How to use the automatic fault detection

The NEON Vibration Sensor, using communication protocol v4 and onwards, includes as one of its features the Machine Fault Indicator, which allows automatic detection of common faults and bearing faults. The machine_fault_indicator schedule can be used to request the analysis of a specific fault type. Currently, we can distinguish between two fault types, both of which have their own categories.

Please note that it is an indication of a fault triggered by the detection of signs that are often associated with a certain category of machine faults. The user has the option to request a spectrum on fault if they require more proof. It is advised to look at the relevant spectrum when such a notification is received.

Common Faults Detection

The Machine Fault Indicator can detect common faults like unbalance, misalignment, or mechanical looseness by analyzing the velocity FFT spectrum measured by the NEON Vibration Sensor.

Scheduling a machine fault indicator with fault_type=common_fault will lead to analysis of 3 fault categories (nx, 2x, 1x). The category names are based on what harmonics of the rotating speed (x) are dominant in the spectrum.

• Nx are faults such as looseness, where many harmonics of the rotating speed are present.

• 2x are faults such as misalignment, where 2 harmonics of the rotating speed are present.

• 1x are faults such as imbalance and critical speed, based on the harmonic of the rotating speed.

• None when there was no indication of any of the faults listed above.

The message will always contain the set of 10 harmonics of the rotating speed that it found.

Bearing Faults Detection

The Machine Fault Indicator can detect bearing faults by analyzing the envelope spectrum measured by the NEON Vibration Sensor.

Scheduling a machine fault indicator with fault_type=bearing_fault will lead to the analysis of bearing faults. If no indication of a fault was found, it will return "None". Bearing faults are analyzed in the envelope spectrum, which is calculated using a bandpass filter and the Hilbert transform. The message will always contain the set of 10 harmonics with the highest overall amplitude (which cannot be those of the rotating speed.

Configuration

The NEON Vibration Sensor can be configured to detect common faults and bearing faults automatically by sending the following structure to the device.

{
  "message_name": "schedule_update_request",
  "message_version": 0,
  "slot": 0,
  "command": "set",
  "timing": "360", //How often to measure the machine for bearing faults
  "triggered_on_button_press": false,
  "send": true,
  "task": {
    "type": "vb_machine_fault_indicator",
    "version": 1,
    "enable_spectrum_on_fault": true, //Send an FFT spectrum if a fault is detected
    "spectrum_hold_off_hours": 0,
    "spectrum_time_to_transmit_min": 0,
    "axis": "all",
    "range": "gscale_16",
    "f_min": 10,
    "f_max": 6600,
    "f_min_envelope_filter": 500,
    "f_max_envelope_filter": 6600,
    "machine_fault_selection": { //Selection for the Machine Fault Indicator
      "common_faults": true, 
      "bearing_faults": true
    },
    "send_condition": {
      "value_type": "always",
      "threshold": 0
    }
  }
}

The general recommendation is to set up the Machine Fault Indicator every 6, 12, or 24 hours for all axes with the vibration parameters (range, sample speed divider, fmin, fmax) required for the machine being monitored.

For more details about how to configure a device, please see Configure a Device.