IS220PSVOH1A: the Mark VIe servo output I/O pack, not the terminal board

The IS220PSVOH1A is a servo output (PSVO) I/O pack from the GE Speedtronic Mark VIe distributed control platform. Despite listings that label it a servo terminal board, the PSVO is the intelligent I/O pack that plugs onto the separate TSVO servo terminal board, and the two are different parts that work together. The pack provides the electrical interface between one or two IONet Ethernet networks and the TSVO board, and through its onboard WSVO servo driver it manages up to two servo valve position loops. You will find it in gas- and steam-turbine Speedtronic systems, mounted at the I/O level and driving the hydraulic servo valves that position control and fuel actuators.

The faceplate carries paired LED indications: power (PWR) and attention (ATTN), plus link and status for ENet1 and ENet2 and the ENA1/ENA2 enables. An infrared port sits on the front but is not used on this pack. Inside, a processor board with local power supply, flash, RAM and an internal temperature sensor connects to the servo acquisition board. Configuration and diagnostics are handled in ToolboxST: the pack can be auto-reconfigured on replacement, a setting you toggle in the Component Editor, but when the TSVO terminal board itself is swapped the I/O pack must be reconfigured manually.

Confirm the fault is the pack before you order

A servo valve that will not stroke, hunts, or drifts off demand looks like a dead PSVO, but on Mark VIe the pack is often the last thing actually at fault. Before you condemn an IS220PSVOH1A, work through the cheaper and more common causes:

• The servo valve and its coils — an open or shorted coil, oil contamination, stiction, or a shifted null will stop the actuator moving even with a perfectly good pack.
• Field wiring and the LVDT/LVDR position feedback — a broken feedback wire, moisture in a connector, or a loose terminal makes the position loop look unstable; the loop cannot close without healthy feedback.
• The TSVO terminal board — the board, its connector, or its relays can fail while the pack itself is fine.
• IONet cabling — a bad Ethernet cable or port can show the pack offline in ToolboxST even though the hardware is healthy.
• The power feed — check the PWR LED and the pack supply before assuming an internal failure.

Start at the faceplate LEDs and the ToolboxST alarm list, then check LVDT feedback health and the servo current command against the actual. ToolboxST also lets you exercise the loop with the machine offline — stroking the actuator in manual mode, ramping position, or applying a step current while the trend recorder shows any irregularity in the stroke — which separates a valve or feedback problem from a pack problem far faster than swapping hardware. A fault that appears the same way regardless of which pack drives the valve is pointing at the valve, wiring, or terminal board, not the PSVO.

Reading the IS220PSVOH1A part number and H1A suffix

In this number, IS220 identifies the Mark VIe distributed I/O pack platform, PSVO is the servo output function, and the trailing H1A is the hardware revision and variant. Servo packs also exist as IS220PSVOH1B; treat the suffix as something to match rather than guess, because the revision has to line up with your installed hardware and your ControlST/ToolboxST version. If you are decoding a full nameplate string, our GE Speedtronic Part Number Decoder walks through each field.

Related Mark VIe servo and control hardware

The PSVO shares the IONet-and-ToolboxST architecture used across the IS220 pack family, so a control-cabinet refresh often means sourcing analog, discrete, and protection packs alongside it. Browse the GE Mark VI IS200 Boards and the wider GE Speedtronic Turbine Control Boards collections. If your site is stepping up from an older generation, the Mark V vs Mark VI: DS200 to IS200 guide explains how servo and I/O responsibilities shifted between platforms.

What to send with your IS220PSVOH1A quote request

To get the right pack the first time, include:

• The full part number with suffix (IS220PSVOH1A) and the board revision printed on the label.
• A clear photo of the pack label.
• Your turbine model and Mark VIe or Mark VI generation.
• Quantity needed and how urgent the requirement is.

This unit is offered used, cleaned and tested, with a 1-year warranty as shown below.

Request a quote for the IS220PSVOH1A

Tell us what you need and we will send a quote within 24 hours. We ship worldwide on DDP terms and accept purchase orders from qualified organizations. Use the Request a Quote button to start, and include the details above so we can confirm the exact revision for your system.