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Rockwell Automation Publication 7000L-UM301F-EN-P - March 2020
Chapter 5
Component Definition and Maintenance
Optical Interface Boards
(OIB)
The Optical Interface Boards are the interface between the DPM and the Gate
Driver circuitry. The drive control decides which device to fire, and sends an
electrical signal to the OIB boards. The OIB board converts that electrical signal
to an optical signal, which is transmitted via fiber optics to the gate driver cards.
Typically, the Transmit ports are Grey and the Receive ports are Blue. The gate
driver accepts that signal and turns the device on and off accordingly. The
diagnostic fiber optic signals work the same way, but the source is the gate driver
boards and the destination is the drive control boards. Each OIB contains one
extra fiber optic receiver (RX7), which is used for temperature measurement.
Figure 302 - Optical Interface Board
The OIB boards are mounted directly on the Optical Interface Base Board
(OIBB) using two parallel 14-pin connectors for the electrical connection, and
plastic clips to provide the mechanical strength. There is one OIBB for the
inverter, and one OIBB for the rectifier device. The OIBBs are interfaced to the
DPM using two ribbon cables to connect to J11 and J12.
Each OIB board can handle the Firing and Diagnostic duplex fiber optic
connector for 6 devices, whether they are SCRs or SGCTs. Physically, on the
OIBBs, there is provision for 18 devices for the inverter and the rectifier. The top
OIB board on the OIBB is for the “A” devices, the middle OIB board on the
OIBB is for the “B” devices, and the bottom OIB board on the OIBB is for the
“C” devices. Test points for the OIB gating diagnostic and temperature feedback
signals are on the OIBB.
Each OIB board also has input RX7 for a signal from a Temperature Feedback
Board. The quantity and location of thermistor connections is dependant on the
drive configuration. Typically there is one temperature sensor from the Line
