Short answer: most manufacturers and quality systems use a 12-month interval for accelerometers and other vibration sensors. Shorten it for critical, harsh-environment or recently damaged sensors; lengthen it only when your own calibration records show the sensor stays in tolerance.
Why accelerometers drift
A piezoelectric accelerometer has no moving parts to wear out, so a healthy sensor is very stable. Sensitivity changes come from what happens to it in service:
- Shock. A drop onto concrete or a hammer blow during mounting can crack the crystal or shift the internal preload. Sensitivity changes, sometimes by a lot.
- Temperature. Running near or above the rated temperature ages the crystal and the built-in electronics of IEPE sensors.
- Moisture and connectors. Water in a connector or cable changes the bias voltage and adds noise long before the sensor fails outright.
- Mounting. A damaged base, a bent stud or a dirty mounting surface changes the high-frequency response even when the sensor itself is fine.
Calibration finds these changes before they distort trends, trigger false alarms or, worse, hide a real fault.
What shortens or extends the interval
| Factor | Calibrate more often when… | Longer intervals are reasonable when… |
|---|---|---|
| Criticality | The sensor protects or trips a machine, or feeds a safety system | It is one of many route-based measurements |
| Environment | High temperature, washdown, chemicals or frequent shock | Clean, temperature-stable indoor mounting |
| Handling | Portable sensors carried on routes or moved between machines | Permanently mounted and undisturbed |
| History | It has been found out of tolerance, dropped or repaired | Several consecutive calibrations show little change |
| Requirements | A customer, regulator or quality system sets a fixed interval | Your own documented procedure allows intervals based on history |
Standards don’t prescribe one interval. ISO/IEC 17025 leaves it to the user, and guidance such as ILAC-G24 / OIML D 10 describes how to set and adjust intervals from evidence.
Setting intervals from calibration history
1. Start at 12 months
Use the manufacturer’s recommendation, usually one year, for new sensors.
2. Record “as found” results
Always record sensitivity before any adjustment. As-found data is what tells you whether the interval is working.
3. Adjust from the trend
If a sensor is found well inside tolerance several times in a row, you can extend its interval in steps. If it is found out of tolerance, shorten the interval and review the data it produced since the last good calibration.
Group identical sensors in identical service and use their combined history: one drifted sensor in a family is a warning for the rest.
Field checks between calibrations
A full lab calibration (for example by comparison to a reference accelerometer per ISO 16063-21) checks sensitivity across frequency. Between those, a quick field check on a portable calibrator catches most problems in minutes:
- Sensitivity at a reference point. Mount the sensor on the shaker and compare its output to the calibrator’s reference at the frequency and level on the sensor’s calibration certificate, so you can compare like with like.
- Bias voltage. For IEPE sensors, a bias outside the datasheet range points to a cable, connector or amplifier problem. See our bias voltage troubleshooting guide.
- A few frequencies. Check low, mid and high points to catch mounting and resonance problems.
- The whole channel. Vibrate the installed sensor and confirm the monitoring system shows the right value. This checks cabling, scaling and configuration, not just the sensor.
The AT2030 gives you a traceable reference vibration from 5 Hz to 10 kHz to compare against. The AT2040 also powers and reads the sensor, shows live sensitivity and bias, and runs multi-point tests that end in a PDF certificate.
Interval estimator
Suggest a starting interval
A rule of thumb based on the factors above. Your quality system and calibration history take priority.
FAQ
How often should accelerometers be calibrated?
Typically every 12 months. Calibrate critical, harsh-environment or recently damaged sensors more often, and extend the interval only when calibration history shows the sensor stays in tolerance.
Does ISO 17025 say how often to calibrate?
No. ISO/IEC 17025 requires calibration to be traceable but leaves the interval to the user. Guidance such as ILAC-G24 / OIML D 10 explains how to set intervals from evidence.
Should I recalibrate an accelerometer after dropping it?
Yes. Shock can crack the crystal or shift its preload. Check sensitivity and bias before putting it back in service.
What is a field check, and does it replace lab calibration?
A field check compares the sensor to a traceable portable calibrator at one or a few points. It catches most failures quickly, but it does not replace a full lab calibration across the frequency range.
How often should the portable calibrator itself be calibrated?
Usually once a year, by an ISO/IEC 17025 accredited lab, so its own reference stays traceable.
Related: How to choose a portable vibration calibrator · How to calibrate an IEPE accelerometer · Calibrator recalibration service