• Sophisticated Tx/Rx Upstream, Downstream Fault Detection
• One or Multiple Masters for Maximum Reliability
• Async Data Rates up to 38.4 Kbps
• Separate Broadcast/Respond Channels
• Multimode & Single Mode (850/1300/1550nm)
• Protocol Transparent
• 4, 8 or 12 Channels RS-232/422/485
• Anti-Streaming Capability
• Built-In Power Redundancy
• Local Dry Contact Alarm Relay
• Rackmount or Standalone
• Extend telephone lines with LT1900 RS-232 or Fiber Phone Extenders

Application

The LT2800 is frequently used to interconnect Remote Terminal Units (RTUs) or Programmable Logic Controllers (PLCs) in Utility substation SCADA Networks that require multiple channels. It is also used for similar connectivity applications in Traffic Control, Industrial Process Control and Security System Networks.

Description

Intended for Ring and Self-Healing Ring topologies, the LT2800 Multi-Drop Fiber Optic Multiplexer interconnects up to 12 devices with RS-232, RS-422, or RS-485 (2 or 4 wire) interfaces over single mode or multimode fiber optic cable. Data rates up to 38.4 Kbps are supported.

The LT2800 is designed for a "polled-response" (Slave/Master) type of communication network. A wide-range temperature version (-20°C to 70°C), Model LT2800T, is available for extreme environments.

Each unit provides two pairs of fiber interfaces and 4, 8 or 12 independent RS-232 and/or RS-422/485 channels. The RS-232 channels can be used for data or as telephone extensions with Model LT1900 RS-232 or Fiber Telephone Extenders. Optical signals are re-generated at each drop. Anti-Streaming is provided to prevent a single node failure (e.g. "babbling") from bringing down the entire network. Fiber optic connectors are ST or FC. Electrical connectors are RJ-11 female. Standard power is 12VDC. Optional power sources are 24VDC, -48VDC, or 115/230VAC with an external power cube.

The LT2800 is available in three basic configurations: Single Ring with one Master unit, Dual Ring with one Master unit, or Dual Ring with Multiple Master units. The most reliable configuration is the Multiple Master self-healing ring. This innovative configuration maximizes the reliability of a single Master because it can recover faults or failures in both rings in several different places.

One or two Master units (LT2800) and at least two Slave units (LT2801) are required to form a self-healing ring. Fault conditions are detected on both Tx and Rx, upstream and downstream, and automatically re-routed to maintain Ring integrity. Dry Contact alarms can be connected to RTUs/PLCs to help the Control Center pinpoint specifically where a fault has occurred.

For maximum reliability, the LT2800 is available in a Dual Master version (see above diagram ), which provides a backup Master Unit.

When a fault condition occurs, the backup Master will start polling the Remote units from the opposite direction. The primary and secondary Master units can be located anywhere on the fiber ring network.

The LT2800 offers several features that enhance network flexibility for installation, troubleshooting and expansion including:

• The ability to add additional channels to the network at any time without affecting the system.
• The ability to re-configure the network at any time, e.g. moving devices to different rooms.
• The ability to adapt to different power sources or interfaces.
• The ability to separate broadcast & receive signals to avoid interference if the self-healing function is activated.

Specifications