IIoT · 10 min read · Updated November 2026
Wireless Vibration Sensors: From ISO 10816 Thresholds to Prescriptive Maintenance
Battery-powered vibration and temperature sensors that cost a few hundred dollars have put condition monitoring on motors and pumps that would never have justified a wired system. What the sensors actually measure, how to set alarms that mean something, which platforms turn data into work orders, and the honest limits of the technology.
Condition monitoring used to mean a route-based technician with a handheld analyser every quarter, or a wired online system on the plant's five most expensive machines. Since about 2020 a third tier has appeared: wireless MEMS-based sensors — SKF Enlight, Emerson AMS Wireless Vibration Monitor, Fluke 3563, ifm VVB, Banner QM30VT with DX80 radios, Siemens SITRANS MS200, Yokogawa Sushi Sensor, i-ALERT from ITT and many others — that mount on a magnet, run years on a battery, and send velocity, acceleration and temperature every few minutes to a gateway. We have installed several hundred on pumps, fans, compressors and conveyors; this is what we tell customers before they buy a pallet of them.
What the sensor measures
A wireless vibration sensor contains a MEMS accelerometer (sometimes three-axis), a temperature sensor, a radio and a battery. It samples acceleration at a few kHz for a short window, computes overall values on board — velocity RMS in mm/s over 10–1,000 Hz per ISO 20816 (the successor to ISO 10816), acceleration RMS or peak, kurtosis or crest factor as a bearing indicator — and transmits those values periodically. Some sensors also transmit raw waveforms or FFT spectra on demand or on alarm, which is where the diagnostic value lies. The key specifications to compare: frequency range (a 10–1,000 Hz velocity measurement sees unbalance and misalignment; bearing defects need acceleration to 5–10 kHz), sampling resolution, number of axes, transmit interval versus battery life, and whether spectra are available or only overall values.
Setting alarms that mean something
ISO 20816-3 gives evaluation zones for velocity RMS by machine class — for a 15–300 kW motor on a rigid foundation, roughly: zone A/B boundary 2.8 mm/s (newly commissioned), B/C boundary 4.5 mm/s (unrestricted long-term operation limit), C/D boundary 7.1 mm/s (damage may occur). These are starting points, not alarm settings. The method that works:
- Baseline each machine for two to four weeks after installation; record mean and standard deviation of velocity and acceleration per operating state (speed, load).
- Alert at baseline + 2σ or 1.5 × baseline, whichever is higher, and alarm at 2–2.5 × baseline, capped by the ISO zone C/D limit. A machine that lives at 1.5 mm/s should alarm at 3–4 mm/s, long before the 7.1 mm/s zone limit.
- Trend acceleration and bearing indicators separately: bearing defects show in high-frequency acceleration months before velocity moves.
- Use temperature as a second vote: a bearing-temperature rise with an acceleration rise is a bearing; a velocity rise with no temperature change is more likely unbalance, misalignment or looseness.
- Suppress alarms by state: start-up, VFD speed changes and cavitation events produce transients. Feed machine state (running/speed) from the PLC into the platform.
Architecture options
| Option | Sensors to gateway | Gateway to system | Fits |
|---|---|---|---|
| Vendor cloud platform | Proprietary radio or Bluetooth LE to vendor gateway | Cellular/Ethernet to vendor cloud; dashboards, alarms, analytics included | Plants without a SCADA/CMMS integration team; fastest start |
| Wireless to plant SCADA | ISM/Sure Cross to a DXM700-class controller, or WirelessHART to a gateway | Modbus TCP / OPC UA to SCADA; alarms in the plant system | Plants that want vibration in the same alarm list as process alarms |
| IO-Link wired sensors | Cable to an IO-Link master | PROFINET/EtherNet/IP to PLC plus IoT core to IT | Machines and skids where a cable is easy; continuous data, no battery |
| Edge analytics | Any of the above | Edge computer runs the analytics, publishes MQTT to CMMS/cloud | Plants with an IIoT architecture and data-ownership requirements |
From alarm to work order: the prescriptive step
The 2026 trend is prescriptive maintenance: the platform not only alarms but proposes the action — "outer-race bearing defect, stage 2, replace within 4–6 weeks; order SKF 6310" — and raises a work order in the CMMS. Vendor platforms do this with built-in diagnostic rules and increasingly with ML models trained on fleet data; the quality depends on the sensor delivering spectra, on correct machine metadata (bearing numbers, speed, drive type) and on someone validating the first few diagnoses. In our experience the biggest gains come from the unglamorous part — the machine list with bearing part numbers and the CMMS integration — not from the algorithm.
Limits to be honest about
- Wireless sensors sample intermittently; a sudden failure between samples is missed. Critical, fast-failing machines still need online wired systems.
- Overall values alone diagnose little. Buy sensors that give spectra, at least on alarm.
- Mounting matters: a magnet on a painted curved surface attenuates high frequencies. Clean, flat, as close to the bearing as possible, and the same spot every time.
- Radio planning: metal-dense plants need gateways closer than the datasheet range; walk-test before buying the full quantity.
- Batteries are a maintenance item; plan the replacement cycle in the CMMS.
A sensible starting project
Twenty to forty sensors on the pumps and fans whose failure actually stops something, one gateway architecture chosen for how the plant wants alarms delivered, a machine list with bearing numbers, a 30-day baseline, and a monthly review for the first six months. We supply the sensors, gateways and edge/IO-Link hardware from the manufacturers we document, help set the baselines and integrate alarms into SCADA or a CMMS, and are candid about which machines need more than a wireless sensor.
Need engineering help with this?
Our engineers apply this to real projects every week — selection, specification, commissioning. Send your question or a part number.
Quick answers
Which standard should I use for vibration limits, ISO 10816 or ISO 20816?
ISO 20816 replaced ISO 10816 part by part; the numerical zone boundaries for common machine classes are essentially unchanged. Use ISO 20816-3 for industrial machines above 15 kW and treat the zones as starting points, then set alarms from each machine's baseline.
How long do the batteries last?
Typically 2–5 years at one measurement every 5–15 minutes; shorter if spectra are transmitted frequently or the transmit interval is one minute. Check the datasheet assumptions and log the replacement date in the CMMS.
Can wireless vibration data go into my existing SCADA?
Yes. Gateways such as the Banner DXM700 or WirelessHART gateways expose values over Modbus TCP or OPC UA, so the overall values and alarms appear in SCADA; spectra usually stay in the vendor or edge platform.