Key Technical Specifications
| Parameter | Value |
|---|---|
| Module type | Discrete Input I/O Pack (PDIA) |
| System family | GE Mark VIe Speedtronic |
| Part number | 336A4940CSP1 |
| Discrete inputs | Up to 24 channels (terminal-board dependent) |
| Contact wetting voltage | 32 VDC typical |
| Supply voltage | 27.4 VDC nominal (28 VDC typical) |
| Communication | Dual RJ-45 IONet (Ethernet) |
| Configuration tool | ToolboxST |
| LEDs | Power, ENet1, ENet2, ASTN, relay/channel indicators |
| Operating temperature | -30°C to +65°C |
| Hazardous area | Class I, Div 2; ATEX Zone 2 (with approved terminal board) |
| Mounting | Terminal-board mounted (DIN-rail terminal board) |
Product Introduction
If you have ever chased a “missing trip signal” on a Mark VIe rack, you know the problem is rarely the controller. It is usually the I/O Pack sitting between the controller and the terminal board. The IS220PDIAH1A is GE’s discrete input Pack for the Mark VIe Speedtronic system. It takes dual IONet Ethernet traffic and translates it into discrete status inputs from field devices such as pressure switches, limit switches, and relay contacts.Field crews keep this Pack because it is simple, isolated, and configurable through ToolboxST. It supports up to 24 discrete inputs depending on the terminal board, runs on a 27.4–28 VDC supply, and carries hazardous-area approvals when paired with the correct IS200/IS400 terminal board. The revision suffix matters here. An “H1A” is not automatically interchangeable with an “H1B” without checking the firmware and terminal-board compatibility.
Quality SOP & Tech Pitfalls
The Lab Report (SOP):
- Visual inspection: verify IS220PDIAH1A label, 336A4940CSP1 assembly number, revision, and connector pin condition.
- Photograph existing IONet cabling, terminal board type, and LED state before removal.
- Live test on a Mark VIe test bench with 27.4–28 VDC supply and dual Ethernet.
- Verify ENet1/ENet2 link LEDs, power LED, and ASTN status.
- Simulate discrete inputs at the terminal board and confirm channel recognition in ToolboxST.
- Record firmware revision, log test results, and pack in anti-static shielding.
The Engineer’s Warning (Pitfalls):
- The most common mistake is swapping the terminal board type. PDIA Packs work with specific discrete input boards such as IS200STCIH1A, IS200STCIH2A, IS200STCIH8A, IS200TBCIH2C, and IS200TBCIH4C. Put it on the wrong board and the channel map will not match.
- Another failure I see repeatedly: crews replace the Pack but forget to verify the IONet node address and firmware. The Pack may link up but report faults or refuse to download configuration.
- Do not assume 24 VDC field power is present at the terminal board. The contact wetting voltage is typically 32 VDC, and the source comes from the terminal board, not the Pack itself.
Installation & Configuration Guide
Pre-Installation: ⚠️ De-energize the I/O Pack supply if the system does not support live replacement. Photograph IONet port assignments, terminal board model, and LED indicators. Confirm the terminal board part number matches the existing configuration.Removal: Disconnect IONet cables first. Remove the mechanical retaining hardware near the Ethernet ports. Pull the Pack straight off the terminal board connector. Do not rock it side to side.Installation: Verify the replacement is IS220PDIAH1A with matching revision. Seat it firmly onto the terminal board DC connector. Reinstall the retaining hardware so no strain is placed on the connector. Reconnect ENet1 and ENet2 exactly as labeled.Power-On & Testing: Apply 27.4–28 VDC. Confirm power LED and Ethernet link LEDs. Use ToolboxST to verify the Pack is recognized, firmware matches, and all discrete inputs report correctly. Force test each channel if permitted by the safety procedure.
Compatible Replacement Models
- ✅ IS220PDIAH1A (same revision): Direct drop-in when terminal board and firmware match. Confirm 336A4940CSP1 or equivalent assembly number.
- ⚠️ IS220PDIAH1B: Same PDIA family but may differ in firmware, input mapping, or wetting current. Requires ToolboxST verification and possibly a firmware update. Allow 30–60 minutes for validation.
- ⚠️ IS220PDIOH1A: Combines discrete input and discrete output functions. Not a direct substitute unless the application was originally designed for PDIO and the terminal board supports it.
- ❌ IS220PAICH1A / IS220PDOAH1A: Analog Pack and discrete output Pack. Not compatible with a discrete input application.
Frequently Asked Questions (FAQ)
Is IS220PDIAH1A the same as IS220PDIAH1B?
No. They belong to the same PDIA family, but revision differences can affect firmware, input handling, and terminal-board compatibility. Always verify before substitution.How many inputs does it support?
Up to 24 discrete inputs, depending on the terminal board. Some boards may support fewer channels.What voltage does it need?
The Pack supply is nominally 27.4 VDC, typically referenced as 28 VDC. Contact wetting voltage is typically 32 VDC and comes from the terminal board.Can I hot-swap it?
Mark VIe Packs include soft-start and are often replaceable without removing system power, but only do this if your site procedure and safety case allow it. Pulling the wrong Pack on a live turbine rack can cause nuisance trips.Which terminal boards work with it?
Common pairings include IS200STCIH1A, IS200STCIH2A, IS200STCIH8A, IS200TBCIH2C, and IS200TBCIH4C. Confirm against the GE installation manual for your exact revision.Does it need ToolboxST?
Yes. Configuration, diagnostics, and firmware checks are handled through ToolboxST. You cannot properly commission it without access to the control software.Is it approved for hazardous areas?
Yes, when installed with the correct terminal board and per GE documentation. Typical approvals include Class I, Div 2 and ATEX Zone 2.
