What the IS215UCVEH2A Controls in a Mark VI Rack

When a Mark VI panel throws a controller diagnostic, the IS215UCVEH2A is the board most operators suspect first — the QNX-based main processor that executes the turbine control blocks. It is the standard controller of the GE Speedtronic Mark VI system, and this listing covers a tested, used UCVEH2A at the H2AE revision.

Processor, Memory and the UDH Link

The UCVE carries the entire turbine application on one VME card. It runs on a 300 MHz Intel Celeron under QNX with 32 MB of DRAM (specifications that match across independent supplier inspections), holds its control signal database on board, and connects to the Unit Data Highway through a single 10BaseT/100BaseTX RJ-45 Ethernet port. Programming is Boolean, and the operating range spans roughly −30 to 65 °C. Data to and from the I/O moves across the VME backplane by way of the VCMI communication board, to which the controller synchronizes its clock.

Before You Blame the Controller: A Field Checklist

Replacing a UCVE is a meaningful outage and expense, so make sure the controller is the actual fault. In the field, most controller-is-dead calls resolve to one of these:

• A configuration or firmware mismatch. The board checks its toolbox configuration against the hardware every power-up; a wrong or partial ControlST download, or corrupt boot media, will fault a healthy controller. Reload first.
• A VCMI or IONet problem. Because the controller only sees the I/O through the VCMI over the VME backplane, a VCMI failure or an IONet fault can mimic a controller failure. Inspect the VCMI and the backplane seating.
• Rack power. The UCVE pulls several amps on the +5 V rail; a weak or drooping supply will reset it repeatedly.
• A downstream I/O fault. A single failing I/O board or pack can generate diagnostics that look like they come from the controller.
• In TMR, the wrong core. With one of <R>, <S> or <T> down and the machine still voting, confirm which core is affected and whether its UCVE, rack, VCMI or power is to blame before ordering.

Working the list in order turns a guess into a diagnosis.

How to Read the Suffix and Generation

The part number is built in blocks: IS215 (Mark VI special assembly), UCVE (controller type and generation), H2A (hardware variant) and a revision letter — here the "E" of H2AE. Note that the H-series UCVEH2 is the base controller with a single Ethernet port; the M-series adds Ethernet ports and Profibus, so an H-series and an M-series are not casual substitutes. And because UCVE is only one of the UCVx generations (alongside UCVB, UCVD and UCVG), the generation letter must match too. Our GE Speedtronic Part Number Decoder details each field.

Companion Boards and Collections

The VCMI communication board is the UCVE's constant partner in the VME rack. To see where the Mark VI controller fits in GE's lineage, read Mark V vs Mark VI: DS200 to IS200, and find related cards in the GE Mark VI IS200 Boards and GE Speedtronic Turbine Control Boards collections.

Ordering the Correct IS215UCVEH2A

Send us the complete part number and suffix (IS215UCVEH2A / H2AE), the revision, a photo of the board label, the turbine model and Mark VI generation, simplex or TMR architecture, the ControlST or firmware version if you can read it, the quantity, and your timeline. The controlling manual for Mark VI controllers is GEH-6421.

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