Application Scenarios

In a large chemical plant’s distributed control system (DCS) upgrade, the existing ABB Advant OCS needs to integrate new third-party motor control centers (MCCs) that communicate via PROFIBUS-DP, while legacy PLCs still use MODBUS Plus. The ABB SNAT1451​ is installed in a remote I/O rack as the communication head module. It acts as a dual master, simultaneously polling data from the PROFIBUS MCCs and the MODBUS Plus PLCs, consolidating the information onto the ABB Module Bus for the main controller. This setup resolves the pain point of protocol incompatibility, eliminating the need for costly additional gateways and reducing system complexity, thereby ensuring smooth data flow and control command execution across mixed-vendor equipment.

 

Parameter

Parameter	Value / Specification
Manufacturer / Brand​	ABB​
Product Model​	SNAT1451​
Product Type​	Communication Interface Module / Digital I/O Board
Primary Function​	Dual Fieldbus Master (PROFIBUS-DP & MODBUS Plus) / I/O Interface
Compatible Systems​	ABB Advant OCS, MOD 300, S100 I/O, AC800M (associated)
Communication Protocols​	PROFIBUS-DP (Master), MODBUS Plus (Master), RS-485
Physical Interfaces​	DB9 connectors (typical for fieldbus), terminal blocks
Power Supply​	24 VDC​ (via backplane or external terminal)
Operating Temperature​	-20°C to +60°C​ (industrial standard)
Storage Temperature​	-40°C to +85°C
Dimensions (Approx.)​	~180mm x 100mm x 40mm (varies by specific variant)
Installation​	DIN Rail or Direct Panel Mount (within control rack)
Key Features​	Dual-protocol gateway, high noise immunity, modular design

 

 

Technical Principles and Innovative Values

• Innovation Point 1: Dual-Protocol Master Gateway.​ The SNAT1451‘s standout innovation is its integration of two major industrial fieldbus protocols (PROFIBUS-DP​ and MODBUS Plus) on a single board, each operating as a master. This architecture allows a single control node to actively manage and synchronize data from two entirely different network ecosystems without requiring an external protocol converter, reducing latency, cabinet space, and system cost.
• Innovation Point 2: Deterministic Data Routing.​ The board is designed for real-time performance. It handles the token-passing mechanism of PROFIBUS and the peer-to-peer messaging of MODBUS Plus concurrently, ensuring that critical process data from both networks is time-sliced and made available to the host controller (e.g., AC800M or Advant Controller) with minimal delay, which is vital for closed-loop control applications.
• Innovation Point 3: Flexible Role Configuration.​ Beyond communication, certain variants of the SNAT1451​ serve as high-density digital I/O or signal conditioning boards. Their design often includes configurable input filters and output drivers, allowing them to interface directly with a wide range of field devices (sensors, actuators) in harsh environments, providing signal isolation and noise rejection to ensure data integrity.

 

Application Cases and Industry Value

Case Study: Power Plant DCS ModernizationA combined-cycle power plant was extending its control system to include new gas turbine auxiliaries from a third-party vendor that used PROFIBUS-DP. The existing balance-of-plant controls relied on a legacy ABB system with MODBUS Plus​ networks. Instead of installing separate gateways and adding network complexity, engineers utilized ABB SNAT1451​ modules in the existing S100 I/O racks. The modules were configured as masters, seamlessly integrating the new turbines’ data into the main DCS. This approach saved over 30% in integration costs compared to a multi-gateway solution and reduced the network commissioning time by weeks, demonstrating the board’s value in extending the life and capability of legacy infrastructure.