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Compact Portable USB Data Loggers

Portable Temperature Data Loggers


Item# OM-91

Volume discounts available
Volume Discount Schedule
Quantity Price each
1-4 $132.20
5-9 $125.59
10-24 $122.95
25-49 $117.66
50-99 $115.01
100+ $112.37

In stock

Lead Time (If not in stock): 5 weeks
Portable Temperature Data Loggers OM-91 OM-91
  • Models for Temperature (OM-91) and Temperature/Humidity (OM-92)
  • Immediate, Delayed (Specific Date/Time) or Pushbutton Start
  • Real-Time Mode
  • User-Configurable High and Low Alarms

OM-91 Model Options

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Edit these specs to order a different model. Not all combinations are valid. Options compatible with previous selections will be in bold.

*Highlighted options are not compatible. Please select a different combination.

Measurement Type
Number of Measurements
Additional Feature
Input Type
Maximum Samples
Data Interface
Max Sampling Rate

The OM-90 Series are portable, battery operated, temperature (OM-91) and temperature/humidity (OM-92) data loggers. The OM-90 Series data loggers offer accurate and repeatable logging for temperature and relative humidity. Temperature is measured to an accuracy of ±0.3°C over the range of 5 to 60°C (41 to 140°F) and ±2.0°C over the full range of -30 to 80°C (-22 to 176°F). Relative humidity is measured to an accuracy of ±3.0% RH over the 20 to 80% RH range and ±5.0% RH over the 0 to 100% RH range. Both temperature and relative humidity are logged at a user configurable logging rate which is software selectable.

These data loggers are ideal for transportation applications where it is necessary to document that the material in-transit has stayed within particular environmental limits. High/low alarm limits can be set above or below which LED indicators will be activated so that the user can become aware that the desired transportation conditions have been exceeded.

Each data logger can be assigned a 16 character name. This can be helpful in applications where multiple data loggers are used and there is a need to distinguish between them (for example based on location).

The data logger includes a very easy to use software application. The application is used for configuration of the logger, extraction of logger data, graphically viewing data, spread sheet analysis of data and saving data to file (typically in comma separated value CSV file format) for third party applications such as Microsoft Excel. The graphical user interface is completely intuitive in terms of configuring new devices and extracting data from a field device. When the user has multiple devices requiring the same setup then a logger setup from a saved configuration file can be preloaded into the application to help expedite the process and ensure all loggers get setup identically. The application does not require any driver installations to connect to the data logger. Just install the software, run it and then connect the data logger.

    Range: -30 to 80°C (-22 to 176°F)
    Resolution: 0.01°C
    Accuracy: ±0.3°C from 5 to 60°C (41 to 140°F)
    Calibration Accuracy @ 25°C ±20°C: ±0.1°C
Humidity (OM-92 Only)
    Range: 0 to 95% RH
    Resolution: 0.01% RH
    Accuracy: ±3% over 20 to 80% RH range; ±5% RH below 20% RH or above 80% RH
    Calibration Accuracy @ 25% RH: ±1.8% RH @ 25% RH
    OM-91: 65,520 temperature measurements
    OM-92: 65,520 temperature and 65,520 humidity measurements
Start Modes: Immediate start on disconnect from PC, delayed start (scheduled date/time) or pushbutton start
Recording Mode: Stop on memory full; when data logger operation is start/stopped by user intervention via button press, last memory location is retained
Recording Interval: 1 sec, 10 sec, 30 sec, 1 min, 10 min, 30 min, 1 hr (software selectable)
Software Compatibility: Windows XP/Vista/7, 8 & 10 (32-bit and 64-bit)
Real Time Logging: Displays real time data when connected to a PC
Real Time Clock: Time automatically synced to PC
Battery Backup: Continues to keep time when off
Accuracy: 0.50 sec/day (~3 min/year)
Alarms: High and Low alarms for temperature and humidity; dedicated alarm LED indicator
LED Indicators: Alarm and status LEDs
Device ID: Each data logger can have a 16 character name assigned
Connections: USB-C port
Power: 3V lithium CR2450 battery included (user replaceable)
Battery Life: Over 4 year battery life while logging
Bypass Mode: Unit is powered from USB when connected to conserve the battery
Dimensions: 53 H x 33 W x 15 mm D (1.38 x 2.36 x 0.6')
Weight: 25 g (0.9 oz)
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Rated 5 out of 5 by from Stupidly simple to use Bought this to monitor T and humidity in my basement for suitability of wine storage. Very easy to use, super simple, data output is straight forward and versatile. Easy-peasy
Date published: 2016-09-10
Rated 4 out of 5 by from Little bit usefull This instrument works very fine. Data acquisition using this instrument if great.
Date published: 2017-12-18
Rated 5 out of 5 by from Compact - Easy to Use The mini CD that came with the product did not work. However, one call to Omega and tech support emailed me the software. Once installed, the setup was incredibility easy. I set the unit up, shipped it to my customer with instructions to install and to hit the small button on the right of unit to activate. 2 weeks later picked the unit up. Downloading the data and transferring to Excel was seamless. Highly recommend.
Date published: 2016-08-25
Rated 5 out of 5 by from Works Perfect! I purchased 2 of these about 2 months ago and they work great. I needed them to monitor temps in 2 tenant spaces.I have been using temp scribes from Grainger in the past and they are a few hundreds each. then you have to purchase chart paper and replace pencils. These are digital and can create a professional looking report to share with others if needed. For the price you can't beat them.
Date published: 2016-07-29
Rated 1 out of 5 by from Can't really comment The data logger came with a tiny CD which as everyone knows, almost no computers anywhere have a drive anymore. Went to the website to find file which was extremely difficult and once found, unable to load onto the chrome. So cant comment on items functionality cause I can not get it to work. What can be said, it thank goodness I only bought one and it was only 60 bucks!
Date published: 2016-10-31
Rated 4 out of 5 by from Great product when you can find the software I have had this about 45 days and it has preformed well. DO NOT lose the software disk that the product comes with. You will NEVER find the software on the omega site if you need to download it again
Date published: 2016-09-02
Rated 1 out of 5 by from Impossible to use. Cannot download data from unit to software. Unit will not consistently connect. Software will not work with Windows 10.
Date published: 2016-09-01
Rated 5 out of 5 by from Easy to use and configure Acurate and easy to use temperature logger; app and set up easy and simple to use
Date published: 2024-04-21
  • y_2024, m_7, d_19, h_7
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loading all QA

Are these or any other temp/RH loggers waterproof?

Asked by: acer21
Thank you for your question. Unfortunately, OM-92 or any other TEMP/RH logger we carry is waterproof.
Answered by: Raptor
Date published: 2021-03-02

Why even after i change the default directory the application always opens this directory: Local Disk (C) > Program Files(x86)> Omega PC Application > ?

Asked by: panosh
Thank you for your question. Please e-mail your questions to DAS Engr-DAS@OMEGA.COM
Answered by: Eagle
Date published: 2020-07-25

Is the OM-92 RoHS compliant?

Asked by: Daniel at Atia
The RoHS2 status of this part number has not yet been determined. OMEGA is diligently working to determine the RoHS2 status of this product, but we are still waiting to receive information from our suppliers. The status of this product may change in the near future so please check back soon. Thank you.
Answered by: Application Engineer
Date published: 2019-07-11

- lead time? - How do we read the measurement on a automation plc (analog signal 0-10V or 0-20mA or 4-20mA etc...) or is it direct modbus serial or tcp connection or other? - How often does it need calibration? - what is the life span?

Asked by: Marcio
Hello Marcio This device strictly works via USB on its own proprietary software, it does not have tcp or modbus capability.
Answered by: JA Engineer
Date published: 2019-09-25

Good Afternoon, We would like to know if the Compact Portable USB Temperature and Humidity Data Loggers has internet access and if so, what kind of security protocol is in place? Thank you.

Asked by: DannyIMP
Thank you for your question. Unfortunately, the loggers do not have internet access.
Answered by: Application Engineer PV
Date published: 2022-06-14

How come the software version downloaded is 1.2.3 but as soon as it is installed it says 1.2.19 is available and needs to be downloaded?

Asked by: panosh
Thank you for your question. Please e-mail your questions to DAS Engr-DAS@OMEGA.COM
Answered by: Eagle
Date published: 2020-07-25

Would this model be compatible in an environment with significant particulate concentrations?

Asked by: Richard R
Thank you for your question. The Om-92 logger as well as all of our Temp/Rh loggers would not work well in this environment.
Answered by: Cheetah
Date published: 2020-11-20

After connecting OM-92, Windows prompt to automatic USB driver installation and then it says "device is ready to use". But the software does not detect and illuminate the connection icon and I cannot 'read' or 'configure' it. How can I make this work?

Asked by: architecy
Please contact our DAS dept for support -1-800-872-9436 xt7775
Answered by: RaptorDTSX
Date published: 2023-09-27
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  • bvseo_bulk, prod_bvqa, vn_bulk_3.0.42
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  • clientName_omega
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