The Sauter modulo 6 is a Linux-based DDC (Direct Digital Control) building management system used extensively in hospitals, hotels, and large commercial buildings across Europe. Integrating a Sauter modulo 6 BMS installation with a KNX system enables room-level KNX devices (thermostats, presence detectors, lighting controllers) to interact bidirectionally with central HVAC plant controlled by the modulo 6 programme. The modu526 gateway is the official Sauter product for this bridge.

Sauter modulo 6 Hardware Overview

The modulo 6 controller (EY-modulo 6 series) is a compact Linux DDC controller with Ethernet, RS-485 Modbus RTU, and BACnet/IP. It is extended by EY-IO analogue and digital I/O modules connected via an internal bus. Typical configuration: four AI (analogue input) channels for temperature sensors and pressure transmitters, four AO (analogue output) channels for valve actuators and dampers, eight DI/DO channels for status and command signals. Multiple EY-IO modules can be chained to accommodate large plant rooms. The modulo 6 programme is written in CASE Engine, Sauter's IEC 61131-3 compliant programming tool, using function block libraries for standard HVAC sequences (PID control, cascade control, schedule-based setpoint adjustment).

modu526 KNX Gateway: ETS6 Integration

The modu526 is a DIN-rail KNX gateway that interfaces to the modulo 6 via BACnet/IP. Download the modu526 ETS6 application from the Sauter eProduct portal (requires Sauter partner login). Install the application in ETS6 via the catalogue import. In ETS6, configure the modu526: enter the BACnet/IP device instance of the modulo 6 controller, and the IP address. The modu526 supports up to 200 BACnet objects simultaneously mapped to KNX GAs. In the ETS6 modu526 parameter screen, browse the modulo 6 BACnet object list (auto-discovered), then assign KNX GAs to each selected object. Object type handling: BACnet Analog Value → ETS6 DPT 9.001 (temperature setpoints, measured values, valve positions in °C or %); BACnet Binary Value → ETS6 DPT 1.001 (on/off commands, status); BACnet Analog Output → ETS6 DPT 5.001 (valve position 0-100%).

Hospital Use Case: KNX Room Thermostat to VAV Box

In a hospital ward, a KNX room thermostat (e.g. MDT Glastaster II) measures room temperature and allows nursing staff to adjust setpoint within a permitted band. The thermostat publishes its setpoint GA (e.g. GA 5/2/3, DPT 9.001) to the KNX bus. The modu526 maps this GA to BACnet Analog Value 103 (room setpoint for ward 3) in the modulo 6. The modulo 6 CASE Engine programme reads AV 103 as the operator setpoint input to the VAV (Variable Air Volume) box PID control loop. The controller outputs to an AO channel driving the VAV damper actuator. Room temperature measurement from the modulo 6 temperature sensor is written back as BACnet Analog Input 203, which the modu526 maps to KNX GA 5/2/4 (DPT 9.001) for display on the room thermostat LCD and the nursing station tablet.

Bidirectional Integration: Occupancy to Lighting

The modulo 6 system in a hotel corridor manages occupancy detection via PIR sensors connected to DI channels. Occupancy status is published as a BACnet Binary Input (e.g. BI 5 = corridor occupied). The modu526 maps BI 5 to KNX GA 4/3/5 (DPT 1.002, occupancy). The DALI lighting controller subscribes to GA 4/3/5: when occupancy = 1, a KNX scene triggers corridor lighting to 100%; after a 300-second timer with no movement, the scene changes to 20% standby, then 0% after a further 120 seconds. This eliminates the need for separate KNX presence detectors in corridors already covered by the BMS PIR sensors.

CASE Engine: Reading KNX GAs from modulo 6 Programme

The CASE Engine FB_KNX_Read function block (available in the Sauter KNX library) allows the modulo 6 programme to read KNX GA values as inputs to control sequences. Example: FB_KNX_Read with KNX address parameter '8/1/0' reads the occupancy GA from a KNX presence detector. This occupancy value feeds a SetpointShift function block in the HVAC sequence, applying a -2°C setback when the room is unoccupied. This approach keeps the HVAC intelligence within the modulo 6 CASE programme while using KNX presence data as inputs — the cleanest architectural division.

Vision Center SCADA and BREEAM

Sauter Vision Center is the SCADA platform for modulo 6 installations. Drag modu526 BACnet objects onto the Vision Center floor plan to create live value overlays: room temperatures appear as coloured cells on the architectural drawing, valve positions as percentage bars, and fault statuses as colour-coded equipment icons. For BREEAM reporting, Vision Center's M&T (Measurement and Targeting) module generates monthly energy sub-metering reports from modulo 6 energy counter objects. If energy meters are connected directly to the modulo 6 via Modbus RTU, their data feeds into M&T automatically. For meters connected to KNX (ABB B24 with KNX interface), the modu526 maps the KNX energy GA back to a BACnet object that M&T can read.

Hotel Room: PMS Integration via BACnet

A hotel Property Management System (PMS) can signal room occupancy (check-in/check-out) to the modulo 6 via BACnet Write to a Binary Value object (BV 20 = room occupied). The modu526 maps BV 20 to KNX GA 5/0/0 (DPT 1.002, room occupied). A KNX scene controller responds: on check-in (GA = 1), execute scene 5 (welcome scene: lights to 60%, HVAC to 21°C setpoint, blinds to 50%). On check-out (GA = 0), execute scene 6 (energy save: lights off, HVAC to 18°C setback, blinds fully closed). This PMS-triggered automation reduces hotel room energy consumption by 25-35% versus a fixed schedule approach.

Commissioning Test

After ETS6 download and modu526 configuration: write a test setpoint value to a room thermostat GA from ETS6 Group Monitor. In CASE Engine online monitoring, verify the corresponding Analog Value reads the new setpoint value. Write an occupancy command from CASE Engine online to a BACnet Binary Input object and verify the KNX occupancy GA transitions in ETS6 Group Monitor within the modu526 polling interval (default 10 seconds). Confirm Vision Center floor plan updates accordingly.