Description

GE IS410STCIS2A / IS400STCIS2AFF Product Description

Key Technical Specifications

The STCI board is specifically the 24 VDC member of the STCI family. GE also lists the IS410STCIS4A as the 48 VDC version, using the same IS420YDIAS1B I/O pack but a different field-wetting voltage range.

Product Introduction

The GE IS410STCIS2A is a simplex contact-input terminal board for the Mark VIeS Functional Safety System, providing a field interface for 24 discrete contact inputs. It works with the IS420YDIAS1B I/O pack, which processes the contact signals and communicates the input status to Mark VIeS safety control logic. The board’s floating 24 VDC wetting supply is designed to support ground-fault detection in the field input circuit.

The GE IS400STCIS2AFF designation is commonly paired with IS410STCIS2A in industrial automation inventory references. For procurement, the safest approach is to record both designations exactly as marked on the assembly or PCB. The functional identification should remain STCI, 24 VDC contact input, 24 channels, rather than relying on generic descriptions such as “discrete I/O module.”

IS410STCIS2A IS400STCIS2AFF

Application Scenarios & Field Pitfalls — The Engineer’s Perspective

Engineering Pain Point

A contact-input terminal board can look interchangeable with other Mark VIe/Mark VIeS digital-input hardware, but the field-wetting voltage and I/O architecture determine whether it belongs in the existing system. The IS410STCIS2A is specifically configured for 24 VDC contact inputs and should not be substituted with the 48 VDC STCI version simply because both use 24 input channels.

Typical Applications

• Turbine safety systems — monitoring permissives, trips, switches, and discrete status contacts.
• Gas and steam turbine control — acquisition of field contact states used by control and protection logic.
• Generator auxiliary systems — monitoring breaker, valve, pump, fan, and equipment status.
• Mark VIeS safety-system maintenance — replacement of failed or damaged contact-input terminal assemblies.

Technical Pitfalls

1. Verify the 24 VDC input architecture.
The IS410STCIS2A uses a nominal 24 VDC wetting supply with a specified 20–32 VDC range. The IS410STCIS4A is the 48 VDC variant with a 43–53 VDC range. These should not be treated as interchangeable field-voltage options.

2. The terminal board and I/O pack are separate parts.
The STCI assembly uses one IS420YDIAS1B I/O pack, ordered separately. A replacement terminal board without the appropriate I/O pack is not necessarily a complete functional module.

3. Do not confuse STCI with generic Mark VIe discrete I/O.
The STCI architecture is specifically designed for contact inputs in the Mark VIeS safety system. Other GE terminal boards may have similar channel counts but different input circuits, voltage classes, redundancy arrangements, or I/O packs.

4. STCI does not provide contact-input line monitoring.
GE specifies no contact-input line monitoring for this board. Do not assume that an open field wire will be diagnosed in the same manner as a terminal board that explicitly supports line monitoring.

5. The floating wetting source is significant.
The 24 VDC input source is floating to allow ground-fault detection. Field modifications that unintentionally reference the wetting circuit to cabinet ground can change the intended electrical behavior and should be reviewed against the original wiring design.

6. SOE capability should not be confused with controller scan time.
GE specifies a 1 ms SOE sample rate, while the control I/O scan rate is determined by the configured controller frame rate. These are different timing characteristics.

7. Confirm the board suffix before purchasing a board-only replacement.
The combination IS410STCIS2A / IS400STCIS2AFF is widely used in inventory references, but the physical PCB marking, hardware revision, terminal-board assembly, and installed I/O pack should be checked before declaring interchangeability.

8. Safety certification applies to the system architecture.
GE specifies the STCI module as safety-rated and compliant with IEC 61508. That does not mean that every field circuit connected to the board automatically constitutes a SIL-rated safety function; the complete safety architecture and application must be assessed.

Related Products

• IS420YDIAS1B — Mark VIeS YDIA discrete-input I/O pack used with the STCI terminal boards.
• IS410STCIS4A — 48 VDC STCI contact-input terminal board; same 24-input concept but different field-wetting voltage.
• IS400STCIS2A — board-level designation associated with the 24 VDC STCI assembly.
• IS410TBCIS2C — Mark VIeS contact-input terminal board with a different T-type architecture.
• IS410STAIS2A — simplex analog I/O terminal board; 10 analog inputs and 2 analog outputs, not a discrete contact-input replacement.
• IS410SRLYS2A — simplex relay output terminal board for discrete output applications.
• IS410TRLYS1B — relay-output terminal-board family supporting different redundancy arrangements.
• IS410TBAIS1C — TMR analog I/O terminal board for applications requiring a different analog redundancy architecture.

Procurement note: For an IS410STCIS2A / IS400STCIS2AFF replacement, verify the complete board marking, terminal-board revision, IS420YDIAS1B I/O pack, 24 VDC field-wetting arrangement, terminal-block style, and Mark VIeS application configuration. The most important distinction is that this is a 24-channel, 24 VDC simplex contact-input interface, not a generic digital I/O card.