> ## Documentation Index > Fetch the complete documentation index at: https://docs.wuji.tech/llms.txt > Use this file to discover all available pages before exploring further. # Fault Logs and Error Codes After connecting to Wuji Hand 2 or Wuji Glove, the SDK automatically logs the appearance and clearance of reported fault codes, including the full code, description, and suggested action. The device firmware must support fault-code reporting. Devices without this capability still connect normally. ## Find Fault Records With the SDK's default logger, fault information appears in these locations: | Location | Contents | | - | - | | Terminal | Groups components with the same fault and state, with the description and suggested action | | `~/.wuji/logs/sdk_.log` | Per-component records, connection summaries, and summaries of faults that remain active | | `~/.wuji/logs/error_codes.log` | Per-component fault changes and device history summaries, appended across process restarts and device disconnections | `error_codes.log` is independent of the SDK log level and date-based cleanup. Before a write would exceed 50 MiB, the SDK rotates it to `error_codes.log.1`, keeping the current file and one backup. Back up both files regularly if longer retention is needed. The device reports faults that were active during each second at 1 Hz. The SDK records fault appearances and clearances, then summarizes persistent faults every 10 received frames, about 10 seconds during continuous reception. This summary goes to the terminal and `sdk_.log`, without repeating it in `error_codes.log`. ## Read States and Full Codes | Log Content | Meaning | | - | - | | `state=active` | A received fault wasn't previously recorded as active, including a transient fault that appeared and cleared within the second | | `state=cleared` | A later status confirms the fault has cleared. A transient fault's clearance normally appears one frame later | | `state=active_before_power_off` | A fault Wuji Hand 2 saved as active before power loss. It doesn't establish that the fault is still active on this connection | | `state=history` | A Wuji Glove fault summary from this power-on period. Check its `active` field for the state | | `still active` | A summary of faults still present in the latest status | Repeated appearances and clearances within one second can be combined into one status period. Use the log to locate faults, rather than as a complete timeline of every transition. If the log reports omitted records, include that message and its context when contacting support. A full code has the form `AA-BB-CCCC`. Terminal output may add an `E-` prefix. When several components report the same code, their `BB` values are joined with `/`. | Field | Meaning | | - | - | | `AA` | Two-digit hexadecimal product code. `01` identifies Wuji Hand 2, and `11` identifies Wuji Glove. The current SDK looks up fault codes for these two products | | `BB` | Decimal component ID. The format accepts `0–255`, and logs use at least two digits, such as `06`. The host log records the same ID in `component_id`, while the terminal shows the component name. Use that name to identify the actual component | | `CCCC` | Four-digit hexadecimal native fault code, from `0000` to `FFFF`. `0000` means no fault. Look up nonzero codes in the catalog selected by `AA`. Read severity and clearing behavior from the result's `severity` and `clear_policy` fields | For example, `E-01-06-2102` means component `06` on Wuji Hand 2 reported native code `2102`. The terminal names this component `index_mcp_flex (F1S1)`. `E-01-06/11-2102` means components `06` and `11` reported the same native code. `E-11-32-0102` means component `32` on Wuji Glove reported native code `0102`. The terminal names this component `Index IMU`. Copy the full code into the [error code lookup](#look-up-error-codes) to get its cause and suggested action. The lookup uses `AA` to select the product catalog and `CCCC` to match an entry. `BB` identifies the component without changing the lookup result. Both Python and C provide this lookup without a device connection. ## Look Up Error Codes Look up a full code from the log to get the fault name, cause, and suggested action. No device connection is needed. The code accepts an `E-` prefix and grouped component numbers, such as `E-01-06/11-2102`. **Python** ```python theme={null} import wuji_sdk full_code = "E-01-06-2102" info = wuji_sdk.describe_error(full_code) if info is None: print(f"No catalog entry for {full_code}") else: print(f"code: {full_code}") for field in ("name", "severity", "clear_policy", "resolution"): print(f"{field}: {info[field]}") ``` An invalid format, unknown product, or unlisted fault code returns `None`. `ErrorInfo` is a dictionary. Access fields with `info["name"]`. `desc`, `cause`, and `resolution` contain English text. Chinese text is in `desc_zh`, `cause_zh`, and `resolution_zh`, with an empty string when unavailable. For example, `info["resolution_zh"] or info["resolution"]` prefers the Chinese suggested action. **C** ```c theme={null} #include #include "wuji_sdk.h" int main(void) { const char *full_code = "E-01-06-2102"; WujiErrorInfo info = {0}; WujiStatus status = wuji_describe_error(full_code, &info); if (status != WUJI_STATUS_OK) { const char *message = wuji_last_error(); fprintf(stderr, "%s: %s\n", full_code, message != NULL ? message : "Lookup failed"); return 1; } printf("code: %s\n", full_code); printf("name: %s\n", info.name); printf("severity: %s\n", info.severity); printf("clear_policy: %s\n", info.clear_policy); printf("resolution: %s\n", info.resolution); return 0; } ``` When `wuji_describe_error(const char *full_code, WujiErrorInfo *out)` returns `WUJI_STATUS_OK`, `out` contains the result. An invalid code format or a required `NULL` pointer returns `WUJI_STATUS_ERR_INVALID_ARG`. A valid format with an unknown product or fault code returns `WUJI_STATUS_ERR_NOT_FOUND`. Use `wuji_last_error()` for failure details. `WujiErrorInfo` contains fixed string buffers and needs no release call. `desc`, `cause`, and `resolution` contain English text. The structure has no `_zh` fields. ### Lookup Results | Field | Meaning | | - | - | | `code` | Native integer fault code | | `name` | Fault symbol name | | `severity` | `Warning`, `DeferredStop`, `ImmediateStop`, or `Fatal` for Wuji Hand 2. `Warning` or `Error` for Wuji Glove | | `clear_policy` | `AutoClear`, `ManualClear`, or `NonClearable` | | `desc` / `cause` / `resolution` | Fault description, cause, and suggested action | ### Look Up Integer Fault Codes Use the full-code lookup above for Wuji Glove. Wuji Hand 2 also exposes native `u16` integer codes in fields such as `error_code_current` in `joint_diagnostics`. Query these integers directly with `WujiHand2.describe_error(code)` or `wuji_hand_2_describe_error(code, &info)`. Python returns the same dictionary structure, and C returns the same `WujiErrorInfo`. Native code `0` means no active fault. Python returns `None`, and C returns `WUJI_STATUS_ERR_NOT_FOUND`. Unknown nonzero codes return the same results, so retain the code for fault reports. Encoder calibration values `enc1_error_code` / `enc2_error_code` and the Wuji Hand `u32` error bitfield belong to other categories and must not be passed to these lookup functions. ## Distinguish Device History from Host Logs When Wuji Glove connects, the SDK records a summary of faults from the current power-on period, including faults that occurred while the SDK was disconnected. Power loss clears this device-side history. The computer retains records already written to `error_codes.log`, subject to file-size rotation. For Wuji Hand 2 power-loss records and their limits, see [Diagnostics and Logging](https://docs.wuji.tech/docs/en/wuji-hand/latest/sdk-reference/diagnostics.md#fault-logs). Device fault logs and the [device log export](https://docs.wuji.tech/docs/en/wuji-sdk/latest/advanced.md#device-logging) contain different information. Include both when reporting a fault. This documentation is built and hosted on [Mintlify](https://mintlify.com), a developer documentation platform.