GE EX2100 - Manual (Page 34)

2-14 •••• Chapter 2 Functional Description GEH-6632 EX2100 User’s Guide
Controller C
Controller C is only used with redundant systems. It is mounted in the control rack
and is physically similar to the M1 and M2 controllers, however, C is not responsible
for bridge firing and therefore does not contain an ESEL, or ACLA board.
Controller C receives the same feedback voltage and current inputs as the other
controllers and contains similar software. Its purpose is to monitor the active and
backup controllers (M1 or M2) and initiate appropriate protective responses in the
event the system conditions exceed the defined regulation boundaries. Input and
output signal voting takes place in all three controllers, which are linked in a Triple
Modular Redundant (TMR) controller configuration.
Each controller contains up to six boards, interconnected through the backplane as
shown in the simplified diagram of Figure 2-7.
ACLA
M1
DSPX
M1
ACLA
M2
DSPX
M2
DSPX
C
ISBus
To plant controls
Communication
across backplane
Serial
Modbus Serial
Modbus
DPM DPM
I/O I/O I/O
Ethernet Data Highway (EGD, Modbus)
Figure 2-7. Communication between Redundant Control Boards
Control Power Supplies
Redundant supplies provide
high reliability. Power for the controls come from the Exciter Power Distribution Module (EPDM).
This is supplied by a 125 V dc source and one or two 115 V ac sources. The ac
source is passed through an ac/dc converter (DACA) as shown in Figure 2-8. The
resulting 125 V dc is diode coupled with the other dc sources to create a dc bus that
feeds the control modules and gate pulse amplifier boards. Fused outputs from the
EPDM feed power to the EGPA boards, EXTB, and the Exciter Power Backplane
(EPBP). Each output has an LED indication and an on/off isolation switch.
The EPDM mounts on the left side of the Exciter Power Supply rack. Up to three
Exciter Power Supply Modules (EPSM) mount in the EPBP backplane and provide
logic level power to the controller(s). The EPSM s are fed by 125 V dc from the
EPDM, and generate supply voltages of +5 V dc, ±15 V dc, and +24 V dc. In