Appendix

This page collects term definitions, error code carriers, and version requirements. The full explanations stay in the capability chapters.

Glossary

Term	Description
Resource	The uniform representation of a device capability in the SDK, reached through semantic methods. A resource is either a readable or writable parameter or a subscribable topic. To list them, see SDK Users and Calibration Data — Listing All Resources
Topic	The identifier of a subscribable data stream. One topic carries one sensor output or computed result
Subscription	The handle that receives data from a topic, with async, sync non-blocking, and callback delivery. See Data Subscription Mechanism — Subscription Modes
Global resource	A resource that merges data from every connected device, subscribed through the `SdkManager`-level API. See Data Subscription Mechanism — Cross-device Merged Subscription
Derived stream	A stream computed from a device source stream, such as `hand_joint_angles`, `hand_skeleton`, `tip_poses`, and `imu_data_<finger>`. A derived stream follows the rate of its source stream and can’t be adjusted on its own
Output rate	The frequency at which the firmware pushes a stream. To change it, see Data Subscription Mechanism — Adjusting the Stream Output Rate
MCAP	The recording file format. Multiple sensor streams are written to one file in sync. See Data Recording and Offline Processing
Episode	A self-contained segment of a recording session. Switching writes a new file and reuses the registered channels. See Data Recording and Offline Processing — Episode Switching
SDK user	The isolation unit for local parameters and calibration files, keyed by operator. See SDK Users and Calibration Data — SDK User Management
Hand model calibration	The process that builds a hand model for the current SDK user and hand side. Artifacts are stored per user. See SDK Users and Calibration Data — Calibration
Hand retargeting	The computation that maps 21 MediaPipe-format hand keypoints to a 20-dimensional joint angle command. See Hand Retargeting
Handedness	The left or right hand marker on a frame or device. For the field definition, see Common Data Types — Handedness
FrameHeader	The header shared by data frames, carrying `frame_id` and the 64-bit microsecond timestamp `timestamp_us`. See Common Data Types — FrameHeader
Sync offset (`offset_us`)	The difference between the device clock and the host UTC clock computed by one synchronization, in microseconds
Round trip (`round_trip_us`)	The round-trip time of one synchronization. A smaller value means better sync quality. See Time Synchronization and Coordinate Transforms — Sync accuracy
Typed callback	The strongly typed subscription callback the C API provides per device type. The frame pointer is valid only during the callback. See C API Reference — Usage constraints

Error Code Index

SDK errors arrive through five carriers. The three device-side code families are unrelated, so a value from one means nothing in another.

Carrier	Shape	Where it comes from	How to decode
Python exception	`WujiException` and more specific subclasses	Most Python API calls	Catch it and branch on the error name. For common types, see Python Exception Types on this page
C return code	The `WujiStatus` enum	Most C API calls	`WUJI_STATUS_OK` means success. On failure, read the current thread’s description with `wuji_last_error()`. See C API Reference — Initialization and conventions
Device fault code	`u16`	Wuji Hand 2 joint diagnostics, error status, error history, and encoder calibration results	Decode with `WujiHand2.describe_error()` or `wuji_hand_2_describe_error()`. See Common Data Types — Error Code Categories
Encoder calibration code	`u8`	`enc1_error_code` and `enc2_error_code` in encoder calibration results	A calibration-only enum. Read `enc1_error_name` and `enc2_error_name` from the result object, and don’t pass the value to the decode function. See Common Data Types — Error Code Categories
Wuji Hand error bitfield	`u32`	`error_code` in Wuji Hand joint diagnostics	One bit per fault condition. Check it bit by bit, and don’t pass the value to the decode function. See Common Data Types — Error Code Categories

Code 0 means no active fault and isn’t in the catalog. When a nonzero code won’t decode, keep the raw value for logs and bug reports.

Python Exception Types

Most Python API calls raise WujiException on failure, and the message carries an error type prefix. Some APIs raise more specific exceptions for file system or validation errors. Check the API reference for details.

Error	Description
`DeviceNotFound`	Specified device not found
`DeviceMismatch`	Device type mismatch
`Disconnected`	Device has been disconnected
`ConnectionTimeout`	Connection timed out
`OperationTimeout`	Operation timed out
`PathNotFound`	Resource path does not exist
`SchemaMismatch`	Data type mismatch
`NoData`	No data available
`StreamClosed`	Subscription stream has been closed

For catch-and-branch examples, see Best Practices — Error Handling. For reconnecting after a drop, see Best Practices — Reconnection Strategy.

Version Compatibility

For runtime requirements, see Installation and Environment — System Requirements. Hand retargeting ships prebuilt packages for Linux x86_64 and Linux aarch64 only. See Hand Retargeting — Platform and limits. The capabilities below set a minimum firmware or SDK version. Everything not listed here works with the installed SDK version.

Capability	Minimum firmware	Minimum SDK	Details
Fingertip tactile data	Wuji Hand 2 v2.1.0	v2026.7.21	Fingertip Tactile — Requirements
Fingertip tactile stream rate control	Wuji Hand 2 v2.3.0	v2026.8.17	Fingertip Tactile — Requirements
Normalized per-point force format	Wuji Hand 2 v2.4.0	v2026.8.17	Fingertip Tactile — Self-Describing Data Format
Contact point placement on the hand model	Wuji Hand 2 v2.5.0	Follows firmware	Fingertip Tactile — Place Points on the Hand Model
Application point of the resultant force	Wuji Hand 2 v2.6.0	Follows firmware	Fingertip Tactile — Place Points on the Hand Model
`NodeOfflineError` when calibration hits an offline finger	Wuji Hand 2 v2.6.0	v2026.8.31	Fingertip Tactile — Zero-Baseline Calibration and Status
Flash log export	No extra requirement	v2026.8.31	Troubleshooting — Device Log Export
Concurrent Flash log export on one device	Wuji Hand 2 v2.6.0	v2026.8.31	Wuji Hand 2 Diagnostics and Logs — Flash Log Export

For the full change history, see the Changelog.

Overview

Hardware

Software

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Glossary

Error Code Index

Python Exception Types

Version Compatibility

​Glossary

​Error Code Index

​Python Exception Types

​Version Compatibility

Glossary

Error Code Index

Python Exception Types

Version Compatibility