IS220PDOAH1B, REV C - Discrete Contact Output I/O Module

SPECIFICATIONS:

Part Number: IS220PDOAH1B, REV C
Manufacturer: General Electric
Series: Mark VIe
Number of Channels: 24
Inputs: 125 V dc, 15A
Input Impedance: 4-20 mA
Input Converter Resolution: 16-bit A/D Converter
Product Type: Discrete Contact Output I/O Module
Output Fuses 12 fuses: 250 Volt, 15 A
Output Converter: 12-bit
Temperature Operating: -30 to +65 °C
Memory: 128 MB of flash memory
Ethernet: 10BaseT/100BaseTX (RJ-45)
Microprocessor: Intel Celeron 300 MHz
Size: 8.26 cm high x 4.19 cm
Technology: Surface Mount
Repair: 3-7 Days
Availability: In Stock
Weight: 2 lbs
Country of Origin: United States
Manual: GEH-6721D

FUNCTIONAL DESCRIPTION:

IS220PDOAH1B, REV C is a Discrete Contact Output I/O Module manufactured and designed by General Electric as part of the Mark VIe Series used in GE Distributed Turbine Control Systems. The PDOA pack functions as the electrical interface between one or two I/O Ethernet networks and a discrete output terminal board within the Mark VIe control system. It is equipped with a processor board that is standard across all Mark VIe distributed I/O packs, ensuring consistency and interoperability within the system. Additionally, it integrates a specialized acquisition board that is designed specifically for discrete output operations, enabling accurate signal acquisition and processing. The pack can control up to 12 relays, while also accepting feedback tailored to the terminal board type. Depending on the application, it supports both electromagnetic relays, compatible with TRLYH1B, TRLYH1C, TRLYH1D, and TRLYH1F terminal boards, as well as solid-state relays, which are supported with TRLYH1E terminal boards. This flexibility allows the pack to be deployed across a wide range of turbine and industrial control requirements.

In terms of connectivity and diagnostics, the PDOA provides robust options to ensure reliable system performance. Inputs are received through dual RJ45 Ethernet connectors, enabling redundant or primary network configurations, along with a three-pin power input for stable operation. The output is managed via a DC-37 pin connector, which establishes a direct link with the corresponding terminal board connector for seamless communication and control. For system monitoring and troubleshooting, the pack is equipped with visual indicator LEDs that provide real-time diagnostic feedback on operating status and fault conditions. Additionally, it includes a local diagnostic serial communication option accessible via an infrared port, giving technicians the ability to perform detailed checks and maintenance activities without disrupting system operations.

COMPATIBILITY:

The PDOAH1B pack is designed to be highly versatile, offering compatibility with six different types of discrete (relay) output terminal boards. This includes both TRLY series terminal boards and SRLY series terminal boards, which are commonly used in Mark VIe systems for reliable relay control and feedback functions. These boards support a range of applications requiring either electromagnetic or solid-state relay configurations, providing flexibility to meet specific control requirements. However, it is important to note that the PDOAH1B is not compatible with the DIN-rail-mounted DRLY terminal boards, which utilize a different mounting and connection standard. This distinction ensures that users select the appropriate terminal board type when integrating the PDOAH1B into their control system architecture, maintaining proper functionality and system reliability. The following table gives details of the compatibility:

• Simplex uses one I/O pack with one or two network connections.
• Dual uses two I/O packs with one or two network connections.
• TMR uses three I/O packs with one network connection on each.

INSTALLATION:

• Install the PDOA I/O pack into the terminal board connectors – For simplex configurations, a single PDOA I/O pack is sufficient and can be directly plugged into the appropriate terminal board connector. In triple modular redundancy (TMR) setups, three PDOA I/O packs are installed to ensure redundancy and fault tolerance. Each pack interfaces directly with the terminal board, allowing reliable signal transfer and control of the discrete outputs.

• Mechanically secure the I/O packs – Once inserted into the terminal board, the packs should be firmly secured using the threaded studs located adjacent to the Ethernet ports. These studs slide into a mounting bracket designed specifically for the type of terminal board being used. Proper mechanical securing ensures that the packs remain stable during operation and prevents movement that could compromise electrical connections.

• Adjust bracket to avoid stress on the DC37 connector – The mounting bracket position should be adjusted carefully so that no right-angle or bending force is applied to the DC37 connector that links the pack to the terminal board. Misalignment or stress on this connector could lead to connector damage, intermittent connections, or signal integrity issues. Proper bracket alignment protects the physical and electrical integrity of the interface.

• One-time bracket adjustment – The bracket adjustment is typically required only once during installation. After the initial alignment, the setup should remain stable for the life of the product. This ensures long-term reliability without the need for repeated mechanical adjustments or maintenance.

• Connect Ethernet cables – Depending on the system configuration, plug in one or two Ethernet cables. The pack is capable of operating over either Ethernet port, providing network flexibility. In dual connection setups, the recommended standard is to connect ENET1 to the network associated with the R controller, which helps maintain proper communication and control synchronization across the I/O system.

• Apply power to the I/O pack – Power is applied by connecting the three-pin power connector located on the side of the pack. It is not necessary to disconnect power from the cable before insertion, as the I/O pack is equipped with inherent soft-start circuitry. This feature controls current inrush during power application, protecting the pack and associated circuitry from sudden surges and ensuring a smooth and safe start-up.

OPERATION:

The PDOA relay command signals condition and level-shift outputs to interface with control logic. Each output uses an open-collector transistor with a current monitor to detect activation and load connection. Status LEDs and monitor outputs provide feedback, turning off if the load is not detected. The pack features 28V power management with soft-start to limit inrush and fast current limiting to protect the system. The green PWR LED indicates normal operation, and it turns off if the current limit function is triggered until the issue is cleared.

• High-speed processor with RAM and flash memory
• Two fully independent 10/100 Ethernet ports with connectors
• Hardware watchdog timer and reset circuit
• Local ambient temperature sensor
• Infrared serial communications port
• Status-indication LEDs
• Electronic ID and the ability to read IDs on other boards
• Substantial programmable logic supporting the acquisition board
• Input power connector with soft start/current limiter
• Local power supplies, including sequencing and monitoring

RELAY COMMAND SIGNALS:

The PDOA relay command signals provide the initial stage of signal conditioning and level shifting, enabling the terminal board outputs to interface with the control logic. Each output employs an open-collector transistor circuit with an integrated current monitor that detects when the output is activated and properly connected to a load. Status LEDs and monitor outputs indicate when an output is active and connected to the terminal board. If the output is activated but the expected load is not detected, the status LED remains off and the monitor signal returns false.

WOC maintains the largest stock of OEM replacement parts for GE Distributed Turbine Control Systems. We offer repair services for faulty boards as well as supply unused and rebuilt boards, all backed by a warranty. Our team of experts is available 24/7 to support your automation and OEM needs. For pricing, availability, or assistance with parts and repairs, please contact us by phone or email.

FREQUENTLY ASKED QUESTIONS:

What is the function of a discrete contact output I/O module?

A discrete contact output I/O module provides the electrical interface between the control logic and external loads, such as relays, solenoids, or indicators. It performs initial signal conditioning and level shifting to ensure proper logic-level compatibility. Each output is typically implemented using an open-collector transistor with current monitoring, enabling reliable detection of output activation and load connection.

How many outputs can a module control?

The module can control up to 12 discrete outputs, depending on the specific model and system configuration. Each output is independently monitored to ensure it has successfully energized the connected load. This configuration allows precise status reporting and isolation of individual output failures without affecting the remaining channels.

What types of relays are supported?

The module supports both electromagnetic relays (TRLYH1B, C, D, F series) and solid-state relays (TRLYH1E series). This allows compatibility with a wide range of load types and operational requirements. The selection of relay type affects activation response, current rating, and switching speed, which must be considered during system design.