The IS200VSVOH1B is a VME servo control board manufactured by General Electric as part of the Mark VI series used in gas turbine control systems. The four electrohydraulic servo valves that operate the steam/fuel valves are under the direction of the servo control (VSVO) board. Typically, two servo terminal boards are used to separate these four channels (TSVO or DSVO). The valve position (LVDT) is determined using a linear variable differential transformer.

The VSVO performs a cyclic control algorithm. Three cables are connected to the VSVO at the J5 plug on the front panel and at the J3/J4 connectors on the VME rack. the JR1 connector is used for the

TSVO to provide simplex signals, while the JR1. JS1 www.cniacs.com and JT1 connectors are used to fan out TMR signals. The external trip of the protection module is inserted into JD1 or JD2.

IS200VSVOH1B Installation

Close the VME’s processor rack.

Place the board in place, then hand press the top and bottom ties into the base of the edge connector.

Tighten the plus screws at the top and bottom of the front panel.

The cable connections to the TSVO terminal board are made at the lower J3 and J4 connectors of the VME rack. They are locking the connections in order to secure the cables. Start the VME rack and check the diagnostic indicators on the front panel.

IS200VSVOH1B Operation

LVDT position feedback, LVDT excitation, bi-directional servo current outputs, and pulse rate flow inputs are contained within the four channels of the VSVO.

The TSVO can provide excitation for up to six LVDT valve position inputs, and the TSVO accepts inputs from them as well. For each servo control loop, one, two, three or four LVDTs can be selected.

For applications measuring gas turbine flow, three inputs are provided. These signals are routed through the TSVO and sent directly to J5 on the front of the VSVO board. when power is lost, each servo output has a dedicated suicide relay which, when controlled by firmware, short-circuits the VSVO output signals to common and then returns to normal operation after a manual reset command.

Each servo’s output voltage, current, and suicide relay are monitored through the diagnostic function.