Key Technical Specifications
| Parameter | Specification |
|---|---|
| Product Model | IS220PAICH1A |
| Manufacturer | GE Energy / GE Boards & Turbine Control |
| Product Type | Analog I/O Pack (PAIC) |
| System Compatibility | GE Mark VI / Mark VIe IS200 |
| Power Supply | 24 VDC / 28 VDC (min 27.4 VDC) |
| Ethernet Ports | 2× RJ-45 (IONet) |
| Field Interface | DC-37 connector to terminal board |
| Compatible Terminal Boards | IS200STAIH1A, IS200STAIH2A, IS200TBAIH1C |
| Analog I/O Function | Analog input/output via terminal board (channel count varies by board) |
| Redundancy | Supports TMR (Triple Modular Redundant) architectures |
| Rack Mounting | 13-slot or 21-slot VME rack |
| Operating Temp. | -30°C to +65°C |
| Hazardous Location | Class I Div 2 Groups A–D; ATEX Zone 2 IIC |
| Certifications | UL E207685; UL DEMKO 12 ATEX 1114875X / 1102473X |
| Reference Document | GEI-100646 (installation instructions) |
Product Introduction
I’ve replaced enough GE turbine control packs in humid, vibrating equipment rooms to appreciate when a module just works. The IS220PAICH1A is GE’s analog I/O pack for the Mark VI and Mark VIe IS200 family — the kind of hardware you find in gas turbine, steam turbine, and critical process control cabinets where analog signals can’t afford to drift.It sits on a VME rack (13- or 21-slot), plugs directly into a terminal board via a DC-37 connector, and talks to the controller over dual IONet Ethernet ports. The PAIC handles analog input and output conditioning through the terminal board — IS200STAIH1A, IS200STAIH2A, or IS200TBAIH1C — which is where the actual channel count and signal types get defined. It supports TMR architectures, so in a triple-redundant setup, three of these packs vote inputs in software (SIFT) to mask a single-point failure. The -30°C to +65°C range and Class I Div 2 / ATEX Zone 2 approvals mean it’s rated for the kind of environments that eat consumer-grade hardware for breakfast.One thing to watch: the H1 revision is older. The newer IS220PAICH2A has documented specs (10 analog inputs, 2 current loop outputs), but the H1 channel configuration isn’t published as cleanly in public sources. Don’t assume the H1 matches the H2 pin-for-pin. Check your terminal board and your ToolboxST configuration before swapping.
Quality SOP & Tech Pitfalls
The Lab Report (SOP)
Every unit ships after:
- Visual and counterfeit check — housing, label revision (e.g., rev. F, rev. G), DC-37 connector pins, Ethernet port condition.
- Live bench test — apply 24/28 VDC via the 3-pin power connector, verify PWR/ATTN/LINK/TxRx LED behavior.
- IONet link test — confirm both RJ-45 ports negotiate and respond to a controller poll.
- DC-37 connector continuity check — verify pin integrity to the terminal board interface.
- Firmware/revision logging and anti-static bag sealing.
The Engineer’s Warning (Pitfalls)
Two mistakes will cost you a turbine trip. First, swapping an H1 for an H2 without checking the terminal board. The IS220PAICH2A has documented I/O assignments (10 analog inputs, 2 current outputs), but the H1 may differ. If your ToolboxST project expects H2 channel mapping and you drop in an H1, your analog readings will be garbage. Second, losing the IONet node assignment. In a TMR configuration, each pack has a specific network position. Plug it into the wrong IONet segment or swap ENET1/ENET2, and the voter will flag a communication fault. I once watched a combined-cycle plant chase a “bad pack” for four hours when the tech had simply crossed the two Ethernet cables. Don’t be that tech.Also: verify the revision suffix. “IS220PAICH1A” and “IS220PAICH1B” are different revisions with potentially different firmware and hardware.
Installation & Configuration Guide
- Pre-Installation ⚠️
- Follow proper LOTO on the turbine control cabinet.
- Photograph existing wiring, LED states, IONet cable positions (ENET1 vs. ENET2), and the DC-37 connector orientation.
- Note the revision code (e.g., rev. F, rev. G) on the old pack’s label.
- Removal
- Disconnect the 3-pin power connector.
- Unplug both IONet Ethernet cables and label them ENET1/ENET2.
- Remove the mechanical mounting bolts near the Ethernet ports.
- Gently pull the pack straight out of the DC-37 terminal board connector.
- Installation
- Verify the revision code matches the old pack. H1 and H2 are not automatically interchangeable.
- Align the DC-37 connector carefully and seat the pack firmly — do not force it at an angle.
- Reinstall the mechanical mounting bolts to prevent vibration loosening.
- Reconnect ENET1 and ENET2 to their original ports.
- Reconnect the 3-pin power connector.
- Power-On & Testing
- Apply 24/28 VDC and observe the LED sequence (PWR → LINK → normal operation).
- Verify IONet communication in ToolboxST.
- In a TMR system, confirm the new pack syncs and votes correctly with the other two channels.
- Cross-check analog readings against known field values before releasing the unit to service.
Compatible Replacement Models
| Replacement | Compatibility | Notes |
|---|---|---|
| IS220PAICH1A (same revision) | ✅ Drop-in | Exact match. Preferred for spare replacement. |
| IS220PAICH1B / IS220PAICH1BG | ⚠️ Revision dependent | Same family but different revision. May require firmware verification and ToolboxST compatibility check. Estimate 1–2 hours engineering labor. |
| IS220PAICH2A | ⚠️ Software compatible | Newer generation with documented 10 AI / 2 AO channels. Requires ToolboxST project update and terminal board verification. Not a blind swap. |
| IS220PAICH2B | ❌ Hardware mod required | Different revision tier. Requires full engineering review and likely project recompilation. |
Frequently Asked Questions (FAQ)
Q: Can I hot-swap an IS220PAICH1A?
A: The pack has a soft-start feature on the power input, which helps with inrush current. But in a live turbine control system, I would never pull a pack without a maintenance window and operator approval — especially in a TMR configuration where pulling one pack degrades redundancy. Do it right, not fast.Q: What’s the difference between IS220PAICH1A and IS220PAICH2A?
A: The H2 revision is newer and has documented specs: 10 analog inputs (8 configurable as 5/10 V or 4–20 mA, 2 as 1/4–20 mA) and 2 current loop outputs. The H1 channel configuration isn’t published as clearly in public sources. Don’t assume they’re pin-compatible. Check your ToolboxST project and terminal board before substituting.Q: Is this still available new from GE?
A: This is a mature product. Some distributors list new or new-old-stock units, but availability varies. Surplus and refurbished units are common in the secondary market. Confirm condition, revision, and warranty terms before ordering.Q: What terminal boards does this work with?
A: IS200STAIH1A, IS200STAIH2A, and IS200TBAIH1C. The terminal board defines the actual analog channel count and signal types. The pack itself is the Ethernet-to-terminal-board interface.Q: What warranty do you offer?
A: 12 months covering defects, spec mismatch, and testing oversights. Damage from wrong supply voltage, ESD, or improper installation is not covered.Q: How do I verify authenticity before installing?
A: Check three things: the full order code (IS220PAICH1A) and revision on the label, the GE Energy / GE Boards & Turbine Control branding, and a successful IONet link with the controller in ToolboxST. If any of those fail, don’t put it in service.
