Sensor Management¶

The Sensor Management screen shows the active sensor, available sensor actions, and calibration information.

Select the sensor button in the toolbar at the top of Home.

Sensor summary¶

The summary can show the sensor family, start date, elapsed time, remaining time, expected lifetime, transmitter information, and expiry state. The exact fields depend on the configured device.

Dexcom G7-family sensors and the CGM used by the Medtrum Nano Pump do not show manual start or stop controls in xDrip4iOS. The available controls for Libre and Dexcom G6/ONE depend on the connected transmitter.

Start a sensor¶

If Start Sensor is available:

1. Confirm that the physical sensor is inserted and the transmitter is ready.
2. Select Start Sensor.
3. Enter the actual start time when requested.
4. Enter or scan the printed sensor code when the transmitter requests one.
5. Confirm the start.

Use only the code printed for the sensor. The transmitter can reject a wrong code or use it to calculate incorrect readings.

For a Dexcom G6 session, select Use Without Code when no sensor code is available. Check that No code (0000) is selected, then select Continue. If the transmitter has no active session, this starts a no-code session that requires calibrations after warm-up and periodically afterwards. xDrip4iOS shows a warning before this is confirmed.

If a Dexcom G6 sensor session is already running when the transmitter is added, select Use Without Code, then select Continue and confirm the warning. xDrip4iOS reads the existing session from the transmitter and does not start it again. See Dexcom G6 and ONE.

Scan a Dexcom G6 sensor label¶

When starting a new Dexcom G6 sensor, the sensor code screen provides four choices:

• enter the four-digit code manually
• select Scan with Camera and place the Data Matrix on the sensor label inside the frame
• select Choose Photo and choose a clear photo containing one sensor label.
• select Use Without Code when no code is available or the session is already running.

A successful scan fills in the sensor code and shows the lot number and sensor serial number from the label. Check this information before selecting Continue. You can still enter the code manually if the label cannot be read.

Scanning the label is optional. It is not needed when connecting to a G6 sensor session that is already running. Select Use Without Code for that process.

Stored Dexcom G6 sensor information¶

When this information is available, Sensor Management can show:

• Scanned Label Code when the sensor label was scanned
• Sensor Code when the code was entered manually
• Lot Number and Sensor Serial Number when they were read from a scanned label.

A confirmed no-code session shows 0000 (No-code session). xDrip4iOS uses validated data from the transmitter to keep the displayed sensor information matched to the active session.

Scan a Dexcom G7 applicator¶

When adding a G7-family sensor in Primary Mode, enter the four-digit pairing code manually, select Scan with Camera, or select Choose Photo.

Scan the Data Matrix on the current applicator. A successful scan can show the sensor code, sensor serial number, manufacture date, and expiry date. Check the information before selecting Continue.

The applicator scan is part of Primary Mode setup. It does not start a second session when the sensor is already running. Keep the current applicator until xDrip4iOS has connected successfully.

The code screen is not shown in Coexistence Mode because the other app controls the sensor connection.

Stop a sensor¶

Select Stop Sensor only when you intend to end the current sensor. Stopping a sensor is different from disconnecting or deleting its Bluetooth device.

For Dexcom G7, ONE+, Stelo, and Medtrum Nano Pump, xDrip4iOS follows the session information it receives. In Dexcom Coexistence Mode and for Medtrum, start and stop the sensor in the app that controls the system.

When calibration is available¶

The calibration control appears only when the connected CGM accepts a user calibration. Factory-calibrated systems can hide or disable it.

To calibrate:

1. Wash and dry your hands.
2. Use an approved blood glucose meter.
3. Wait until glucose is stable.
4. Open Sensor and select Calibrate.
5. Enter the meter value in the unit shown by the app.
6. Review any large-difference warning before confirming.

After a valid meter value is entered, the calibration screen checks that value together with the recent trend and sensor noise. Before a valid value is entered, Calibration Value shows Pending.... The result indicates whether conditions are good, less suitable, or unsuitable for calibration.

This is guidance only. Follow the calibration instructions for the sensor and wait when glucose is changing quickly. A separate warning appears if the entered meter value differs greatly from the current sensor reading.

Open Calibration Details to see previous calibrations and their blood glucose value, raw sensor value, slope, and intercept.

When a Dexcom G6 transmitter requests two initial calibrations, the previous calibration value can be filled in for the second entry. Check it against the current meter reading before confirming it.

For a G7-family sensor, the screen can show whether a calibration is queued, sent, processing, completed, or rejected. Wait for the current calibration to finish before entering another one. If Calibration not permitted appears, the sensor is not accepting a calibration at that time.

After a Dexcom warm-up finishes, Home and the Live Activity can show Waiting for first reading… until the transmitter sends the first glucose value. This is normally a short transition and does not mean that the sensor has restarted its warm-up.

Algorithm and Calibration Type¶

Some devices show Algorithm Type and Calibration Type after you select the device in Devices.

• Native Algorithm uses the value calculated for the sensor or transmitter.
• xDrip Algorithm calculates readings in xDrip4iOS and requires calibration.
• Standard uses the normal xDrip calibration method.
• Multi-point uses several previous calibrations and is intended for experienced users.

The available choices depend on the connected transmitter. A Calibrate button does not mean that calibration is required.

Sensor Noise¶

When enough readings are available for an active direct sensor, the Sensor Noise section shows the status for the last 30 minutes, the last 4 hours, and the last 12 hours. The possible states are Collecting data, Low, Elevated, Very High, and Extreme.

Select the Sensor Noise row to open Noise History. It opens at the widest useful range for the current sensor. Depending on the sensor age, the choices can include 1 day, 3 days, 7 days, or the complete sensor session. Lower noise values mean that the readings changed more smoothly. They do not prove that the readings are accurate.

Sensor Sensitivity changes how early the app classifies the signal as noisy:

• Sensitive warns earlier.
• Normal uses the standard limits.
• Permissive allows more variation before warning.

Changing the sensitivity does not change stored glucose or noise values. If a reading is doubtful or does not match symptoms, check it with an approved blood glucose meter.

Sensor health warnings¶

xDrip4iOS can show a warning on Home when it detects:

• very high sensor noise over a prolonged period
• readings that remain unchanged for 30 minutes
• a temporary sensor issue reported by a supported transmitter
• a sensor failure
• a transmitter failure.

Select the warning to open the relevant Sensor or device screen. The warning can be dismissed after it has been reviewed.

Optional iOS notifications for prolonged noise, an unchanged signal, and temporary sensor issues are controlled by Sensor Health Warnings under Settings > Alerts and Notifications. Sensor and transmitter failures use the Sensor/Transmitter Failure alarm configured with the other alarms.

These warnings do not confirm that a glucose value is accurate or inaccurate. Check a doubtful reading with an approved blood glucose meter and follow the instructions for the sensor.

Sensor lifetime on Home¶

The sensor line near the bottom of Home can show elapsed time or estimated time remaining. Open Settings > General > Home Screen > Sensor Lifetime and select Elapsed or Remaining. The same choice is used by the Apple Watch app. This option changes the display only. It does not extend or stop the sensor.