GE IS220PDIOH1A Mark VIe Discrete Input/Output Pack

The GE IS220PDIOH1A is a discrete input/output (PDIO) pack designed for the Mark VIe Speedtronic turbine control system. It provides the electrical interface between the I/O Ethernet network and a discrete I/O terminal board, supporting up to 24 contact inputs and 12 relay outputs. The assembly includes a local processor, a dedicated acquisition board, and two Ethernet communication ports.

Functional Description

The IS220PDIOH1A combines discrete input acquisition and relay output control in one I/O pack. Its processing board handles communication with the Mark VIe control network, while the acquisition board conditions field signals and manages discrete I/O operations.

The module receives input signals from field contacts through its associated terminal board and transfers their status to the controller. Output commands received over Ethernet are processed by the pack and delivered to the terminal board for relay operation.

Its two independent 10/100 Ethernet ports provide primary and secondary network connections. The pack also includes local diagnostic functions, processor monitoring, and status LEDs for identifying communication, power, and I/O conditions.

Terminal Board Compatibility

The IS220PDIOH1A is designed to connect directly to the following GE terminal boards:

• IS200TDBSH2A: Used for simplex PDIO configurations.
• IS200TDBTH2A: Used for triple modular redundant (TMR) PDIO configurations.

The terminal board determines the field contact input voltage arrangement and the associated relay interface. The TDBS configuration uses one PDIO pack, while the TDBT configuration supports up to three packs for TMR operation.

These specific terminal board combinations are also documented for hazardous-location applications. The terminal board, associated option boards, and complete installation must meet the applicable system and hazardous-area requirements.

Technical Specifications

Technical specifications are based on GE Mark VIe system documentation. Contact output ratings are electrical limits and must be checked against the specifications of the selected terminal board.

Signal Processing and Diagnostics

The 24 contact inputs use comparator-based signal conditioning with adjustable thresholds. Each input has filtering and hysteresis, while optical coupling and an isolated power supply provide isolation between the input circuits and control logic. The input channels are not individually isolated from one another.

The relay output section provides 12 command channels. Output monitoring circuits check relay command and load-related feedback, allowing the control system to identify discrepancies between commanded and monitored conditions.

Additional diagnostic functions include:

• Processor power-up self-tests.
• Ethernet port and internal power supply monitoring.
• Terminal board and acquisition board identification checks.
• Contact input wetting voltage monitoring.
• Non-responsive input detection.
• Relay command and feedback comparison.

The hardware scans input signals at a 1000 Hz rate for Sequence of Events (SOE) timestamping. Individual input and output points can be configured for SOE reporting.

Installation and Configuration

The IS220PDIOH1A mounts directly onto its selected terminal board through the DC-62 connector. Threaded studs beside the Ethernet ports secure the pack to the terminal board mounting bracket.

One or two Ethernet cables can be connected according to the system network configuration. For dual-network configurations, ENET1 is conventionally connected to the network associated with the R controller.

The I/O pack uses a built-in soft-start function to control power-on inrush current. ToolboxST software is used for hardware configuration and signal settings.

Field wiring must follow the applicable GE terminal board documentation, including conductor sizing, terminal assignments, and tightening torque requirements.

Frequently Asked Questions

Q: Which terminal boards are compatible with the IS220PDIOH1A?

A: The documented terminal boards are IS200TDBSH2A for simplex configurations and IS200TDBTH2A for TMR configurations. The correct selection depends on the required system redundancy arrangement.

Q: How many discrete signals can the IS220PDIOH1A handle?

A: The pack supports 24 contact input channels and 12 Form C relay output channels. It also provides relay and coil monitoring signals for output diagnostics.

Q: Can the IS220PDIOH1A operate in a TMR configuration?

A: Yes. When installed on the IS200TDBTH2A terminal board, the PDIO pack supports TMR configurations using three I/O packs, with one Ethernet network connection per pack.