
Portable Data Loggers with Display 
Part of the NOMAD® Family
OM-73, temperature/relative 
humidity data logger.
OM-70 Series
FREE Thermocouple Included!
Model OM-74 Includes a free 1 m (40”) Type K insulated  
beaded wire thermocouple with subminiature connector and wire spool 
Optional
caddy. Order a Spare! Model No. SC-GG-K-30-36.
OM-74, 
thermocouple 
data logger.
OM-71, 
data logger
temperature 
.
OM-72, 
temperature 
data logger 
with remote 
sensor.
U LCD Real Time Display of 
Temperature (°C or °F), Relative 
Humidity (% RH, Model OM-73 
Only), Time, Date, Alarm Status, 
Recording Status and 
Battery Condition
U User Selectable Stop on 
Memory Full or Memory 
Rollover for Continuous 
Recording
U PC Delayed Start or Push-
Button Recording Control 
U Read Recorded Data 
on Logger Display
U Displays Alarm Icon for High/
Low Alarm Conditions
U Nonvolatile EEPROM 
Memory Retains Data  
Even if Battery Fails
U USB Interface for Fast 
Data Transfer
U Compact, Light Weight, 
Easy-to-Use
The OM-70 Series of portable 
temperature and temperature/ 
humidity data loggers are easy-touse, 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. Easyto-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 magnies data with powerful 
 zoom and autoscale functions.
• Autoscale function ts 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 conguration 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.
To Order, Call  or Shop Online at omega.com
SM
1

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.
Specifications 
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
Relative Humidity Resolution 
(Model OM-73): 0.05% RH
OM-74 
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 Ω 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) 
GENERAL 
Sample Rate: 1 second 
to 18 hours user selectable
SM
Extended Warranty
Program
OMEGACARESM extended warranty program 
is available for models shown on this page. 
Ask your sales respresentative for full details 
when placing an order. OMEGACARESM 
covers parts, labor and equivalent loaners.
Thermocouple Temperature Range and Accuracy (OM-74)
 Thermocouple   Accuracy1  Logger Supported Range
 K  ±0.7°C (1.3°F)  -250 to 1300°C (-418 to 2372°F) 
 J  ±0.6°C (1.0°F)  -170 to 1000°C (-274 to 1832°F) 
  E  ±0.4°C (0.8°F)  -200 to 820°C (-328 to 1508°F)
  N  ±0.8°C (1.5°F)  -200 to 1300°C (-328 to 2372°F) 
  T  ±0.7°C (1.3°F)  -200 to 400°C (-328 to 752°F) 
 S  ±2.8°C (5.0°F)  -50 to 1760°C (-58 to 3200°F) 
  R  ±2.8°C (5.0°F)  -50 to 1760°C (-58 to 3200°F) 
  B  ±3.3°C (6.0°F)  20 to 1820°C (68 to 3308°F) 
  C  ±1.7°C (3.0°F)  0 to 2320°C (32 to 4208°F)
1
The accuracy given is for the OM-74 unit only. Errors may increase depending on the 
thermocouple wire grade used. 
The logger can only display temperatures up to 1999°F or 1999°C
2
The logger supported range is for stored temperature. 
Alarm Settings:  
Over/under alarm  
with visual indication
Windows software 
displays data 
in graphical or 
tabular format.
2
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; 
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 
(32- and 64-bit)
To Order 
 Model No.  Description
 OM-71  Temperature data logger with display  
 OM-72 
 OM-73  Temperature/humidity data logger with display
 OM-74  Thermocouple data logger with display 
 OM-74-NIST 
 OM-71-NIST 
 OM-72-NIST 
OM-40-BATT-6 Replacement 3V lithium battery (box of 6), for OM-71, OM-72 and OM73
 CAL-3-HU  NIST traceable calibration certificate for OM-73
Comes complete with Windows software, operator’s manual on CD, USB interface cable 
and battery.
Ordering Example: OM-73, temperature/humidity data logger with display and OCW-1 
OMEGACARE 1 year extended warranty adds 1 year to standard 1 year warranty.
Visit omega.com/om-70_series for Pricing and Details
43,344 
Interface: USB 2.0 
Power: OM-71, OM-72, OM-73:
3V CR2032 lithium  
battery (included); 
OM-74: 3 AAA batteries (alkaline  
or lithium (included)
Battery Life: 3 years (average) 
Dimensions:  
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")
Weight: OM-71, OM-72, OM-73: 
91 g (3.2 oz) 
OM-74: 62 g (2.2 oz)
Temperature data logger with display and remote temperature sensor 
Thermocouple data logger with display and NIST calibration certificate 
Thermocouple data logger with display and NIST calibration certificate 
Thermocouple data logger with display and remote temperature sensor 
and NIST calibration certificate
2
To Order, Call  or Shop Online at omega.com
SM