ONSET HOBO UX90-004 Motor On/Off Data Logger

OverviewThe HOBO Motor On/Off data logger records motor on and off conditions within an AC magnetic field with its internal sensor, or mechanical dry contact closures from external

  • Product Name:ONSET HOBO UX90-004 Motor On/Off Data Logger
  • Model:UX90-004
  • Maunufactor:Onset
  • Country:USA


The HOBO Motor On/Off data logger records motor on and off conditions within an AC magnetic field with its internal sensor, or mechanical dry contact closures from external sensing devices. This data logger is ideal for tracking the usage & runtimes of motors, pumps, compressors, and other equipment. 

Item number UX90-004M has been discontinued.

Highlighted Features

  • Dual internal motor sensors gives better sensitivity for well-shielded motors

  • External input for measuring mechanical contact closures when signal strength is low

  • Auto-calibration of ON and OFF thresholds ensures reliable readings

  • Compatible with HOBOware and HOBOware Pro software for logger setup, graphing and analysis

In what environment does this data logger operate?

This data logger operates in an indoor environment.

What measurements does this data logger support?

The UX90-004 data logger supports the following measurements: Motor On/Off, Runtime and 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

UX90-002- Temperature Specification ChartTime accuracy:      ±1 minute per month at 25°C (77°F) (see Plot A)

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)