IS200TBCIH1B

IS200TBCIH1B is a Contact Input Terminal Board manufactured and designed by General Electric as part of the Mark VIe Series used in distributed control systems. The 24-dry-contact input terminal board (TBCI) can be linked to two barrier-type terminal blocks. To excite the contacts, TBCI is linked with dc electricity. For surge and high-frequency noise protection, noise suppression circuitry is present at the contact inputs.

Mark VI Systems Connection

The terminal board of the Mark VI system is connected to the VME rack housing the VCCC or VCRC processor board by cables with molded connections. Systems in both simplex and TMR are supported. The TBCIH1B and TBCIH2B boards are identical to the TBCIH1C and TBCIH2C boards in terms of functionality and are compatible with Mark VI.

Mark VIe Systems Connection

The PDIA I/O packets in the Mark VIe system plug into the TBCI. A range of system configurations is supported by one, two, or three PDIA packs. For connector JT1 to be correctly mechanically aligned with the mechanical support of the I/O pack in Mark VIe, this board must be in the C version.

IS200TBCIH1B Installation

Wiring

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

Power Connections

According to the accompanying figure, plugs JE1 and JE2 are used to wire in the excitation voltage.

Cabling Connections

JR1 is used for simplex systems, and all three connectors are utilized for TMR systems. Depending on the type of Mark VI or Mark VIe system and the level of redundancy, cables or I/O packs are plugged in.

IS200TBCIH1B Operation

• Near the location of the signal entrance, filters decrease high-frequency noise and control surge on each input. The floating 125 V dc (100-145 V dc) supply from the turbine control powers the dry contact inputs on H1.
• Before feeding each contact input, the 125 V dc bus is currently restricted in the power distribution module. According to the specification table, the H2 and H3 variants employ lower voltages.
• The system controller receives the discrete input voltage signals from the I/O processor, which then passes them to optical isolators for group isolation. A transition threshold equal to 50% of the applied floating power supply voltage is established in the isolation circuits by the reference voltage.
• When the voltage drops below this level, the tracking is clamped to go no lower than 13% of the nominal rated supply voltage, forcing all contacts to signal open.
• Each input has two terminal points, one of which (a screw) serves as the positive dc source and the other of which (an input) serves as the return to the board.
• The first 21 inputs on each terminal board have a current loading of 2.5 mA per point, while the final three have a 10 mA loading to facilitate interfacing with external solid-state output devices.