ABB DSAI 155A 3BSE014162R1 Thermocouple Input Module

ABB DSAI 155A 3BSE014162R1 Thermocouple Analog Input Module

The ABB DSAI 155A (MPN: 3BSE014162R1) is a rack-mounted 14-channel differential thermocouple analog input module engineered for the ABB MasterPiece 200 / Advant OCS S100 I/O sub-rack architecture. Built for harsh industrial and marine control environments, the board interfaces low-level millivolt signals from various standardized thermocouple elements across critical monitoring points—including marine main engine exhaust gas monitoring, auxiliary engine cylinder head temperatures, turbocharger inlet/outlet temperature logs, boiler superheaters, and heavy chemical process lines.

The module incorporates an integrating dual-slope analog-to-digital converter (ADC) programmed to integrate signal lines across fundamental power line cycles (50 Hz / 60 Hz), providing superior common-mode and normal-mode line frequency noise rejection. In typical configurations, the DSAI 155A works alongside dedicated terminal units such as the DSTA 155 (field connection block housing the Pt100 cold-junction reference sensor) and DSTA 156 (housing reference calibration channels for continuous self-diagnostics and auto-zero tracking).

Model Details

• Manufacturer: ABB Automation
• Model Type: DSAI 155A
• Manufacturing Part Number (MPN): 3BSE014162R1
• Sub-System Architecture: S100 I/O System (Advant Controller 410, 450, MasterPiece 200 series)

Features

1. 14 Isolated Differential TC Channels: Processes 14 individual thermocouple pairs with galvanic isolation from system logic, plus integrated hardware channels dedicated to cold-junction compensation and internal self-calibration.
2. Active Integrating Dual-Slope A/D Conversion: Converts low-amplitude millivolt inputs while synchronizing integration windows to suppress 50/60 Hz electromagnetic grid hum and marine switchboard harmonic interference.
3. Dedicated Cold-Junction Compensation (CJC): Supports automatic external CJC through integrated Pt100 RTD sensing elements located directly on the DSTA 155 terminal block, preventing junction gradient errors.
4. Continuous Self-Diagnostics & Auto-Zero Adjustment: Communicates automatically with two reference channels to counteract component thermal drift and maintain calibration over wide ambient operating temperatures.
5. Rugged Marine-Grade Sub-Rack Form Factor: Direct eurocard slide-in mounting for S100 sub-racks with front-panel diagnostic indicators for bus communication, channel faults, and run status.

System Compatibility

• Process Controllers: ABB Advant Controller 410, Advant Controller 450 (AC410 / AC450), MasterPiece 200 / 2000.
• Sub-Racks: ABB S100 I/O Subrack (e.g., DSCR 114, DSCA series).
• Terminal Base Units: ABB DSTA 155, DSTA 156 connection units.
• Interconnecting Cables: DSTC 155 / multi-pair twisted shielded assembly.
• Control Software: Advant Master Software, ABB MasterAid 215, AMPL engineering station.

Applications

• Marine Main Engine Monitoring: Multi-cylinder exhaust gas temperature (EGT) deviation control on 2-stroke and 4-stroke marine diesel engines (MAN B&W, WinGD, Wärtsilä).
• Marine Turbocharger Protection: Continuous monitoring of turbine gas inlet, outlet, and charge air receiver temperatures.
• Auxiliary Boilers & Thermal Fluid Heaters: Flue gas diagnostics, steam header superheater, and burner zone surveillance.
• Power Generation & Offshore Turbines: Bearing metal temperature (embedded thermocouples), stator core temperature tracking, and turbine casing heat profiling.
• Refining & Petrochemical Processing: Multi-point reactor bed thermal mapping and furnace tube wall skin temperature feedback.

Part Number Cross-References

• ABB Model Code: DSAI 155A / DSAI155A
• ABB 12-Digit Part Number: 3BSE014162R1
• Associated Functional Units: DSAI 155, DSTA 155 (Termination Unit), DSTA 156 (Reference Unit)

Frequently Asked Questions

What causes all thermocouple channels on a DSAI 155A to display constant full-scale or zero-scale readings?

This issue typically indicates a failure of the cold-junction compensation channel on the DSTA 155 terminal unit, a loss of the backplane reference voltages (±12 V / ±15 V), or a missing cable link between the module and DSTA 156 reference unit. Verify the terminal block cable connections and measure backplane supply rail voltages.

Can the DSAI 155A accept 4–20 mA or high-voltage (0–10 V) analog signals?

No. The DSAI 155A is exclusively designed for low-level millivolt signals (-10 mV to +60 mV) directly from thermocouples. To process standard 4–20 mA process transmitters or high-level voltages in an S100 rack, specify the ABB DSAI 130 or DSAI 130A analog input modules.

Are the channels on the DSAI 155A individually isolated from each other?

The channels are configured as differential inputs with high common-mode rejection, and the entire module is galvanically isolated from the S100 internal system bus. However, the 14 thermocouple channels share common reference and diagnostic scanning circuits. Ensure field thermocouple junctions are isolated types (ungrounded junctions) to avoid inter-channel signal cross-talk when submerged in conductive fluids or metal wells.

Is the DSAI 155A directly interchangeable with the older DSAI 155?

Yes. The DSAI 155A (3BSE014162R1) functions as the direct, backward-compatible replacement for early revisions of the DSAI 155 board. It mounts into the identical S100 subrack slot and interfaces with existing DSTA 155 / DSTA 156 wiring blocks without modification to controller application software.