Monitoring Layer - GE Mark VIe System Manual

Feature
Type of Network
Speed
Media and Distance
Number of Nodes
Protocols
Message Integrity
External Interfaces
* Fiber-optic cable provides the best signal quality, completely free of electromagnetic interference (EMI) and radio frequency
interference (RFI). Large point-to-point distances are possible, and since the cable does not carry electrical charges, ground
potential problems are eliminated.

3.5 Monitoring Layer

The monitoring data highway (MDH) is used to further partition the flow of data to individual assets, and can include
connection to GE Monitoring and Diagnostic (M&D) equipment: the On-Site Monitor (OSM) or Remote Services Gateway
(RSG). The data that is allowed to travel over the MDH is managed by two specially configured Cisco 2901 routers. The
same mesh architecture and trunks provide the MDH from the root to edge switches, then from special configured ports on the
edge switches to the OSM or RSG. Other devices may also be included on the MDH to meet customer requirements.
Connectivity to the RSG and OSM is designed during the plant requisition phase, so the MDH is not the only available
implementation of GE M&D equipment.
Note Refer to the figure Simplified Network
92 GEH-6721_Vol_I_BP
PDH Network Features
Description
IEEE 802.3 Ethernet in a mesh topology
100 megabit per second or with 1000 megabit per second trunks interconnecting switches
Ethernet 100Base-TX is used for switch to controller/device connections. Cable is CAT 5e
compliant. Distance is up to 100 m (328 ft). * Fiber-optic connections, Ethernet 100FX, 1000SX,
1000 LX are used for distances of 2 km (1.24 mi), 550 m (1804.46 ft), and 5 km (3.11 mi),
respectively.
Up to 1024 nodes supported
Ethernet-compatible protocol, typically TCP/IP-based. Use GSM, OPC UA, or Modbus over
Ethernet for external communications.
32-bit cyclic redundancy code (CRC) appended to each Ethernet packet plus additional checks in
protocol used.
Various third-party interfaces are available; GSM, OPC UA, and Modbus are the most common.
Hierarchy.
GEH-6721_Vol_I Mark VIe and Mark VIeS Control Systems Volume I
Public Information