1. Survey the tank before touching a drill
Every tank is measured before installation: internal depth, wall thickness, baffle positions and the true shape of the sump. Cylindrical tanker compartments, saddle tanks and rectangular generator day-tanks each produce a different volume-per-centimetre curve, so a single linear conversion is never acceptable.
We record the vehicle on a level surface and mark the reference plane. All subsequent readings are tied to that plane so the calibration table remains reproducible during any later audit.
- Internal depth measured with a dip rod, not from OEM specifications
- Baffle and sump positions logged to explain non-linear zones
- Mounting point chosen away from filler turbulence and return lines
2. Cut the probe to the tank, not the tank to the probe
Escort probes are supplied over-length by design. The tube is cut to leave a controlled clearance above the sump so sediment never bridges the electrodes, and the top of the probe stays clear of the maximum fill line to avoid clipping at full tank.
After cutting, the probe is re-terminated, sealed and its empty-tank frequency captured. That empty reference becomes the anchor of the whole table.
3. Litre-by-litre reference filling
The tank is drained, then filled in fixed increments through a calibrated meter. At every step the raw sensor value and the metered volume are recorded together, building a multi-point table rather than a two-point line.
Denser point spacing is used at the bottom and top of the tank, where geometry changes fastest and where theft attempts are most likely to be disguised.
- 20 to 40 calibration points on a tanker compartment
- Values entered as a piecewise table in Wialon, not a linear formula
- Fill and drain runs compared to expose hysteresis
4. Drift, temperature and motion verification
Diesel dielectric constant moves with temperature, and sloshing during motion adds noise. The commissioning run therefore includes a static soak test, a loaded road test and a filtered-versus-raw comparison so reporting thresholds are set above real-world noise instead of below it.
Only when the same physical volume reads consistently across cold morning and hot afternoon conditions is the unit accepted for handover.
5. Documented handover
Each vehicle leaves with a calibration certificate: tank profile, probe serial, point table, deviation percentages and the technician signature. That document is what allows a fuel claim to survive a dispute with a transporter or an insurer.
Key takeaways
- Two-point linear calibration is the single biggest cause of unreliable fuel data
- Probe cut length governs both sediment immunity and full-tank clipping
- Temperature and motion testing must precede alert threshold configuration
- A signed calibration certificate turns telemetry into evidence
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Our engineers scope, install, commission and maintain across Burundi, Tanzania and DR Congo.