InTemp Bluetooth Low Energy 365 Day Multiple-Use Temperature Data Logger (CX503)


Quotes for the CX500 Series Loggers are available through the Onset Sales Team. Contact the team to obtain a quote:

Measurements: Temperature
Software: InTemp App and InTempConnect

The InTemp CX503 Bluetooth® Low Energy data logger is a multiple-use logger that records temperature data for up to a year. Designed for Cold Chain, CRT, and Frozen Shipments, the CX503 is ideal for closed-loop monitoring applications, as well as qualification testing and equipment validation.

Using the InTemp app on your mobile device, you can easily configure the CX503 with one of multiple preset configurations, or set up a custom configuration. The logger has a built-in alarm to alert you to excursions. And logger reports can be quickly downloaded to your phone or tablet and uploaded to an InTempConnectTM account, where you can analyze and export data as needed.

A 3-Point Certificate of Calibration, valid for one year from date of purchase, provides assurance that the data can be trusted when making important product-disposition decisions.

Highlighted Features:
  • Integrates with mobile and cloud platforms for a 21CFR Part 11 compliant solution
  • Enables fast, remote data transfer; ideal for clinical logistics
  • Eliminates need to open sealed containers to retrieve data
  • Shortens logger-handling times; no PC or cables required
  • Ensures secure data via encrypted technology
  • Meets GDP requirements for NIST traceable calibration

To see the full specifications for this product, please see our product manual found under the documentation tab if available.



Logger Operating Range

-30° to 70°C (-22° to 158°F) 

Radio Power

1 mW (0 dBm)

Transmission Range

Approximately 30.5 m (100 ft) line-of-sight

Wireless Data Standard

Bluetooth Low Energy (Bluetooth Smart)

Logging Rate

1 second to 18 hours

Time Accuracy

±1 minute per month at 25°C (77°F)


CR2032 (CX501) or CR2450 (CX502 and CX503) 3V lithium, not replaceable. Battery for CX501 and CX502 lasts for duration specified when logger is used within the 1-year shelf life. Battery life for the CX503 model is 1 year, typical with logging interval of 1 minute. Faster logging intervals, remaining connected with the InTemp app, excessive downloads, and paging may impact battery life. 


Multiple Use


Up to 1 year

Shelf Life

Up to 1 year


14,000 measurements 

Full Memory Download Time

Approximately 30 seconds; may take longer the farther the device is from the logger


6.9 x 4.5 x 1.1 cm (2.71 x 1.76 x 0.42 inches) 


25.5 g (0.90 oz)

Environmental Rating



The CE Marking identifies this product as complying with all relevant directives in the European Union (EU).



Temperature Sensor

Sensor Range

-30° to 70°C (-22° to 158°F) 


±1.0°C from -30° to -5°C (±1.8°F from -22° to 23°F)
±0.5°C from -5° to 50°C (±0.9°F from 23° to 122°F)
±1.0°C from 50° to 70°C (±1.8°F from 122° to 158°F)


0.04°C (0.072°F) 


<0.01°C (0.018°F) per year

Response Time

6 minutes typical to 90% in open air moving 1 m/s, unmounted