IS200TBCIH2C - Conduction Sensor board

Functional Description

IS200TBCIH2C is a Contact Input Group Isolation terminal board developed by GE. 24 dry contact inputs are wired to two barrier-type terminal blocks on the Contact Input with Group Isolation (TBCI) terminal board. For contact excitation, TBCI is coupled with DC power. Surge and high-frequency noise are protected by noise reduction circuitry in the contact inputs.

TBCI supports simplex and TMR applications and works with VTCC/VCRC. TBCI is connected to the VME rack where the VCCC or VCRC processor board is placed by cables with molded plugs. Both the TBCIH B and TBCIH C variants of the board work with Mark VI and are functionally equivalent. The nominal voltage is 24 V dc.

Diagnostics

The following diagnostic tests are performed on components on terminal boards:

• The voltage of excitation is measured. The I/O pack/board sets and latches a diagnostic warning if the excitation falls below 40% of the nominal voltage.
• As a test, all of the terminal board's inputs are set to the open contact (fail safe) condition. Any input that fails the diagnostic test is forced into the failsafe mode, resulting in the creation of a fault.
• A fault is issued if the input from this board does not match the TMR voted value from all three boards.
• Each terminal board connector has its own ID device, which the I/O pack/board queries.

IS200TBCIH2C Specifications

• Number of channels: 24 contact voltage input channels
• Input filter: 4 ms Hardware filter
• Power consumption: On the terminal board, 20.6 W
• Configuration: On the board, there are no jumpers or hardware settings.

Installation

Wiring

Connect the wires for the 24 dry contact inputs to the terminal board's two I/O terminal blocks directly. Two screws hold these blocks in place, and they can be unplugged from the board for maintenance. Each block has 24 terminals that can accommodate wires up to #12 AWG. To the left of each terminal block is a shield terminal strip that is connected to the chassis ground.

Power Connection

Use plugs JE1 and JE2 to connect TBCI to the contact excitation voltage source.

Cabling Connections

Connect TBCI to the I/O processor using connector JR1 in a simplex system. Connect TBCI to the I/O processors in the TMR system using connectors JR1, JS1, and JT1. Depending on the type of Mark VI, Mark VIe, or Mark VIeS system and the level of redundancy, cables or I/O packs are plugged in.

Operation

Signal Filtering and Power Supply

On each input near the point of signal entry, filters decrease high-frequency noise and control surge. The dry contact inputs on H1 are powered by the turbine control's floating 125 V dc (100-145 V dc) supply. Prior to supplying each contact input, the 125 V dc bus is current limited in the power distribution module. As seen in the specification table, the H2 and H3 variants employ lower voltages.