IS220PAICH1A REV. D — Mark VIe Analog I/O Pack

Board revisions on GE's Speedtronic I/O packs climb steadily over a long production run, and REV. D simply marks where this particular IS220PAICH1A sits in that history. Functionally, it is still the same PAIC pack: the analog I/O interface between the Mark VIe (or Mark VIeS) controller and an analog input terminal board. The pack does not process signals in isolation — it plugs directly onto the terminal board via a single DC-37 pin connector and exchanges data with the <R>, <S>, or <T> controller over the I/O Ethernet network (IONet) through dual RJ-45 ports.

Every PAIC pack combines a processor board common to all Mark VIe distributed I/O packs with an acquisition board built specifically for analog work: 10 analog inputs (the first eight switchable between 5 V, 10 V, or 4-20 mA current loop; the last two between ±1 mA or 4-20 mA) and 2 analog outputs at 0-20 mA on this H1 generation. A 16-bit A/D converter handles the input side, a 14-bit D/A converter handles the outputs, and the pack runs a normal scan of 5 ms (200 Hz). The load resistors for the current-loop inputs sit on the terminal board itself, not inside the pack.

Diagnose Before You Swap the Pack

The IS220PAIC is one part of a chain: field device, wiring, terminal board, pack, IONet, controller. A bad analog value can originate anywhere in that chain, and replacing the pack is only the right call if the pack is actually where the fault sits.

• Start with the terminal board, not the pack. Load resistors, field terminals, and wiring all live on the board. An open or drifted resistor produces the same symptom as a bad input channel on the PAIC.
• Use the swap test: put the suspect pack on a known-good terminal board, or a known-good pack on the suspect board. Whichever the fault follows is the part that needs replacing — this is standard practice on Mark VIe I/O packs and prevents ordering the wrong part.
• Rule out the network before the hardware: confirm both ENET1 and ENET2 links are active, check connectors for corrosion, and confirm the IONet switch is healthy. A network dropout can look identical to a dead pack from the operator station.
• Check the terminal board revision. GE's own documentation notes that running a PAIC on an unsupported or older terminal board revision throws a compatibility alarm — that is a mismatch, not a failure, and no part needs to be replaced to clear it.
• A genuine pack fault does exist: a suicide-relay or output alarm tied to an analog output points at the acquisition board inside the pack itself, and that is a case where pack replacement is the correct fix.

What REV. D and the Rest of the Part Number Tell You

Reading left to right: IS220 marks a Mark VIe distributed I/O pack, PAIC is the analog I/O function, H1 is the base output generation (two 0-20 mA outputs; H2 adds a 0-200 mA option on output 1), the trailing letter is a processor/hardware revision, and REV. D is the board revision within that part number. When you're sourcing a replacement, match all of it — not just the PAIC prefix — against your terminal board and ControlST project. Our GE Speedtronic Part Number Decoder walks through the full naming convention if you need to confirm what you're looking at.

Related Hardware

PAIC packs mount on TBAI/STAI-family analog terminal boards (not the DIN-rail DTAI board). For discrete signals on the same panel, the equivalent packs are PDIA (contact input) and PDOA (discrete output), or PDIO where input and output are combined on one pack. Our GE Mark VI IS200 Boards collection covers the terminal boards these packs pair with.

Ready to Order? Here's What Speeds Up Your Quote

• The full part number as printed, including suffix and REV letter
• A photo of the label if you have one handy
• Turbine model and control generation (Mark VI, VIe, VIeS)
• Quantity
• How urgent the need is — scheduled outage or unplanned event

We respond to every quote request within 24 hours. AloTechParts ships worldwide, DDP, and works with purchase orders — this is a request-a-quote store, so nothing is charged automatically and there is always a person confirming the order before it ships.

General Information about the Product
Part Number	IS220PAICH1A Mark VI IS220
Description	GE General Electric IS220PAICH1A REV. D Power Distribution Pack Mark VI
Condition	used Clean and Tested. With 1 Year Warranty.