DDC Controller BACnet IP MS/TP 128 Points

128 Points. Dual BACnet Ports. Built-In Web Dashboard. The Intelligence at Every Mechanical Floor.

The Direct Digital Controller (DDC) is the field-level intelligence of a Building Management System — the device that reads sensors, computes control outputs, commands actuators, and executes the HVAC, lighting, and plant control sequences that determine how a building performs. A well-programmed DDC delivers the energy savings and occupant comfort that justify BMS investment; a poorly specified DDC becomes a maintenance burden that neither the facilities team nor the contractor can reliably support.

SSAL specifies DDC controllers with BACnet/IP and BACnet MS/TP dual communication, built-in web server, and 128 universal I/O points — providing a single, flexible field controller that adapts to the specific sensor and actuator count of each mechanical floor or plant room without forcing oversizing or undersizing compromises.

Key Features

128 Universal I/O Points (Configurable): 128 software-configurable input/output points — each point is configurable as analog input, digital input, analog output, or digital output through the controller software without hardware changes; eliminates the need for separate AI/DI/AO/DO module ordering for each application variant
Dual BACnet Ports — BACnet/IP + BACnet MS/TP: Primary BACnet/IP port communicates upstream to the BMS server/supervisory workstation over the building Ethernet network; BACnet MS/TP port operates as the trunk for downstream MS/TP field devices (VAV controllers, room units, expansion modules) — eliminates the need for a separate MS/TP router in multi-tier BMS architectures
Built-In Web Server: Access the DDC's live point values, trend logs, alarm list, and control sequences from any web browser on the building LAN — no dedicated engineering workstation software required for routine monitoring and fault investigation
12-Month Onboard Data Logging: Stores 12 months of 1-minute interval trend data for all 128 points in non-volatile flash memory — complete data history remains available locally even if BMS server communication is interrupted; energy management and fault diagnosis do not depend on continuous server connectivity
BACnet Advanced Workstation (B-AWS) Certified: The highest BACnet device profile — the DDC implements the full BACnet object and service set required for a supervisory workstation, not just a field device; enables peer-to-peer control logic between DDCs without routing through a central server
Graphical Function Block Programming: HVAC and plant control sequences are programmed using drag-and-drop graphical function blocks — maintainable by the client's facilities engineering team without requiring specialist BMS software skills
Structured Text (IEC 61131-3): For complex control logic, structured text programming provides programming language control — experienced BMS engineers can implement advanced energy optimisation algorithms and custom sequences
Onboard Alarm Management: Alarm generation, acknowledgement, and notification configuration is managed within the DDC — no BMS server dependency for alarm delivery to email, SMS, or SNMP monitoring systems
24VDC Backup Power Input: Dedicated UPS backup input maintains DDC operation and data logging during mains power failure — plant status and trend data are preserved through power interruptions
DIN Rail or Panel Mount: Standard DIN rail mounting in mechanical plant distribution boards; surface panel mount option for standalone enclosure installations

Technical Specifications

Parameter	Specification
Universal I/O Points	128 (software-configurable analog/digital input/output)
Analog Inputs	Up to 64 (configurable): 0–10V, 4–20mA, NTC, PT100, PT1000, DI pulse
Digital Inputs	Up to 64 (configurable): dry-contact, pulse counter
Analog Outputs	Up to 32 (configurable): 0–10V, 2–10V, 4–20mA
Digital Outputs	Up to 32 (configurable): triac, relay (24VAC/VDC)
Communication Port 1	BACnet/IP (Ethernet RJ-45, 10/100Mbps)
Communication Port 2	BACnet MS/TP (RS-485, 76.8kbps)
BACnet Device Profile	B-AWS (BACnet Advanced Workstation)
Web Server	Built-in HTTP/HTTPS (no additional software required)
Onboard Data Logging	12 months at 1-minute interval (all 128 points)
Non-Volatile Memory	Flash (data preserved through power failure)
Programming Environment	Graphical function block + IEC 61131-3 structured text
Firmware Update	Over-the-network (via BACnet/IP or web browser)
Backup Power Input	24VDC (for UPS connection)
Primary Power Supply	24VAC or 24VDC (±10%)
Power Consumption	≤15W (controller only, excluding I/O loads)
Operating Temperature	0°C to +55°C
Storage Temperature	−20°C to +70°C
Humidity	10–95% RH (non-condensing)
Mounting	DIN rail (EN 60715 35mm) or surface panel
Dimensions (W×H×D)	280mm × 190mm × 60mm (approx., base unit)
Weight (approx.)	1.8kg
Certifications	BACnet Testing Laboratories (BTL) B-AWS listed; CE; UL 916

Typical Applications

Multi-Tenancy Office Tower — Floor-by-Floor HVAC Control: One DDC per mechanical floor controls AHU, VAV boxes, chilled water and heating water zone valves, CO₂-demand-controlled ventilation, and lighting relay panels — 128 points typically accommodates a full floor plant complement without expansion modules
Hospital HVAC and Clean Room Control: Precise temperature and humidity control in operating theatres, clean rooms, and ICU areas; alarm escalation for critical parameter deviation; 12-month trend data for joint commission compliance documentation
Hotel Guest Room ACS — Central Plant Control: DDC controls central chilled water and heating water plant serving multiple floors; guest room unit local controllers (fan coil units) connect via BACnet MS/TP sub-bus to the floor DDC
Shopping Mall Energy Management: Central DDC monitors and controls all HVAC plant, lighting circuits, and escalators; built-in data logging enables energy consumption trend analysis without additional server infrastructure
Industrial Plant Utilities — HVAC and Process Cooling: Universal I/O accommodates the mixed instrumentation of industrial environments (PT100 temperature sensors, 4–20mA flow transmitters, relay outputs to variable-speed drives); structured text programming supports custom process control logic
Data Centre Environment Control: Precision temperature and humidity control for IT halls; redundant DDC configuration provides controller fault tolerance; BACnet/IP integration with the data centre infrastructure management (DCIM) platform

Compatibility & Integration

DDC controllers integrate with all major BMS supervisory platforms via BACnet/IP — Siemens Desigo CC, Honeywell EBI, Johnson Controls Metasys, Schneider Electric EcoStruxure. BACnet MS/TP sub-bus connects downstream room controllers, VAV box controllers, and I/O expansion modules. SSAL integrates DDC alarm outputs with fire alarm systems (BACnet integration), access control systems (occupancy-based HVAC setpoint adjustment), and metering systems (energy pulse count inputs) as part of intelligent building automation designs.

SSAL Supply & Support

Smart Safety & Automations Ltd. designs, programs, and commissions DDC controllers as part of complete BMS projects. SSAL's commissioning process includes point-by-point I/O verification, control sequence testing under simulated operating conditions, trend log setup, and alarm threshold configuration. SSAL provides as-built documentation including point schedules, control sequence descriptions, and BACnet device configuration reports. Annual Maintenance Contracts include control sequence performance review, trend data analysis for energy optimisation opportunities, and firmware updates.

Request a Quote

Intelligent building control from every mechanical floor. Contact SSAL for your BMS design.

Web: www.smartsafety.com.bd
Email: info@smartsafety.com.bd
Phone: +880-XXXX-XXXXXX
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Direct Digital Controller (DDC) — BACnet/IP & MS/TP (128 Points, Web Dashboard)

Product Summary