Juno IX BSX Operating Hours counter operation manual -Additional Information 

Product versions

Technical functionality

The operating hours counter uses changes in the magnetic field during operation of a machine or device to automatically detect activity periods. A 3-axis magnetic field sensor measures the local field continuously or periodically. When a characteristic change is detected (e.g., motor start, rotating parts, or current flow nearby), the electronics interpret this as an active state. Active durations are integrated to obtain cumulative operating hours.

• The sensor continuously measures the magnetic field components Bx, By, Bz in µT.
• The sampling rate can be dynamically adjusted (e.g., 10 Hz to 100 Hz), depending on desired response time and energy consumption.
• The microcontroller or a downstream signal processor analyzes the raw data.
• Monitoring of typical activity indicators:
  • Magnetic field amplitude change above a defined threshold value.
  • Frequency analysis (e.g., periodic fluctuations in rotating parts).
  • Noise or vibration patterns in the magnetic field signal.
  • If a consistent activity pattern is detected over a defined period, the status is set to "active".
• During the active state, a timer or time base (RTC or MCU-internal) runs.
• The runtime is continuously summed and stored in non-volatile memory (EEPROM or Flash), preventing data loss after power failure.
• Calibration / interference field compensation:
  • Initial calibration compensates for the local geomagnetic offset.
  • Long-term drift or external fields can be corrected using adaptive filters.
  • Optionally, the counter can be re-adjusted via a calibration signal (e.g., "known off state").

Application – Detection principle – Advantage

Electromechanical drives

Electromagnetic actuators

Energy generation & distribution

Household and industrial appliances

Vehicle and mechanical engineering

Other applications

Notes on installation

The strength and range of this field depend on several factors:

• Motor type (DC, BLDC, asynchronous)
• Housing material (magnetic or non-magnetic)
• Power and current flow
• Shielding / installation environment
• Position of the windings and magnets

As a rough guide (we recommend mounting directly on the device to be monitored to minimize interference from other machines):

Guideline table – Magnetic field and sensor distance

Interference

The magnetic field of a motor decreases with distance exponentially or approximately as 1/r³ (dipole field).

Even a few centimeters of distance can significantly reduce the motor's signal, while distant sources become barely measurable. Consequently:

• If the sensor is mounted close to the target motor (e.g., <5 cm), the influence of other machines is practically negligible.
• If the sensor is moved further away (>10 cm), the useful signal can quickly weaken and stronger external fields (e.g., from larger motors or transformers) can overlap.