Description
ZYGO ZMI-2002 8020-0211 | Dual-Axis VME Measurement Board | Precision Interferometry
Key Technical Specifications
| Parameter | Specification |
|---|---|
| Manufacturer | ZYGO Corporation |
| Model | |
| Part Number | 8020-0211 |
| Product Type | Dual-Axis VME Measurement Board |
| Product Family | ZMI 2000 |
| Number of Axes | 2 |
| Form Factor | 6U VME |
| VME Specification | VMEbus Revision C.1 |
| Addressing | A16 / A24 |
| Data Transfer | D16 / D32 |
| Position Data | 36-bit, two’s complement |
| Velocity Data | 32-bit, two’s complement |
| Time Range | 107.4 seconds |
| Time Format | 32-bit, two’s complement |
| Time Resolution | 25 ns |
| Main Supply | +5 V ±5%, approximately 3.5 A |
| P2 Interface | Simplified P2 interface |
| P2 Data Rate | Up to 7.7 MHz |
| Optical Signal | Reference and measurement signals |
| System Synchronization | Clock input or clock output |
| Axis Capacity | Two axes per board |
| Multi-Axis Expansion | Up to 16 axes through the ZMI 2000 P2 architecture |
The ZMI 2000 architecture supports single- and dual-axis measurement boards, with the providing two interferometric axes on one 6U VME board. The simplified P2 interface allows multiple boards to share measurement data with a servo card or motion controller, with the published architecture supporting up to 16 axes at the stated P2 data rate.
Product Introduction
The ZYGO 8020-0211 is a dual-axis measurement board designed for ZYGO interferometric measurement systems. Rather than functioning as a conventional PLC, motion controller, or general-purpose analog acquisition card, it acts as a precision measurement processor inside a VME-based system. The board receives reference and measurement signals from the interferometer system and provides digitally processed position, velocity, timing, and diagnostic information to the host control architecture.
The places two measurement axes on a single 6U VME board, which is useful in precision motion systems where measurement feedback has to be synchronized closely with the machine controller. Its 36-bit position representation, 32-bit velocity representation, and 25 ns time resolution are particularly relevant to high-resolution stage positioning, calibration, metrology, and equipment-level motion feedback.
ZMI-2002
Application Scenarios & Field Pitfalls — The Engineer’s Perspective
Engineering Pain Point
When a precision stage begins showing position instability, drift, intermittent feedback, or synchronization errors, replacing the measurement board is not necessarily the correct first step. The optical path, interferometer head, reference signal, measurement signal, fiber connections, timing reference, VME backplane, and host motion-control software all participate in the measurement chain. A should therefore be diagnosed as part of the complete metrology system rather than as an isolated VME card.
Typical Applications
Precision motion stages
The dual-axis architecture is suited to equipment requiring simultaneous position feedback on two mechanical axes.
Semiconductor manufacturing equipment
Interferometric measurement technology is applicable to precision positioning and metrology tasks where conventional encoder feedback may not provide the required measurement characteristics.
Optical and dimensional metrology
The board can form part of a ZYGO measurement system used for high-resolution displacement and geometric measurement.
Precision machine calibration
The ZMI 2000 architecture can provide measurement feedback for calibration and verification of high-accuracy mechanical systems.
Technical Pitfalls
- Do not classify the as a generic PLC or motion CPU.
Its primary role is interferometric measurement processing. The host controller remains responsible for the broader machine-control function. - Verify the complete part-number suffix.
Public references commonly show 8020-0211-1-J in addition to the base 8020-0211 designation. Do not assume that every suffix represents an interchangeable hardware revision. Match the installed board label and equipment documentation. - Check the optical signal path before condemning the PCB.
The board depends on reference and measurement signals. Missing, weak, intermittent, or improperly connected optical signals can appear as electronic measurement faults. - VME compatibility is only the first check.
A mechanically compatible 6U VME card is not automatically a functional substitute. VME addressing, P2 wiring, software drivers, board configuration, timing, and the connected servo/motion controller must all be considered. - Do not confuse measurement resolution with absolute system accuracy.
The 36-bit position format and fine timing resolution describe the electronic data representation and timing capability. Overall measurement accuracy also depends on the interferometer optics, laser source, environmental conditions, alignment, and system calibration. - Check the P2 architecture in multi-axis installations.
The simplified P2 interface is specifically intended to allow multiple measurement boards to communicate with a servo card or motor controller. Incorrect P2 termination or wiring can affect an otherwise healthy board. - Verify the VME power rail.
Published ZMI 2000 information specifies approximately +5 V ±5% at 3.5 A for the ZMI-2001/ family. Before replacing the board, confirm that the VME rack supply remains within specification under load.
Related Products
- ZYGO ZMI-2001 — Single-axis ZMI 2000 VME measurement board; useful where only one interferometric axis is required.
- ZYGO ZMI-PC — ZMI measurement-board variant associated with PC/ISA architectures.
- ZYGO ZMI 2000 Series — Measurement-board family supporting single- and dual-axis configurations.
- ZYGO 8020-0211-1-J — Extended part-number designation associated with the ; verify hardware revision before substitution.
- ZYGO ZMI 7702 — Related ZYGO interferometer/laser-system hardware reported in ZMI system configurations; verify exact system compatibility.
- ZYGO ZMI measurement electronics — Related electronic hardware used for interferometric reference and measurement processing.
- ZYGO ZMI optical measurement components — Reference and measurement signal hardware forming the optical portion of the measurement chain.
Procurement Note
For a ZYGO 8020-0211 replacement, provide the complete PCB marking, including any suffix such as -1-J, along with the VME chassis information, host motion controller/servo card, ZMI system configuration, and photographs of the front and rear connectors.
For used or surplus inventory, inspect the VME edge connector, P2 connector, optical interfaces, PCB contamination, component discoloration, and signs of previous repair. A useful acceptance test should verify VME communication, board initialization, reference/measurement signal detection, timing synchronization, position data, velocity data, and P2 communication with the associated motion-control hardware.
Important: public sources contain unrelated descriptions of this same model number, including servo-drive and PLC classifications. Those descriptions conflict with the much more consistent ZYGO ZMI 2000 documentation. The defensible engineering classification for 8020-0211 is therefore ZYGO dual-axis 6U VME measurement board.
