Technical Justification Note · Technical and technological choices
Why these technical choices
This note explains and justifies the technical choices for the online vibration monitoring system proposed for Tongon: each choice addresses a precise operational need, anchored on the applicable standards, rather than technological overkill.
1 · Purpose and principles
Four principles govern the design
Fit-for-purpose
Each measurement point is justified by a real failure mode of the machine concerned; nothing is instrumented "on principle".
Normative grounding
Thresholds, severity and analysis methods are based on applicable ISO standards.
Openness
Standard protocols and raw data export: the client remains owner and operator of its data, without dependency on a closed platform.
OT security
The online architecture is segmented and secured according to IEC 62443 principles.
2 · Regulatory framework
Reference standards
| Reference | Purpose / scope |
|---|---|
| ISO 20816 | Evaluation of mechanical vibration by measurements on non-rotating parts; severity zones A/B/C/D (supersedes ISO 10816). |
| ISO 13373 | Vibration condition monitoring and diagnostics of machines: measurement procedures (part 1), data processing and analysis (part 2). |
| ISO 17359 | General guidelines for condition monitoring and diagnostics of machines. |
| ISO 13379 | Data interpretation and diagnostic techniques (support for fault / symptom correlation). |
3 · Justification matrix
Measurement point ↔ monitored fault ↔ machine
The heart of the justification: for each equipment family, the selected measurement points, the monitored failure mode and the associated analysis technique.
| Component | Measurement point | Monitored fault | Technique / indicator |
|---|---|---|---|
| Ball mills | |||
| Trunnion bearings | Bearing, radial H/V | Wear, lubrication fault | RMS velocity (ISO 20816) + envelope / acoustic emission (low speed) |
| Ring gear – pinion | Pinion housing, radial | Meshing fault, teeth | GMF and sidebands (HF spectrum) |
| Gearmotor | Motor / gearbox bearings | Bearings, misalignment, unbalance | Envelope (bearings) + 1x / 2x |
| Structure / foundation | Base, radial | Mechanical looseness | 1x harmonics (waveform) |
| Cyclone feed pumps | |||
| Bearings | Bearings, radial H/V + axial | Spalling, seizure | HF envelope (BPFO / BPFI / BSF / FTF) |
| Impeller / hydraulics | Discharge flange, radial | Unbalance (erosion), recirculation | Radial 1x + vane passing (n·RPM) |
| Coupling | Bearings, axial + radial | Misalignment | 2x, marked axial component |
| Pump casing | Volute, radial | Cavitation | HF broadband noise ("haystack" spectrum) |
| Crushers (jaw type) | |||
| Eccentric shaft | Bearings, radial | Bearings, clearance | Envelope + waveform |
| Toggle / jaws | Frame, radial | Shocks, impacts, clearance | Time waveform (crest factor, kurtosis) |
| Flywheel | Flywheel bearing, radial | Unbalance | 1x |
| Transmission | Motor mount | Belts (tension, fault) | Belt frequencies / sub-harmonics |
4 · Measurement chain
Sensors and bandwidths by equipment type
The choice of sensors and their mounting derives from the frequencies to observe and the environment of each machine. Stud mounting is preferred wherever the required bandwidth demands it.
| Equipment | Sensor & mounting | Bandwidth | Indicators / processing |
|---|---|---|---|
| Ball mills | Low-frequency, high-sensitivity IEPE accelerometer (~500 mV/g), stud mounting | ≈ 0.2 Hz – 10 kHz | Order analysis, envelope, acoustic emission / stresswave (low speed) |
| Cyclone pumps | Standard IEPE accelerometer (~100 mV/g), stud mounting; radial H/V + axial | ≈ 1 Hz – 15 kHz | RMS velocity, bearing envelope, vane passing & cavitation monitoring |
| Crushers | Rugged high-range accelerometer (~100 mV/g, ±50 g), IP67 housing, shielded cable | ≈ 1 Hz – 10 kHz | Waveform (crest, kurtosis), envelope, spectrum |
5 · Architecture & cybersecurity
A segmented and open online architecture
The system is permanent (online sensors → concentrators → gateway → supervision server). Its integration into the site network follows a logic of security and openness.
OT segmentation
The CMS resides in a dedicated OT zone (VLAN), isolated from the office network; flows controlled toward the PLC / supervision per the IEC 62443 zones and conduits model, industrial firewall.
Openness / anti-lock-in
Communication via standard protocols (Modbus TCP, OPC-UA) and export of raw data (waveforms and spectra in open formats). Diagnostics remain possible even without the vendor platform.
Access control
Authentication, rights management, logging, controlled updates and backups.
This OT dimension is a core area of expertise for INOVATEC: it turns a security requirement often overlooked by sensor suppliers into a guarantee built in from the design stage.
6 · Controlled scope
What we retain, what we exclude
The credibility of an instrumentation offer is judged as much by what it excludes as by what it proposes. Our trade-offs are explicit.
| Retained — justified by the need | Deliberately excluded — to avoid overkill |
|---|---|
| Instrumentation of critical circuit machines (mills, pumps, crushers) | Systematic instrumentation of non-critical machines |
| Measurement points justified one by one by a failure mode | Redundant sensors providing no diagnostic gain |
| Techniques adapted to each physics (envelope, order, waveform) | Advanced software functions not used by the teams |
| Open protocols and exportable raw data | Closed proprietary solutions creating dependency |
7 · Design review
Co-building the choices rather than imposing them
Before deployment
Joint design review
Joint review of the measurement plan with Instrumentation before deployment.
Technical visit
On-site validation
Validation of measurement points with the Instrumentation manager during the technical visit.
Proof of value
Pilot on one machine
Demonstration of value through early detection of a real fault before generalization.