A real-time clock (RTC) IC provides a local time reference for a logistics device. It can help firmware attach timestamps to sensor readings, scans and other recorded events. The usefulness of those records depends on the complete system: clock accuracy, backup power, synchronization, data storage and the interpretation of each event.
What the RTC contributes
In a shipment logger, the RTC supplies time information while a sensor measures temperature or another physical quantity. A processor reads those values and stores the event. A communications interface may upload the records later. Keeping these roles separate helps define what must be tested.
An RTC does not locate a parcel, measure temperature, optimize a route or authenticate a blockchain transaction by itself. Those functions require other hardware, software and operational processes. Adding a clock also does not automatically establish regulatory compliance or prevent record tampering.
Maintain time when the main supply is unavailable
Some RTC devices support a backup supply so timekeeping can continue when the main system power is absent. This still requires an appropriate energy source and a circuit designed for the device's supply requirements.
For example, TI describes the BQ32000 as a serial RTC with battery backup and trickle charging. Its listed features include an I2C interface and oscillator-fail detection. These are device-specific capabilities: check the selected part's data sheet, backup-source compatibility and charging configuration rather than assuming all RTCs behave the same way.
During verification, interrupt the main supply and check time continuity, recovery and status reporting. A timestamp after a depleted backup supply or an oscillator failure should not be silently treated as valid.
Define accuracy and synchronization requirements
Decide how much timestamp error the application can tolerate over the expected interval between synchronizations. Review the device's accuracy specification across the intended temperature range and account for the complete timekeeping implementation.
As an illustrative calculation, a constant 20 ppm frequency error would accumulate about 1.73 seconds per day, or about 52 seconds over 30 days. This is arithmetic, not a performance claim for a particular RTC, and does not include additional system effects.
Independent RTCs do not automatically synchronize devices across a supply chain. Define an external time reference and a policy for initialization, periodic correction and operation without connectivity. Store timestamps using a consistent convention, such as UTC, and handle local-time display separately.
Make event records interpretable
A useful log needs more than a time value. Record the device identifier, event type, sequence number and any relevant sensor value. Where appropriate, retain clock-validity and synchronization status so downstream software can distinguish a trusted time from an estimated or invalid one.
If time is corrected during operation, avoid making event order ambiguous. Define how the firmware records the correction and how reporting software handles discontinuities. A separate sequence number can help preserve the order in which records were generated.
A practical validation checklist
- Check the full part number, interface voltage, operating temperature range and backup-power requirements.
- Test startup, main-power removal, backup depletion and restoration of power.
- Measure drift under representative environmental conditions and over the intended logging interval.
- Verify timestamp handling during communication outages and subsequent uploads.
- Confirm that invalid time, sensor faults and synchronization changes remain visible in the exported records.
- Test the complete logging system against its documented application requirements.
Sourcing an RTC for a logistics design
Provide the required interface, accuracy, supply conditions, package and operating range alongside the exact manufacturer part number. Confirm lifecycle status, availability and traceability for the proposed supply. For a sourcing enquiry, send the specification and quantity through the Informic contact page.
