What data for this category looks like
This category of data comes from flow, pressure, temperature, and analytical instrument manufacturers as well as metrology laboratories. Daily documents include assembly and commissioning sheets, calibration procedures, original calibration records, error curves, metrology certificates, and software version records. Data sources cover design documents, standard instrument monitoring data, calibration software outputs, laboratory information systems, and customer range requirements. The update frequency is once per calibration for each device. Documents include clear fields and corresponding physical units such as range, error value, calibration date, and traceability number.
What constraints these characteristics impose on vector models and indexes
This category of data has a high update frequency, and each single data entry is associated with the full calibration process of one device. The indexing link must support incremental updates to avoid time-consuming full reconstruction. Documents include structured forms, curve data descriptions, and professional technical texts. The vector model must support feature extraction for multiple content types. Fields include key identifiers such as traceability numbers and error values. When splitting text chunks, field associations must be retained to ensure retrieval accuracy. Calibration results are directly linked to customer production. The accuracy of retrieval recall must meet metrology audit requirements, and the matching precision of recall results must be strictly controlled.
How to set configurations
| Configuration Item | Recommended Range | Rationale |
|---|---|---|
| Chunk Length | 800–1200 characters | Adapts to natural segmentation of documents such as calibration procedures and error curve descriptions, avoids breaking associations between key fields such as traceability numbers |
| Overlap Length | 100–200 characters | Retains field associations between adjacent chunks, prevents cross-chunk calibration record information from being broken |
| Similarity Threshold | 0.75–0.85 | Matches professional text features of calibration records and metrology certificates, filters low-correlation results to meet metrology audit requirements |
| Single Search Limit | Top 8 entries | Balances retrieval efficiency and recall completeness, adapts to the volume of calibration data for a single device |
| maxToken | Set to the selected embedding model/service maximum supported input tokens | maxToken is the input-token maximum supported by the selected embedding model/service; verify it in that provider configuration. See the v4.17.2 model-field reference. It is not retrieval/LLM context or a FastGPT-wide fixed cap. |
| defaultToken | Set from representative sample documents | defaultToken is the default token count for direct text chunking; tune it on representative source documents. See the v4.17.2 model-field reference. It is not a vector dimension, embedding-model input cap, or retrieval/LLM context. |
Three common misconfigurations
- Phenomenon: Multiple knowledge bases are called during retrieval, the index of the specified knowledge base cannot be prioritized, and results include irrelevant general equipment documents. Cause: The knowledge base and corresponding index rules are not bound in the vector model configuration, and the knowledge base priority switch is not enabled.
- Phenomenon: A 60-second timeout error is returned during retrieval, and the interface shows task interruption. Cause: Incremental index updates are not configured, full reconstruction of calibration record indexes takes too long, exceeding the system default timeout limit.
- Phenomenon: A batch index addition request for a collection returns a parameter error, and no valid index is generated. Cause: Associated fields such as collection ID, chunk data, and instrument traceability number are not carried according to interface requirements, and the exclusive field format of this category of data is not matched.
How to confirm the configuration is correct
- Navigate to the vector model configuration page, check whether the knowledge base priority switch is enabled, and confirm that the index rules of the specified knowledge base have been bound.
- Initiate a retrieval test for calibration records of a single instrument, review the response time of returned results, and ensure there is no 60-second interruption prompt.
- Submit a batch index addition test request, check whether the returned result contains a valid index ID, and ensure there is no parameter error prompt.
- Retrieve content related to exception reports, confirm that returned results only include documents from the target knowledge base, and there is no irrelevant content across knowledge bases.
The values provided are common starting points and should be measured against the reader's own samples.