IS200TDBSH6A GE Mark VI Discrete I/O Simplex Terminal Board

The GE IS200TDBSH6A is a Discrete Simplex Terminal Board. Acting as a physical interface, it connects logic signals from various field-based discrete sensors (such as pressure switches, temperature switches, and valve position signals) to the control system. Simultaneously, it converts the controller's logic commands into dry contact outputs via onboard relays to drive external actuators like solenoid valves and contactors.

This model is the simplex counterpart to the TMR (Triple Modular Redundant) version, TDBTH6A, and is designed for non-safety-critical BOP (Balance of Plant) and auxiliary circuits. The model suffix "6A" is critical; it signifies 125V DC compatibility, featuring voltage dividers and metal-oxide varistors (MOVs) specifically designed for 125V transients--distinguishing it from the 24V version (suffix "H2A").

• Input Channels: 24 channels, group-isolated (dry contact compatible)
• Input Wetting Voltage: 100-145 V DC (nominal 125 V DC)
• Output Channels: 12 Form-C SPDT relays
• Contact Rating: 0.6 A @ 125 V DC / 3.15 A @ 24 V DC / 120 V AC
• Logic Power: +5 V DC (from PDIO pack)
• Field Power: External 125 V DC (user-supplied)
• Isolation Voltage: 1500 Vrms (channel-to-backplane)
• Operating Temperature: -30°C to +65°C
• Relative Humidity: 5-95% RH (non-condensing)
• Mounting: DIN rail or flat-surface mount

GE-EX2000.pdf

• Serving as a simplex alternative to the TMR version, this model eliminates the need for TMR hardware in non-critical loops, reducing costs by approximately 50% compared to the TMR version while also lowering cabinet costs and spare parts inventory.
• It directly supports the 125V DC field devices commonly found in power plants, eliminating the need for external signal converters and simplifying system architecture.
• The design utilizes discrete components rather than high levels of integration, offering greater flexibility for future maintenance and the replacement of specific components.
• Designed for a wide industrial temperature range, it withstands the harsh operating environments of power plants. It undergoes burn-in testing prior to shipment, ensuring high reliability and durability.
• It supports online hot-swapping and uses onboard EEPROM to automatically identify channel types, allowing any terminal block to be replaced in just about 3 minutes.

1. Periodically inspect the integrity of the conformal coating to prevent circuit board short circuits caused by chemical corrosion or physical damage
2. Utilize the system's built-in hardware filtering and noise suppression diagnostic functions to regularly monitor input/output signal quality and identify potential sources of electromagnetic interference
3. During equipment downtime for maintenance, check the tightness of DIN rail clips or mounting screws and remove accumulated dust from the board surface to ensure optimal heat dissipation and insulation performance

At a large combined-cycle power plant, the engineering team upgraded the core I/O terminal to the IS200TDBTH6A model to prevent high-frequency noise from triggering false shutdown alarms.

Thanks to the unit's superior hardware filtering and 12V RMS AC voltage suppression capabilities, high-frequency noise was effectively isolated, raising signal transmission accuracy to 100%.

Following the upgrade, the plant not only eliminated the risk of unplanned shutdowns caused by false alarms but also achieved precise control over auxiliary equipment through stable relay outputs, significantly enhancing the unit's overall operational efficiency and safety.