IS220PSCAH1A Serial Communication Module | Mark VIe

The General Electric IS220PSCAH1A is a versatile Serial Modbus Communication I/O Pack for the Mark VIe distributed control system. This module acts as a critical gateway, providing robust serial communication interfaces and Ethernet connectivity for industrial automation and turbine control applications.

Core Technical Specifications

• Brand & Model: General Electric IS220PSCAH1A (Revision K)
• Series: Speedtronic Mark VIe Distributed Control System
• Module Type: Serial Communication I/O Pack (PSCA)
• Communication Ports: 6 individually configurable serial channels; 2 RJ45 Ethernet ports.
• Power Supply: 24/28 VDC input via 3-pin connector.
• Dimensions (HxWxD): 3.25" x 1.65" x 4.78" (8.26 cm x 4.19 cm x 12.14 cm).

Communication Capabilities & Protocols

• Serial Standards: Each of the 6 channels can be independently configured for RS-232, RS-422, or RS-485 (half-duplex).
• Modbus Support: Functions as a Serial Modbus Master and supports Ethernet Modbus on Simplex networks.
• Baud Rates: Configurable from 300 to 115,200 baud for serial communication.
• Data Flow: Handles both fixed I/O (for smart devices) and bulk Modbus I/O, transferring up to 9600 bytes/second to the controller.
• Cable Distance (RS-232): Supports distances up to 50 ft (15 m).

Hardware Integration & Installation

• Mounting: Plugs directly into a compatible serial communication terminal board (e.g., SSCA).
• Connectors: Features a DC-62 pin connector for the terminal board, dual RJ45 Ethernet ports, and a 3-pin power input.
• Secure Mounting: Includes threaded inserts for a mounting bracket to prevent stress on the main connector.
• Power Feature: Incorporates soft-start capability to control inrush current.
• Technology: Surface-mount construction with a common BPPC processor board.

Environmental & Operational Data

• Operating Temperature: -40°F to 158°F (-40°C to 70°C).
• Software Support: Requires ControlST software version V04.07 or later for configuration.
• Diagnostics: Front-panel LED indicators for status and comprehensive self-diagnostic tests.
• Isolation: Provides optical isolation for trip interlocks up to 1500 V.

System Role & Applications

• Primary Function: Serves as a communication interface between the Mark VIe controller's IONet and serial field devices or networks.
• Typical Use: Connects to smart pressure transmitters, drives (e.g., Kollmorgen), valves, and other Modbus-enabled equipment in turbine control and functional safety systems.
• System Architecture: Integral part of GE's Mark VIe and Mark VIeS systems for gas/steam turbines and other critical industrial processes.

Frequently Asked Questions (FAQ)

What is the main difference between the six serial ports?

The six ports are identical in hardware but can be independently configured in software for different electrical standards (RS-232, RS-422, RS-485) and communication parameters (baud rate, parity, data bits), allowing connection to a variety of devices from a single pack.

Can both Ethernet ports be used simultaneously?

Yes, both RJ45 ports are active. Standard practice is to connect ENET1 to the network associated with the R controller for redundancy, but the pack will operate over either port and automatically negotiate the connection.

How is this I/O pack configured?

Configuration is performed using GE's ToolboxST application. You add the PSCA module to the project, then define and configure each serial channel and Ethernet port for its specific protocol and device requirements.

What does "second-class I/O" mean for Modbus data?

It means Modbus data is transferred in bulk packages at defined intervals (e.g., 1 Hz or 4 Hz) rather than being individually processed every control frame. Coherency is maintained at the signal level, and system limit checking is not performed on these points.

What happens if a serial communication link fails?

The pack's diagnostics will detect timeouts. After three consecutive timeouts, a signal is marked unhealthy. After four, its value is cleared. Diagnostic alarms (e.g., 32-67, 72-107) are generated to alert operators to the communication fault.