Description
Key Technical Specifications
| Parameter | Value |
|---|---|
| Manufacturer | GE |
| Model | IS220PDIOH1B |
| Assembly Number | 336A5026ADP6 |
| Product Type | Discrete Input/Output I/O Pack |
| Series | Mark VIe / Mark VIeS |
| Digital Inputs | 24 optically isolated inputs |
| Relay Outputs | 12 Form-C mechanical relays |
| Network Interface | Dual 10/100Base-T Ethernet (IONet) |
| Input Isolation | 1,500 VAC optical isolation |
| Input Filter | 4 ms hardware filter |
| Typical Output Response | Approximately 4 ms |
| SOE Support | 1,000 Hz Sequence of Events recording |
| Compatible Terminal Boards | TDBSH2A, TDBSH8A, TDBTH2A, TDBTH8A series |
| Operating Temperature | -40 °C to +70 °C (H1B revision) |
| Diagnostics | Relay monitoring, fuse monitoring, wetting-voltage detection, terminal-board ID recognition |
The H1B revision improves the environmental operating range compared with earlier H1A hardware while maintaining compatibility with the Mark VIe architecture.
Product Introduction
The GE IS220PDIOH1B (336A5026ADP6) is a Discrete Input/Output I/O Pack designed for the GE Mark VIe and Mark VIeS Speedtronic turbine control systems. It acquires digital field signals from switches, limit switches, and interlocks while driving relay outputs for valves, contactors, alarms, and auxiliary equipment.
The module incorporates its own processor, diagnostics, and redundant Ethernet interfaces, allowing it to communicate directly with the Mark VIe controller over IONet. When installed on approved terminal boards, it supports high-speed sequence-of-events recording, relay feedback monitoring, and comprehensive fault diagnostics required in critical turbine applications.
- IS220PDIOH1B 336A5026ADP6
- IS220PDIOH1B 336A5026ADP6
Troubleshooting Quick Reference
| Symptom | Possible Cause | Relevance to this Part | Quick Check Method | Recommendation |
|---|---|---|---|---|
| I/O Pack not detected | Ethernet or terminal board connection fault | ✅ High | Verify both RJ45 IONet links and terminal board seating | Reseat module and inspect connectors |
| Multiple digital inputs remain OFF | Missing field wetting voltage | ✅ High | Measure wetting voltage at input terminals | Restore field power before replacing module |
| Relay outputs fail to energize | External fuse or relay circuit fault | ✅ High | Check relay feedback diagnostics and output voltage | Verify field wiring and fuses |
| ATTN LED illuminated | Internal diagnostic fault | ✅ High | Read diagnostics in ControlST | Replace module only after confirming hardware fault |
| Intermittent communication | Network cable or switch issue | ⚠️ Medium | Check Ethernet link LEDs and network statistics | Verify IONet integrity |
| Incorrect input status | Wrong terminal board configuration | ⚠️ Medium | Confirm terminal-board ID and wiring | Install the correct compatible terminal board |
| Multiple I/O Packs offline | Controller or network failure | ❌ Low | Check adjacent I/O Packs and controller status | Diagnose system network before replacing PDIO |
Field Tip: A large percentage of reported PDIO failures are actually caused by missing wetting voltage, blown output fuses, or damaged field wiring. Before replacing the I/O Pack, verify the terminal-board ID, measure the field voltage under load, and review the ControlST diagnostics. These checks often pinpoint the real fault without changing hardware.
Frequently Asked Questions (FAQ)
Q1. What is the primary function of the IS220PDIOH1B?
It provides the interface between the Mark VIe controller and field devices by processing 24 discrete inputs and 12 relay outputs while communicating over the redundant IONet Ethernet network.
Q2. Which terminal boards are compatible?
The IS220PDIOH1B is designed to mount directly on compatible GE terminal boards, including TDBSH2A, TDBSH8A, TDBTH2A, and TDBTH8A families. Always verify the exact terminal-board revision before installation.
Q3. What improvements does the H1B revision provide?
Compared with earlier H1A hardware, the H1B revision supports a wider operating temperature range (up to 70 °C) while maintaining compatibility with existing Mark VIe applications.
Q4. Can I hot-swap the ?
Do not assume hot-swapping is permitted. Follow the GE maintenance procedure for your specific Mark VIe installation and isolate power unless the official documentation explicitly authorizes replacement under power.
Q5. Why is the assembly number 336A5026ADP6 important?
The assembly number identifies the exact manufacturing configuration. When ordering a replacement, verify both the model () and the assembly number (336A5026ADP6) to ensure electrical and firmware compatibility.
Q6. Is this module still available?
Yes, but it is considered a mature Mark VIe product. Most inventory available today consists of New Surplus or professionally tested surplus units backed by supplier warranty rather than current OEM production.
Q7. What should I verify before installation?
Experienced Mark VIe engineers recommend checking:
- Complete model number ()
- Assembly number (336A5026ADP6)
- Compatible terminal board
- IONet Ethernet connections
- Field wetting voltage
- Relay fuse status
- Hardware revision compatibility
- ESD protection during installation
Completing these checks before commissioning resolves most startup issues and minimizes unnecessary replacement of the I/O Pack.
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