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Portable USB Temperature and Humidity Data Loggers with Display

Portable Temperature/Humidity Data Loggers with Display


Item# OM-71

Volume discounts available
Volume Discount Schedule
Quantity Price each
1-4 $255.18
5-9 $242.42
10-24 $237.32
25-49 $227.11
50-99 $222.01
100+ $216.90

In stock

Lead Time (If not in stock): 9 weeks
Portable Temperature/Humidity Data Loggers with Display OM-71 OM-71
  • Compact, Light Weight, Easy-to-Use
  • User Selectable Stop on Memory Full or Memory Rollover for Continuous Recording
  • PC Delayed Start or Pushbutton Recording Control
  • Read Recorded Data on Logger Display

OM-71 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
Input Type
Maximum Samples
Additional Feature
Data Interface
Max Sampling Rate

The OM-70 Series of portable temperature and temperature/humidity data loggers are easy-to use, versatile devices which can be used for a wide range of logging applications including coolers, freezers, greenhouses, museums, laboratories, shipping containers, warehouses, environmental monitoring and food storage.

These data loggers are capable of sampling as fast as once per second or as slow as every 18 hours. Models OM-71 and OM-72 can store a total of 43,344 temperature measurements in memory. Model OM-73 can store a total of 43,344 measurement points for temperature only or 21,672 points of temperature, humidity and dew point. The model OM-74 thermocouple data logger can store 32,638 temperature samples. Easy-to-use Windows software is included with each data logger.

The software is a full-featured program that allows you to set up all data logger functions including sampling rate, logging duration, start mode, logging mode, and high and low temperature alarm values. Once data has been logged, the program then allows you to download data from the logger, plot the data and export the data to an ASCII text or Excel file format for further analysis.

Software Features Include:
• Data summary to read statistics and alarm information in a simplified report format.
• Data listing for tabular view of detailed dates, times and values of recorded data.
• Graph function displays data in clear graphical format.
• Zoom magnifies data with powerful zoom and autoscale functions.
• Autoscale function fits data to the screen or allows user to manually enter their own values.
• Graphical Cursor displays exact data of any point in the graphical display.
• Export data in text or Excel format.
• Print graph or text data with print preview and setup options.
• Logger configuration allows easy set up and launch of data loggers with immediate or delayed start, preferred sample rate, alarm setup, and custom ID.
• Password protected calibration function automatically stores with parameters in device or restores factory defaults. A calibration Window is provided in the software to simplify the calibration procedure.
• Status windows display unique ID of logger, battery voltage, memory used, sample rate, duration, alarm condition and logging status.
• Menu Bar along the top of the screen provides one click access to software functions.

OM-71, OM-72, OM-73
Ambient Temperature Measurement Range
(Models OM-71, OM-73):
-20 to 70°C (-4 to 160°F)
External Sensor Temperature Measurement Range
(Model OM-72):
-40 to 70°C (-40 to 160°F)
Storage Temperature: -40 to 77°C (-40 to 170°F)
Temperature Accuracy: ±0.5°C (±1°F), from -17 to 50°C (1 to 122°F)
Temperature Resolution: 0.1°C (0.05°F)
Relative Humidity Range
(Model OM-73):
0 to 99% RH non-condensing
Relative Humidity Accuracy
(Model OM-73):
±2% RH from 10 to 90% RH @ 25°C (77°F)
Relative Humidity Resolution
(Model OM-73):
0.05% RH

Display Temperature Resolution:
0.1°C (0.2°F) up to 199.9 °C or °F,
1°C (1°F) above 200 °C or °F
Logged Temperature Resolution: 0.1°C (0.2°F)
Thermocouple Impedance: 50 ? max for specified accuracy
Cold Junction Temperature Accuracy: ± 0.3°C (±0.5°F)
Operating Temperature: -18 to 55°C (0 to 131°F)
Storage Temperature:-30 to 80°C (-20 to 175°F)

Sample Rate:
1 second to 18 hours user selectable
Alarm Settings: Over/under alarm with visual indication
LCD Display: Displays temperature, date, time,
alarm condition recording status and battery condition
Time Accuracy: ±100 ppm @ 24°C (75°F)
Measurement Capacity: OM-71, OM-72, OM-73:
Non-volatile memory; 43,344 samples
for temperature only, or 21,672 samples for temperature,
humidity and dew point (Model OM-73); OM-74; 32,638 temperature samples
Recording Control: Start on button press, immediate after setup,
or at a user specified date and time
Recording Mode: Stop on memory full,
or continuous recording with memory rollover
Minimum System Requirements: 8MB of RAM, 2MB of disk space,
800 x 600 resolution, 1 free USB port
Software Compatibility: Windows XP/Vista/7 and 8 (32-bit and 64-bit)
Interface: USB 2.0
Power: OM-71, OM-72, OM-73: 3 V CR2032 lithium battery (included);
OM-74; 3 AAA batteries (alkaline or lithium)
Battery Life: 3 years (average)
OM-71, OM-72, OM-73: 6 H x 5.7 W x 1.3 cm D (2.36 x 2.24 x 0.51')
OM-74: 5.7 H x 5.5 W x 3.0 cm D (2.25 x 2.15 x 1.2')
OM-71, OM-72, OM-73:
91 g (3.2 oz)
OM-74: 62 g (2.2 oz)
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Rated 4 out of 5 by from Solid Logger (for the most part) I have bought roughly 10 of these over the past 8 years. We use them for monitoring the temperature and humidity of a control room for Concrete testing. For the most part these are solid units. I have had a couple that had the screens go out on them after 5 years or so and the plastic gets discolored when exposed to sunlight. One had the temperature go out and it only lets you calibrate it slightly from the original settings. That said these generally work great with those few exceptions. The program for the PC is easy to use and understand. I will continue to purchase these as needed.
Date published: 2016-03-11
Rated 4 out of 5 by from works great. easy to use. had to guess where to get software to download data to but figured it out eventually. USB connection works easily, but I would now pay a little mre for a wireless download option
Date published: 2018-03-14
Rated 4 out of 5 by from Good for general monitoring We really like the OM-70 series for monitoring temperature and humidity during our testing. They work well and the software is easy to use. The only issue we have is that they will not stay in calibration in the lower 10 degrees C of the published range and there is no adjustment to correct this. We calibrate them to 10 C above the published low range and they work well there.
Date published: 2017-11-16
Rated 5 out of 5 by from Ok OK it is an small product but is very powerfull. I like it!
Date published: 2020-11-16
Rated 5 out of 5 by from Works as promised These are great for measuring temperatures in a concrete cure room that we have for ASTM C511.
Date published: 2020-08-04
Rated 4 out of 5 by from Good value for a stand alone data logger I have bought these many times over the years and appreciate the updates to the user interface. The data loggers are very robust and accurate. I would give this a 5 star review if there was a version of the software that would also calculate Heat Index as part of the standard data output. Very useful for safety studies.
Date published: 2019-07-11
Rated 1 out of 5 by from NOT A PRODUCT YOU WANT TO PURCHASE!!!! OMEGA will not support this product. You have to send over $65.00 for the software to operate the product. DO NOT PURCHASE THIS PRODUCT!!!
Date published: 2018-06-07
Rated 4 out of 5 by from Reliable instrument Have one of this working for more than 4 years in a curing room in the middle of the Mojave desert. No problem at all.
Date published: 2017-09-01
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Does the equipment come with a calibration certificate?

Asked by: Mildred
Hello, thank you for your question. OM-71 does not include a calibration cert, if a certification is needed then you should order OM-71-NIST instead. This part number includes the same logger plus a NIST traceable calibration.
Answered by: DA Engineer
Date published: 2023-06-15

The data sheet says that the data loggers are compatible with windows 7 and 8 but does not mention Windows 10. Would it work with Windows 10?

Asked by: brandon89
Thank you for your question. The software is compatible with Windows 10.
Answered by: Application Engineer PV
Date published: 2022-12-13

Is the OM-72 approved through the VFC program for vaccine monitoring in refrigerators and freezers.

Asked by: Anonymous
Hello I am sorry it is not.
Answered by: JA Engineer
Date published: 2022-01-20

Using the interface software, is there any way I can live export data when new points come in, or do I have to manually export every time I want the data?

Asked by: nickm
Thank you for your question. Once the logger has started you can auto-load date to software and then you would have to manually Export to Excel. It will not import real-time into Excel.
Answered by: Application Engineer PV
Date published: 2021-12-22

Is there a list of serial commands for this instruments? I am looking to communicate with the instrument over serial interface from a python environment.

Asked by: Ohtani20201121
Thank you for your question. There are no serial commands available just the provided software.
Answered by: Application Engineer PV
Date published: 2022-01-20

I have 3 OM-73. One of them consistently reads a battery level 0.25V below the other two (confirmed by switching and reading multiple batteries). It is always in a low battery state because of this. Can it be repaired?

Asked by: Toni1234
Thank you for your question. We will require more information to help on this question, please email the DAS team at DAS@OMEGA.COM
Answered by: Application Engineer PV
Date published: 2022-03-23

I would like to know what is the maximum distance the logger can be from the sensors in the wired version? Is it possible to have the probes place approx. 20 meters from the device? will the information carry that far?

Asked by: Danielsan
The OM-71 has a built in sensor it does not have a remote sensor. Take a look at the OM-74 that has a external thermocouple connection so you can use a remote probe and 20 meters is no problem for a thermocouple.
Answered by: cw1engineer
Date published: 2019-11-14

When I set up my OM-74, the month & day are correct, but the year shows on the logger as 2011 instead of 2022. The OM-70 PC software correctly shows 2022, but the logger still says 2011. How do I correct the year?

Asked by: OM74
Thank you for your question. We will require more information to help on this question, please email the DAS team at DAS@OMEGA.COM
Answered by: Application Engineer PV
Date published: 2022-06-09
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Portable Temperature/Humidity Data Loggers with Display
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Portable Temperature/Humidity Data Loggers with Display
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