In the field of process control, Honeywell's Local Control Network (LCN), as a classic control network architecture, has been running globally for decades. With the evolution of industrial network technology, Honeywell has launched the Expert Local Control Network (ELCN), which migrates classic LCN systems to modern Fault Tolerant Ethernet (FTE) platforms, enabling users to efficiently upgrade and extend the system's lifecycle while retaining existing control strategies, field wiring, historical data, and graphical interfaces. This article will provide a comprehensive and in-depth professional interpretation of ELCN's system architecture, hardware platform, migration strategy, capacity limitations, and compliance certification.
Product positioning and technical background
Expert LCN is a fault-tolerant Ethernet version of the classic coaxial cable LCN. Its core goal is to support the gradual and lossless migration of LCN nodes to ELCN nodes. During this process, the node numbers, logical roles, control strategies, and application functions of the original LCN system remain unchanged, and users can complete the system upgrade in stages without affecting production operations.
The ELCN system consists of two main components:
ELCN Bridge: As a communication bridge between classic LCN and ELCN, it achieves bidirectional conversion between LCN messages and Ethernet messages. Bridges must be deployed in the form of redundant pairs.
ELCN node: an upgraded LCN node with a hardware platform of Universal Embedded Appliance (UEA) or virtual machine, running the same functional image as the original LCN node, communicating through FTE network, and no longer relying on coaxial cables.
After all LCN nodes have completed the upgrade, the ELCN bridge can be removed as the final step and its hardware can be reused as a spare.
System architecture and node types
1. Overview of overall architecture
The core feature of the ELCN system architecture is the mixed coexistence of LCN and FTE. In the initial stage of migration, redundant ELCN bridges simultaneously connect the classic LCN coaxial network and ELCN's FTE network to achieve dual network interconnection. The original LCN nodes (such as NIM, AM, EPLCG, EHB, NG, etc.) are gradually replaced with ELCN nodes based on UEA or virtual machines, while the original Windows based nodes (ESVT, ES-T, ACE-T, E-APP) are migrated to virtualization platforms or bare metal PCs.
2. ELCN Node Types and Platforms
ELCN nodes can be classified into the following categories based on their functions and platforms:
Node Type Platform Description
ELCN bridge UEA (hardware) redundant deployment, connecting LCN and FTE
ESVT (Expert Server TPS) virtual machine/x86 server running Windows Server 2016
ES-T (Expert Station TPS) virtual machine/x86 server running Windows 10 or Server 2016
ACE-T (Application Control Environment) virtual machine/x86 server running Windows Server 2016
E-APP (Expert Application Platform) virtual machine/x86 server running Windows Server 2016
HM (History Module) virtual machine/x86 server running Windows Server 2016
ENIM (Enhanced Network Interface Module) UEA/Virtual Machine replaces traditional NIM
AM (Application Module) UEA/virtual machine supports redundant configuration
EPLCG (Enhanced Programmable Logic Controller Gateway) UEA/Virtual Machine * replaces traditional PLC gateway
EHB (Expert Hiway Bridge) UEA/Virtual Machine Connection C300 Controller
NG (Network Gateway) UEA connects to Plant Information Network (PIN)
*Note: Virtual EPLCG is only used for engineering platforms (Open VEP) and does not support production environments.
Detailed explanation of hardware for general embedded devices
The Universal Embedded Device (UEA) is the core hardware platform of the ELCN system, which adopts a 1U high, 19 inch rack mounted design and supports dual module parallel installation. UEA consists of two main sub components:
1. Processor Module
Located at the front end, it includes a processor, user interface display screen, button controls, power supply, and fan.
Provide a 4-line x 20 character LCD display screen for status display and configuration.
Equipped with a five key navigation control (four directional keys+confirm key) and a three position key switch:
Location C: Configuration mode, allowing device configuration and restart
R1 position: Operation mode 1, read-only control
R2 position: Operation mode 2, read-write control
Front panel LED indicator light:
Green: Power supply is normal
Red: Fault
Amber: Warning
Green: Normal operation
Blue: Not configured or not loaded status
2. Termination Assembly
Located at the backend, providing all external cable connection interfaces, including:
Ethernet ports: 5 (2 uplink, 2 downlink, 1 redundant link), all 100Mbps, RJ45 interface, supporting automatic crossover
MAU interface: 2 Mini D-type interfaces for connecting media access units (MAUs) of LCN coaxial cables
Diagnostic LED: Each port is equipped with a link/activity indicator light (green) and a rate indicator light (yellow)
For the terminal components of EPLCG models, the port configuration varies: