11/5/0 = 0):
→ AND output = 0 regardless of PIR state
→ No alarm actions triggered
→ PIR binary inputs still visible in ETS6 Group Monitor
KNX keypad override (Gira 2-fold push-button):
Button 1 long press: GA 11/5/0 = 0 (manual disarm, 1-hour override)
Button 2 long press: GA 11/5/0 = 1 (manual arm ahead of schedule)Fail-safe design: floodlights ON when KNX power is lost
A critical security requirement is that perimeter floodlights illuminate when the KNX system loses power — not turn off. Standard DALI drivers default to the DALI system failure level when bus communication is lost, which can be programmed to 100%. Additional protection uses fail-safe thermal actuators.
Fail-safe DALI and KNX power-loss design
DALI driver system failure level (SFL) programming: Configure via DALI commissioning tool (DaliConnect or Osram OPTOTRONIC): Goto 254 (100%) on DALI bus fail → security zone drivers Goto 51 (20%) on DALI bus fail → non-security zones (energy saving) DALI bus fail = no valid DALI commands for >500ms → driver reverts to programmed SFL automatically KNX power-loss protection for security zone supply: Security zone floodlights: fed from dedicated MCB UPS backup: 48VDC UPS → 230VAC inverter → security zone MCB Autonomy: 2 hours at 100% load (size UPS to total floodlight W) Thermal actuator fail-safe (for non-DALI zones): Use NC (normally closed) thermal actuator for security circuits KNX actuator deenergised = contacts closed = lights ON → On KNX power loss: lights turn ON automatically → Normal operation: KNX commands actuator open (lights OFF) → Inverted logic: KNX sends 0 to switch lights ON (NC actuator) Note: This design is counterintuitive for programmers — document clearly in ETS6 project: "Security Zone Output: KNX 0 = Light ON, KNX 1 = Light OFF (NC actuator logic)"
Insurance requirement: some building insurers require fail-safe external lighting as a condition of commercial contents cover. Verify with the building insurer before design — they may specify minimum lux levels at perimeter that must be maintained during power events. Document the fail-safe design and UPS autonomy in the O&M manual.
Commissioning test: alarm, DALI scene and email verification
Security lighting commissioning requires a full functional test of each zone with the security team present, verifying that all simultaneous actions — floodlights, CCTV, email — activate correctly and within acceptable latency.
Security lighting commissioning test sequence
Pre-test: Arm system (write 1 to GA 11/5/0 via ETS6 Group Monitor) Zone 1 test (Garden perimeter): 1. Trigger PIR Optex BX-80N (walk through zone) 2. Confirm GA 11/0/0 = 1 received in Group Monitor 3. Confirm DALI Group 1 luminaires at 100% (measure with luxmeter) 4. Confirm CCTV PTZ Camera 1 moves to Preset 3 (verify on VMS screen) 5. Confirm BewO email received: check subject and timestamp (< 30s) 6. Wait 15 minutes: confirm DALI Group 1 returns to Scene 1 (20%) 7. Confirm GA 11/0/0 returns to 0 after 15-minute timer Zone 2 and Zone 3: repeat above procedure Disarmed state test: Write 0 to GA 11/5/0 (disarm) Trigger Zone 1 PIR — confirm NO alarm actions occur Confirm DALI remains at base level, no email sent Fail-safe test: Disconnect KNX bus power supply Confirm security zone floodlights turn ON (DALI SFL = 100%) Confirm non-security zones go to 20% (DALI SFL = 51) Restore KNX bus power — confirm normal operation resumes
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