DS3820STCA - Terminal Communication I/O Assembly Module

SPECIFICATIONS:

Part Number: DS3820STCA
Manufacturer: General Electric
Series: Mark IV
Product Type: Terminal Communication I/O Assembly Module
Number of relay channels: 12
Power supply voltage: 24 V dc
Power Requirements: +5 V dc, 6 A
Mounting: DIN-rail mounting
Technology: Surface mount
Operating temperature: -30 to +65�C
Size: 15.9 cm high x 17.8 cm
Availability: In Stock
Country of Origin: United States

FUNCTIONAL DESCRIPTION:

DS3820STCA is a Terminal Communication I/O Assembly Module manufactured and designed by General Electric as part of the Mark IV Series used in GE Speedtronic Control Systems. The Terminal Communication I/O Module (STCA) is the IONET master for the I/O cores. Each I/O core includes an STCA board. Signals are read from the various connectors, conditioned, and sent to the I/O Engine on the UCPB daughterboard via bus connectors J1 and J3. The signals are written to the COREBUS connectors on the QTBA or CTBA boards using the JEE connector. The Terminal Communication I/O Assembly Module serves as a critical interface for field I/O signal termination and communication within industrial control systems. Designed for use in GE Speedtronic and similar automation architectures, the module consolidates discrete and analog signal pathways into a structured terminal assembly, enabling efficient wiring, signal conditioning, and diagnostic access. It supports common industrial I/O standards such as 4�20 mA current loops and 0�10 V analog signals, as well as discrete logic and contact closure inputs/outputs, with provisions for isolation and surge protection. Built for harsh operating environments, the module incorporates robust shielding, grounding, and noise suppression features to ensure signal integrity and reliable performance under vibration, temperature extremes, and electrical interference.

STCA PULSE RATE INPUT CIRCUIT:

The STCA board scales and conditions pulse rate inputs obtained from the TCQC board. These signals come from magnetic pickup devices and are transmitted to the TCQC board via the QTBA, TBQB, and/or PTBA terminal boards. The core detects high-pressure shaft pulse rate inputs. The pulse rate inputs in each core are autonomous and serve different functions.

STCA SYNCH CHECK CIRCUIT:

The generator and bus voltage inputs are read from the TCQC board using the 19PL connector. Signals from the PTBA terminal board in the core are sent to the TCTG board through the JN connection. The signals are routed from the TCTG board's JDR/S/T connections to the JD connector on the TCQA board's core. The signals are routed back to the TCQC board in the core via the JE connector. The TCQC board scales and conditions the signals before sending them to the STCA board through the 19PL connector.

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FREQUENTLY ASKED QUESTIONS:

What is the primary function of the Terminal Communication I/O Assembly Module?

The Terminal Communication I/O Assembly Module acts as a field I/O interface that consolidates signal routing and communication between process sensors/actuators and the central control system. It provides termination, isolation, and signal conditioning for both analog and discrete I/O channels. The module also supports structured wiring and diagnostics to facilitate maintenance and system troubleshooting.

What types of I/O channels does the module typically support?

Depending on the assembly configuration, the module supports discrete (digital) inputs/outputs and analog inputs/outputs. Discrete channels typically handle TTL/CMOS logic levels or contact closures, while analog channels support current loop (4�20 mA) or voltage signals (0�10 V). The module may also support optional isolation and filtering to maintain signal integrity in industrial environments.

How does the module manage signal integrity and noise immunity?

The assembly includes shielding, grounding provisions, and isolation barriers to reduce electromagnetic interference (EMI) and ground loop issues. It may incorporate filtering components such as RC networks or transient suppression devices to protect against spikes and electrical noise. Proper termination and cable routing, along with these design features, ensure stable signal acquisition and control.

What communication protocols are supported by the module?

The module primarily functions as a terminal I/O interface and typically supports protocol-neutral wiring; however, it is commonly used in conjunction with GE Speedtronic control architectures that use proprietary communication backplanes or fieldbus interfaces. The exact supported protocol depends on the specific Speedtronic system and module variant. Verification of the module�s part number and system configuration is recommended for accurate protocol compatibility.