IS220PDOAH1A Discrete Output Pack — New Surplus Factory Package

This IS220PDOAH1A ships new surplus factory package (NSFP): unused stock, still in GE's original packaging. The pack measures roughly 3.25 x 1.65 x 4.78 in (about 8.26 x 4.19 x 12.1 cm), runs on a 28 V dc feed through a 3-pin power connector with soft-start current limiting, and carries a conformal coating over its board for protection in cabinet environments. It is the discrete output pack in the Mark VIe distributed I/O family, mounting directly on a discrete output terminal board via a DC-37 pin connector and reaching the <R>, <S>, or <T> controller over IONet through dual RJ-45 ports.

PDOA drives up to 12 relay outputs and monitors relay and coil feedback — on the order of 15 monitored inputs back from the terminal board. Which relay technology is actually switched depends on the terminal board installed: electromagnetic relays on TRLYH1B, C, D, or F boards, or solid-state relays on TRLYH1E boards. A high-speed processor with RAM and flash memory, a hardware watchdog and reset circuit, and status-indication LEDs round out the pack's diagnostics, alongside a local infrared port for serial communications.

Confirm the Fault Before You Install a Replacement

• Field wiring and the relay hardware itself live on the terminal board — a stuck contact, blown fuse, or loose terminal there produces the same symptom as a bad output on the pack.
• Use the swap test: install the suspect pack on a known-good terminal board, or a known-good pack on the suspect board, and see which one the fault follows before committing to a new part.
• Remember that all outputs are held disabled during the pack's power-up self-test — that's expected behavior immediately after a power cycle, not a fault.
• Confirm the terminal board's relay type matches the application; solid-state (TRLYH1E) and electromagnetic (TRLYH1B/C/D/F) boards are not interchangeable, and a mismatch can look like a pack problem.
• Rule out the IONet path — cabling, connectors, and switch health — before condemning the pack itself.

What the Part Number Tells You

IS220 marks a Mark VIe distributed I/O pack, PDOA the discrete output function, H1 the design generation, and the trailing A the hardware/processor revision. Suffix and revision both need to match your terminal board and ControlST project. Our GE Speedtronic Part Number Decoder explains the full naming convention.

Related Packs and Boards

PDOA pairs with TRLY-family relay terminal boards. Where a system combines discrete input and output on one terminal board, the related PDIO pack does both jobs from a single assembly. See our GE Mark VI IS200 Boards collection for compatible terminal boards.

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