Unit Control Layer - GE Mark VIe System Manual

3.3 Unit Control Layer

The Unit Control layer or Unit Data Highway (UDH) provides the network connections that support continuous operation of
the process equipment, including controller sets (general-purpose, safety loops, turbine-specific, static starter, exciter) and
HMIs. The UDH is an Ethernet-based network that provides direct or broadcast peer-to-peer communications between a
controller set and an operator/maintenance interface. The controllers operate at a fundamental rate called the
which is configurable, and is dependant on the controller processor type, the amount of application code being run, and other
loads.
Mark VIe controllers and HMIs use the
data exchange) and HTTP (for configuration of pages). In addition,
download to the controller over the UDH. Alarms and capture buffer uploads (that feed trip logs) are also through the SDI
protocol.
Note Current controls systems network architecture has UDH, PDH, and MDH connections on a common set of network
switches and media trunks.
The UDH connections to the controllers and HMIs are unshielded twisted pair (UTP) Cat 5e from edge switches. This
redundant mesh architecture
comprise one logical network.
The following figure displays the UDH network with connections to the controllers and HMIs.
Mark VIe
Mark VIe
HMI
Historian
Mark VIe
Controller
Set
R S
86 GEH-6721_Vol_I_BP
EGD protocol to exchange real-time data, which on the UDH is based on UDP/IP (for
allows network connectivity even if one cable or switch is faulty. Redundant networks still
Unit Data Highway (UDH)
Mark VIe
Controller
T
Mark Stat
Wind Power
Converter
Unit Data Highway Example
GEH-6721_Vol_I Mark VIe and Mark VIeS Control Systems Volume I
SDI protocol is used by the ToolboxST application to
Mark VIeS Mark VIe
Controller
Controller
SIL 3 LS2100 e
Functional Static Starter
Safety Control
Public Information
frame
SecurityST
Cyber
Security
Management
System
Mark VIe
Controller
EX2100 e
Excitation
Control
rate,