HOBO Extended Memory Motor On/Off Data Logger

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The HOBO Motor On/Off data logger records motor on and off conditions within an AC magnetic field with its internal sensor, or mechanical contact closures from external sensing devices. This data logger is ideal for tracking the usage and runtimes of motors, pumps, compressors, and other equipment. The HOBO UX90-004 Motor On/Off Data Logger is available in a standard 128 KB memory model (UX90-004) capable of 84,650 measurements and an expanded 512KB memory version (UX90-004M) capable of over 346,795 measurements.

Manufactured by: Onset
Model: HOBO Extended Memory Motor On/Off Data Logger

Services offered for this product

  • Sales
  • Rental
  • Installation
  • Calibration
  • Maintenance


Motor On/Off
State Open/Closed


Internal Motor Sensor
AC magnetic field threshold > 40 mGauss at 60 Hz
External Input
External contact input Electronic solid state switch closure or logic driven voltage output
Range 0 to 3 V DC (USB powered), 0 to 2.5 V DC (battery powered)
Maximum state and runtime frequency 1 Hz
Solid state switch closure Input Low: < 10 KΩ; Input High: > 500 KΩ
Internal weak pull-up 100 KΩ
Input impedance Solid state switch closure: 100 KΩ pull up
Resolution Pulse: 1 pulse, Runtime: 1 second, State and Event: 1 State or Event
Time accuracy ±1 minute per month at 25°C (77°F) (see Plot A in manual)
Battery life 1 year, typical with logging intervals greater than 1 minute and normally open contacts
UX90-004 128 KB (84,650 measurements, maximum)
UX90-004M 512 KB (346,795 measurements, maximum)
Download type USB 2.0 interface
Download time 10 seconds for 128 KB; 30 seconds for 512 KB
Logger Operating Range
Logging -20° to 70°C (-4° to 158°F); 0 to 95% RH (non-condensing)
Launch/readout 0° to 50°C (32° to 122°F) per USB specification
LCD LCD is visible from: 0° to 50°C (32° to 122°F); the LCD may react slowly or go blank in temperatures outside this range
Size 3.66 x 8.48 x 1.52 cm (1.44 x 3.34 x 0.6 in.)
Weight 30 g (1.06 oz)
Environmental rating IP50
The CE Marking identifies this product as complying with all relevant directives in the European Union (EU)