The GE IS200STTCH2A, also cataloged as the IS200STTCH2 Simplex Thermocouple Board, serves as the primary IS200STTCH2A Input Terminal Board utilized to execute thermocouple signal cold junction compensation and A/D conversion across Mark VI control platforms.

Suffix Breakdown & Model Matrix

• IS200: Standard Mark VI terminal board prefix.
• STTC: Identifies the board as a Simplex Thermocouple input termination module.
• H2: Hardware generation identifier denoting the specific circuit density and layout revision.
• A: Functional revision level indicating initial release architecture for the H2 series.

Hardware Specifications

Backplane Bus Communication and Firmware Compatibility

The IS200STTCH2A maintains deterministic backplane bus communication velocity to ensure high-accuracy temperature data acquisition. It performs localized cold junction compensation (CJC) for all 24 channels, transmitting linearized digital values to the host I/O processor. Firmware flash compatibility is governed by the associated I/O pack firmware; ensure the host controller supports the "2A" hardware configuration to maintain correct A/D conversion timing and scan rate synchronization. I/O density scaling on this board is optimized for high-channel count monitoring, providing consistent signal sampling without bus-level latency.

Frequently Asked Questions

Q: Does this board support redundant signal input?

A: The IS200STTCH2A is a simplex board. While it handles 24 channels, it does not inherently provide redundancy. For applications requiring TMR or dual-redundant inputs, separate input paths must be verified at the controller level to prevent single-point failures in the signal chain.

Q: How is cold junction compensation handled for thermocouples?

A: The board features integrated thermistors located near the terminal blocks to measure the cold junction temperature. This data is used by the I/O pack to apply the necessary compensation algorithm to the raw millivolt thermocouple inputs.

Field Installation Guidelines

• Ensure the control cabinet is de-energized before mounting the board to the DIN-rail assembly to prevent electrical damage to the backplane connectors.
• Use only industry-standard thermocouple extension wire matching the specific type (J, K, T, etc.) connected to the board terminals. Avoid using copper wire to prevent thermal EMF errors.
• Shielding must be terminated at the cabinet ground bus. Avoid daisy-chaining shield grounds, as this can introduce ground loops and increase noise floor on low-level millivolt signals.
• When seating the board, apply uniform pressure to the connector housing. Ensure all captive screws are engaged to maintain mechanical stability and proper pin-to-pin contact.
• Verify channel-to-channel isolation by measuring the common-mode voltage relative to the cabinet ground; high levels of common-mode interference may require additional signal filtering or isolation transformers.