Target Calibration

Overview

This documentation outlines the process for conducting a calibration on temperature sensors within the MFC wireless monitoring system. Calibration ensures that sensor readings are accurate and aligned with verified master units. This is critical to maintaining reliable environmental monitoring in controlled storage environments.

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Prerequisites

Before initiating the calibration process:

• Master Unit: Must have a pre-calibrated and verified accurate temperature sensor.

• Send Rate Configuration: Both the master and target units must be configured to transmit data at 1-minute intervals.

  • This must be verified by confirming 1-minute spaced data records from both units.

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Key Terms

• Master Device: A pre-calibrated unit that serves as the reference.

• Target Device: The unit being calibrated.

• Tolerance: The acceptable variance (e.g., ± 1°C) between master and target readings.

• Success Threshold: Number of consecutive in-range readings required to pass (typically 5).

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Calibration Procedure

1. Initiate Calibration:

   • Select the target sensor within the system dashboard.

   • Click on the "Calibrate" button to open the calibration module.

2. Assign Master Device:

   • Scan the QR code of the master device or manually select from available devices.

   • The selected master will be used for comparison.

3. Configure Parameters:

   • Tolerance: Choose from preset values (±0.1, ±0.2, ±0.5, ±1, ±2 °C) depending on accuracy requirements.

   • Success Threshold: Typically set to 5.

   • Interval: Set to 1 minute.

   • Sensor Mode: Select whether to calibrate:

     • Ambient only

     • Probe only

     • Both (requires more robust alignment)

4. Start Calibration:

   • Click "Start Calibration".

   • Data will begin recording every minute.

   • The system evaluates if target values fall within the defined tolerance range against the master.

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Environmental Considerations

• Ensure stable environmental conditions during calibration:

  • Fridge or Freezer: Recommended that doors remain closed.

  • Room Temperature: Both devices must be exposed to the same conditions.

• Avoid environmental disruptions (e.g., frequent door openings).

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Calibration Outcomes

• Pass:

  • Five consecutive target readings fall within tolerance of the master.

  • Calibration report is automatically generated.

  • Sensor exits maintenance mode.

• Fail:

  • No valid reading set within 2 hours.

  • Event is closed by the system.

  • Recommended Action: Replace sensor (especially for digital probe sensors).

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Post-Calibration

• A calibration report is logged and includes:

  • Master and Target device info

  • Time and result (PASS/FAIL)

  • Graph of data records and deviation

  • Calibration log with each interval's comparison and result

• Sensors exiting calibration return to operational status.

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Additional Notes

• This method is known as a reference or comparison calibration.

• Master and Target units must be placed in close proximity.

• Manual calibration methods (e.g., boiling or freezing point) are available as alternative options but should follow similar evaluation principles.

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Corrective Action for Failures

• Replace sensors that do not meet calibration standards.

• Potential causes for failure: moisture damage, aging, or physical degradation of components.