DS200FCGDH1B is a Gate Distribution and Status Card manufactured and designed by General Electric as part of the Mark VI Series used in GE Speedtronic Control Systems. An interface board for a 6-pulse phase-controlled, non-reversing bridge is called the Gate Distribution and Status Card (FCGD). Through the VME backplane, it transmits feedback and diagnostic data after receiving SCR firing data from the DS200DSPC (DSPC, the VME processor) chip. The FCGD receives a multiplexed cell status signal from each bridge leg and decodes and de-tributes the cell gating signals for each bridge leg. Additionally, it takes in bridge feedback signals, scales them, and then transmits the voltage, frequency, and current status data back to the DSPC board.
BOARD FUNCTIONS:
SYSTEM CLOCK: The FCGD features a system clock register that produces firing commands and timestamp feedback values. This 16-bit up-counter ends when it reaches the hexadecimal value 0FFFFH and resets to 0.
SYSTEM RESET: During power-ups or hardware resets, the system reset signal sets all of the registers on the board to their starting settings.
SYSTEM HEARTBEAT: An electronic component's heartbeat serves as a periodic signal indicating that the component is still operational. This function is supported by the FCGD's system heartbeat register. The board-level heartbeat starts to count after the VME host CPU writes to it for the first time, and an IMOK-labeled green board-front LED turns on.
FIRING COMMANDS: A firing mask register with six entries that correspond to the six-cell strings in a bridge controls the fiber-optic firing signal transmitters. Up to six fiber-optic transmitters can be turned on simultaneously by the FCGD. The host CPU has the option to directly write data to the firing mask register across the VME bus connection.
VOLTAGE FEEDBACK FROM NATO: Over a 20-pin ribbon wire, the Voltage Feedback Scaling (NATO) board sends input signals to the FCGD (see Table 5). These signals include three ac voltages referred to ground through a local resistor, five attenuated analog voltage signals that correspond to plus and negative dc and five attenuated analog voltage signals. To maintain the output signals inside the 10 V range of the signal electronics, the input range is rescaled using the jumpers on NATO. The VME backplane has test points for the Va, Vb, Vc, Vp, and Vn signals.
ANALOG AND DIGITAL CONDITIONING: For analog voltage, current, and flux feedback, voltage-controlled oscillators are utilized. The VCOs are driven by the signals VA, VB, VC, VDC, IA, IC, FLUXBAR, and FLUXCBR (see Table 1). Additionally, six parallel Sigma-Delta converters that work with the VCOs are fed with the voltage and current signals.
