In commercial buildings — offices, hotels, shopping centres — the HVAC and BMS layer typically runs on BACnet/IP (ASHRAE 135), while the smart building automation layer uses KNX. Bridging these two worlds traditionally required custom middleware or expensive proprietary gateways. The Intesis IN701KNX (now branded as HMS Industrial Networks INBACKNX1000000) solves this cleanly: it acts as a BACnet/IP Server and KNX TP client simultaneously, translating BACnet objects (Analog Value, Binary Value, Multi-State Value) to KNX group addresses in both directions, without programming — only configuration tables.

IN701KNX hardware and connection

The IN701KNX is a DIN-rail device (2 modules wide) with: 1 × KNX TP screw terminal (9600 baud, 29V bus), 1 × RJ45 Ethernet (10/100 Mbps, static IP), 1 × USB-B configuration port (for IntesisBox MAPS software, Windows), 24V DC auxiliary power supply (separate from KNX bus). Connection in panel: KNX bus: two-wire connection to KNX TP line (+ / -), polarity marked. Ethernet: connect to building LAN switch — same VLAN as BACnet/IP controller/BMS server. Static IP: assign manually via MAPS software (recommended: 192.168.x.x, avoid DHCP for gateways). The gateway requires ETS6 individual address assignment: connect KNX programmer to KNX TP line, run ETS6 assignment (IN701KNX appears as standard BCU). Note: the device has no ETS application program — it uses MAPS software exclusively for KNX group address configuration.

IntesisBox MAPS software configuration

MAPS is a free Windows application from HMS/Intesis for configuring all IntesisBox gateways. Download: intesis.com/downloads. Connect MAPS to IN701KNX via USB or IP. Project setup: create new project, select IN701KNX model, set KNX individual address, set BACnet device instance number (must be unique across BACnet network — use a fixed convention, e.g., 10001 for gateway 01), set BACnet/IP port (default 47808 / 0xBAC0). Signal configuration table: the core of MAPS configuration is a row-per-signal table mapping BACnet objects to KNX group addresses. Each row: Signal name (descriptive label), BACnet object type (AV = Analog Value, BV = Binary Value, MSV = Multi-State Value), BACnet object instance (number 0-9999), BACnet present value data type, KNX group address, KNX DPT, polling interval (for BACnet read), write direction (BACnet → KNX, KNX → BACnet, or bidirectional). Maximum signals: IN701KNX supports 1,000 bidirectional signals (upgrade licences available for larger counts).

Practical HVAC integration example: VAV AHU

Air handling unit (AHU) controller: Siemens Synco 700 RLU220 (BACnet/IP controller). KNX layer controls: room occupancy (from PIR sensors), lighting scenes, blind positions. Integration requirement: KNX occupancy → BACnet AHU setpoint change; BACnet supply air temperature → KNX display. IN701KNX mapping table: Row 1: Signal "Room Occupied", BACnet AV 001, Present Value, KNX GA 0/1/5 (DPT 1.002, 0=unoccupied, 1=occupied), Direction KNX→BACnet. Polling: N/A (write on KNX change). BACnet write: when KNX sends 1 on GA 0/1/5, IN701KNX writes BACnet AV 001 Present Value = 1.0 → Synco 700 interprets as occupied → switches from economy setpoint (18°C) to comfort setpoint (21°C). Row 2: Signal "Supply Air Temp", BACnet AV 050, Present Value, KNX GA 9/1/0 (DPT 9.001 = temperature, 2-byte float), Direction BACnet→KNX. Polling interval: 30 seconds. IN701KNX reads BACnet AV 050 every 30s, scales to DPT 9.001, writes to KNX GA 9/1/0 → Gira X1 visualises supply air temperature on floor plan.

BACnet object type to KNX DPT mapping

Standard mapping conventions: BACnet Binary Value (BV, active/inactive) → KNX DPT 1.001 (1-bit, 0/1). BACnet Analog Value (AV, floating point) with temperature: → KNX DPT 9.001 (2-byte float, Celsius). BACnet Analog Value with percentage (0-100%): → KNX DPT 5.001 (1-byte unsigned, 0-255, scaled by MAPS to 0-100%). BACnet Multi-State Value (MSV, integer states): → KNX DPT 5.005 (1-byte unsigned, state 1-253) or DPT 17.001 (1-byte scene number). BACnet Analog Output (AO, writable): usually used for actuator commands from BMS → KNX actuator, direction BACnet→KNX. Scaling: MAPS has a linear scaling function for each row — Analog Value raw range → KNX DPT range. Example: BACnet AHU fan speed 0.0-10.0 → KNX DPT 5.001 (0-100%): scale = ×10.

BACnet discovery and IN701KNX as BACnet server

The IN701KNX runs as a BACnet/IP server — it responds to BACnet WhoIs broadcasts and ConfirmedPropertyRequest from BACnet clients (BMS workstations, Siemens Desigo CC BACnet client). Each signal in MAPS becomes a BACnet object accessible from the BMS: the BMS adds IN701KNX as a BACnet device by IP address → reads its object list → sees AV 001, AV 050, BV 001 etc. → subscribes to COV (Change of Value) notifications for real-time updates (no continuous polling needed for fast-changing values). For BMS integration: Siemens Desigo CC → BACnet driver → Add device → IN701KNX IP address, device instance number → auto-import object list → bind to Desigo CC alarms and trends. Schneider EcoStruxure Building Operation: same process — BACnet device IP scan → IN701KNX visible as BACnet server → bind objects to EBO graphics and alarm pages.

Commissioning and validation

Validation steps: 1. KNX direction test — use ETS6 Group Monitor: write DPT 1.001 value 1 to GA 0/1/5 → verify MAPS diagnostic shows "KNX telegram received, writing BACnet AV 001 = 1.0". 2. BACnet direction test — from BACnet client (use Yabe BACnet Explorer, free): write AV 050 Present Value = 22.5 → verify ETS6 Group Monitor shows DPT 9.001 value 22.5 on GA 9/1/0. 3. Polling test — for status signals (BACnet→KNX): observe ETS6 Group Monitor for 30-second polling cycle; verify BACnet value changes are reflected in KNX within one polling interval. 4. IN701KNX diagnostic LED: green = normal, amber = KNX bus error, red = BACnet communication failure. MAPS real-time view shows live values for all signals — use during commissioning to spot incorrect scaling or wrong object instance numbers.