Maintenance

Maintenance Procedures

Access maintenance functions via the Maintenance button (wrench icon) in the navigation bar. The modal is organized into cards for device management, system status, time synchronization, and geolocation.

Filter Change Procedure

The filter is not identical on both sides.

• Identify the side with markings (black line, dot, or circles).
• The marked side must face UP (towards the LEDs/light source in the upper optical chamber).

Warning: Incorrect orientation (marked side down) results in ~30% measurement error.

Procedure:

1. Stop any running session.
2. Unscrew the top cap of the optical chamber.
3. Remove the saturated filter.
4. Insert a new filter with markings facing up.
5. Screw the cap back on (hand-tight).
6. Check hose (if used): ensure the air hose remains connected to the inlet port.
7. Run Calibration (required).

Calibration

Filters vary slightly in optical density. Calibration balances the sensor signal against the reference signal for the specific filter currently installed.

1. Go to Maintenance > Calibrate Device.
2. Ensure a new and clean filter is installed.
3. Click "Yes."
4. A progress bar appears. The device adjusts LED intensity per channel using binary search to find optimal duty cycles.
5. Wait for "Calibration Successful" before starting a new log.

Technical detail: Calibration determines the per-channel correction factor K = Ref_avg / Sen_avg and stores it along with optimal LED duty cycles. The ADS1220 ADC samples at 200 samples/sec and targets the 0.5–3.8V sensor range. Calibration typically takes 30–60 seconds.

Data Management

Data is stored on the device's internal storage (with SD card as optional backup).

1. Click Log Files.
2. Logs (>2 KB): Valid measurement sessions. Download these for analysis.
3. Logs (<2 KB): Failed starts or very short tests — can typically be deleted.

Downloads available as CSV (for analysis), PNG, or SVG (for printing). CSV files use semicolon separation with dot as decimal divider.

Backup: Internal storage is not archival. Download data to a secure location regularly.

Storage management: The device has ~2 MB internal flash for logs. Warning at 512 KB free, critical at 32 KB. Old logs are auto-deleted when critical threshold is reached. Empty files are cleaned on startup.

Device Management

Routine Maintenance

• Calibrate Device: Adjusts LED duty cycles. Required after each filter change.
• View System Logs: Opens the application log for diagnosing issues. Logs are grouped by category: hardware, measurement, system, network.
• Download Logs: Downloads full system logs for troubleshooting or support.

System Operations

• Reboot Device: Restarts the device.
• Shutdown Device: Safely powers off to prevent data corruption. Always use this before unplugging. If the device loses power during a session without proper shutdown, it will automatically resume measurement on next boot.
• Update Firmware: Opens a dialog to manually upload a firmware file (.tar.gz). The device also checks for updates automatically every 6 hours and notifies you when one is available.
• Factory Reset: Permanently erases all measurement logs, WiFi credentials, calibration data, and device settings. A slide-to-confirm gesture is required. The device reboots into factory state.

System Status

Displays device information:

• Device ID: Unique hardware identifier (MAC address).
• Device Name: Current network hostname.
• Software Version: Installed firmware version.
• Free Memory: Available system memory.
• Last Calibration: Timestamp of the most recent calibration.

Time Synchronization

Critical for accurate data timestamps, especially for devices without internet.

• Browser Time / Device Time: Displayed for comparison.
• Sync: If mismatch exceeds 10 seconds, a sync button appears to synchronize the device clock with your browser.

Devices connected to the internet sync automatically via NTP. Modem-based time sync (CLTS) is also supported when a 4G modem is connected.

Geolocation

When location services are active (Settings > Measurement > Location), a Geolocation card displays:

• Location: Latitude/longitude with source (GPS, cell tower, or IP-based) and accuracy indicator.
• Altitude (barometric): Derived from the pressure sensor.
• Altitude (GPS) & Speed: Shown when a GPS module is connected and has a fix.

The location input supports multiple formats: 48.2082, 16.3738 — 48.2082 16.3738 — (48.2082; 16.3738) etc.