DGC Brushless Excitation - Emerson Process Management

DGC Brushless Excitation
System Description
The IOICU receives and conditions digital input signals from the field in three ranges: 125 VDC, 15
VDC and 5 VDC and converts them to the 5 VDC logic states. Digital inputs are optically isolated.
The IOICU converts the logic states to dry relay contacts and provides the capability to “tristate”
each of the digital outputs as part of the redundancy features of the DGC.
3.3.d VME Power Supply
Each DGC channel is equipped with its own rack mounted, quad output, power supply module.
Each Power Supply is fed by two independent power sources; Station 125 VDC system and an
independent 120 VAC source.
Each Power Supply provides dedicated power to its respective channel of the DGC at +5 VDC, +12
VDC and -12 VDC. Each power supply also provides auctioneered +48 VDC to the IOICU
Backplane for distribution to the Field Interface Panel and the cooling fans.
3.3.e Network Hub Module
The Network Hub Module provides a hub for Ethernet communication with the DGC channels. The
two single board computers also use the network connection for inter-processor communications.
The network connection is also used by the DGC configuration software and optional SCADA
software.
3.4 Field Interface Panel
The Field Interface Panel (FIP) is a large printed circuit card with a purpose to provide simple and
reliable connections between the DGC computer and the field. The FIP connects to the IOICU
backplane using prefabricated ribbon cables.
FIP2 for WTA Retrofit Applications / FIP3 for Stand Alone Applications
The field terminations on the FIP are designed to accommodate the physical connections for two
distinctly different DGC applications. For the WTA Retrofit application, the FIP connects to the field
using four large AMP connectors, which are compatible with the existing WTA Regulator cable
harnesses. For all other applications, the FIP connects to the field using “euro” style terminal blocks
mounted on the periphery of the board.
The FIP is largely a passive device. The only active components mounted on the FIP are
interposing relays and LEDs that are assigned to some of the digital output circuits to accommodate
higher contact rating requirements.
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