> For the complete documentation index, see [llms.txt](https://docs.didge.io/home/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.didge.io/home/foodcore-sensors/admin/calibration/master-calibration.md). # Master Calibration #### Step 1: Prepare Master Sensors Before any calibration begins, a set of pre-validated sensors, referred to as masters, must be set up. These are the baseline for all future calibrations. * Add sensors to the system: Master sensors must already exist in Didge as active devices. * Create a dedicated dashboard (e.g., “Master Sensors”) and group these devices (e.g., 20 master sensors). * Device requirements: Use Dragino sensors (or equivalent) with both probe and ambient capabilities. * Reference thermometer (recommended): Use a certified NATA (National Association of Testing Authorities) thermometer as a reference check during boiling and freezing calibration.
*** #### Step 2: Equipment and Setup * Access to crushed ice + water (for 0.0 °C reference) and boiling water (100.0 °C reference). * Set the sensor transmit rate to every 1 minute using a bulk downlink command. This ensures timely updates for calibration. * Wait \~40 minutes for sensors to reflect the new send rate in TTS.
*** #### Freezing Point Calibration 1. Submerge the probe tip into an ice-water mix. 2. Navigate to the master device dashboard in the calibration section. 3. Choose: * Manual Method: Freezing * Tolerance (Probe): ±0.5 °C * Tolerance (Ambient): Disabled * Success Threshold: 5 (i.e., 5 consecutive valid readings) 4. Click Start Calibration. 5. The system checks if the sensor stays within ±0.5 °C of 0.0 °C for 5 consecutive readings. 6. Upon success, the session closes and is marked as calibrated.
*** #### Boiling Point Calibration Repeat the above steps, but with boiling water: * Select Manual Method: Boiling * Use the same tolerance and threshold values. * Submerge the tip of the probe in vigorously boiling water. * The system checks if the sensor stays within ±0.5 °C of 100.0 °C for 5 consecutive readings. > ⚠️ Use proper precautions to avoid burns or cable damage during boiling tests.
*** #### Why 0.5 °C Tolerance for Masters? The ±0.5 °C threshold is deliberately strict. This tighter calibration tolerance is used to account for uncertainties inherent in reference methods (e.g., slight thermal inconsistencies in ice baths or boiling water altitude variations). Since these sensors will serve as reference standards, higher rigor ensures reliability. *** #### Calibrating Target Devices Against Masters Once master units are certified: * Use them to calibrate target devices in the field or production environments. * In this stage, use a broader tolerance of ±1.0 °C, which aligns with: * Australian food compliance standards * FDA and international food safety benchmarks
The calibration module allows flexible tolerance settings, but these are the recommended levels for regulatory compliance and operational consistency.
*** #### Recordkeeping & Certification * Each completed calibration event is stored in the system. * It’s strongly advised to retain the records for each master sensor’s calibration to establish traceability. * Master units must be recalibrated regularly (interval based on your compliance program). --- # Agent Instructions This documentation is published with GitBook. GitBook is the documentation platform designed so that both humans and AI agents can read, navigate, and reason over technical content effectively. Learn more at gitbook.com. ## Querying This Documentation If you need additional information that is not directly available in this page, you can query the documentation by asking a question. Perform an HTTP GET request on the following URL with the `ask` and `goal` query parameters: ``` GET https://docs.didge.io/home/foodcore-sensors/admin/calibration/master-calibration.md?ask=&goal= ``` `ask` is the immediate question: it should be specific, self-contained, and written in natural language. `goal` is what the user is ultimately trying to achieve, the reason they need the answer. Sharing it helps GitBook give you a better, more relevant answer. A goal is most helpful when it describes the outcome the user wants rather than restating the question. For example, with `ask=how do I create an API token`, a goal like `automate deployments from our CI pipeline` lets GitBook tailor the answer to that use case. The response will contain a direct answer to the question and relevant excerpts and sources from the documentation. Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.