Fluke Calibration 1620A Precision Thermo-Hygrometer

Fluke Calibration 1620A Precision Thermo-Hygrometer is rated 2.3 out of 5 by 3.
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  • Fluke Calibration 1620A Precision Thermo-Hygrometer
  • Fluke Calibration 1620A Precision Thermo-Hygrometer

Key features

The most accurate temperature and humidity graphical data loggers on the market

The DewK measures temperature to ±0.125 °C and humidity to ±1.5% on two channels, and displays it on a big, clear screen. Ethernet, wireless (optional), or RS-232 will allow you to network as many DewKs as you’d like. And the Log Ware III software will allow real-time logging of multiple DewKs, data storage to your computer and seamless integration with MET/CAL® software.

  • Superior accuracy
  • Network enabled
  • Powerful logging and analysis tools
  • Two interchangeable calibrated sensors
  • Huge memory
  • Upgraded software

Product overview: Fluke Calibration 1620A Precision Thermo-Hygrometer


The standard-accuracy sensor (“S” model) reads temperature to ±0.25 °C over its calibrated range of 15 °C to 35 °C. Relative humidity readings are to ±2% RH from 20% RH to 70% RH.

All DewK sensors come with NVLAP accredited certificates of calibration for both temperature and humidity, complete with data and NIST traceability.

Ethernet and wireless capability

With its built-in Ethernet RJ45 jack, multiple DewKs can be monitored from the same screen using Log Ware III client-server software. Ethernet also gives you the possibility for remote connectivity over the internet, so you can monitor critical conditions while you’re away.

Cables running along the floor can be a safety hazard, and cables hanging from the ceiling and walls are an eyesore. With the DewK, simply connect your computer through an RF modem up to 100 ft away, without the clutter of all the extra cables.

If you need a printout, send data to a printer through the RS-232 interface in real time.

Math and statistical functions

In addition to temperature and humidity, the DewK calculates dew point, heat index, and rates of change for both temperature and humidity. Min, max, and a variety of other statistics are also calculated and can be shown on-screen. Daily summary statistics, including min, max, and maximum rates of change are stored for the most recent sixty days.

Calibrated sensors

With inputs for two sensors, each measuring both temperature and relative humidity, one DewK can monitor two locations at the same time. Both sensors can be run via extension cables to remote locations up to 100 feet away, or one sensor can be directly mounted to the top of the DewK.

Each sensor is calibrated for both temperature and humidity by Fluke Calibration. The calibration constants assigned to the sensors reside in a memory chip located inside the sensor housing, so sensors may be used interchangeably between different DewKs, and the recalibration of sensors doesn’t require an accompanying DewK.

Sensors may also be assigned a unique identifier (up to 16 characters) to facilitate record keeping by matching the sensor identifier with the collected data. Each DewK ships with one sensor, with additional sensors available directly from your local Fluke Calibration sales representative, or directly from Fluke Calibration. Spare sensors may also be purchased from Fluke Calibration as a kit, which includes a case for the sensor, a wall mounting bracket, and a 25-foot extension cable.


The DewK has enough on-board memory to store up to 400,000 date- and times stamped data points. That’s two years' worth of data for both measurements from two sensors if readings are taken every ten minutes!

Alarms and battery backup

Alarm settings can be set up quickly in the DewK based on temperature, the rate of change in temperature, RH, the rate of change in RH, and instrument fault conditions. Alarms can be both visual (flashing display) and audible (beeping). Likewise, alarm settings can be set up and events triggered in Log Ware III. The DewK is also equipped with a 0 to 12 volt alarm output that can trigger a process control system.

A backup battery shuts down the DewK’s display but maintains measurements for up to 16 hours in the event of a power failure.

Large, easy-to-read display

Want to view data from across the room? Want to view data from two temperature and two humidity inputs simultaneously? Want to view data graphically, statistically, or both? At the same time?! The DewK does everything you could want—or at least everything we could think of. Up to sixteen different display setups can be stored and recalled at the touch of a single button. And all 16 can be easily modified, so you get exactly what you want.

Specifications: Fluke Calibration 1620A Precision Thermo-Hygrometer

Operating range0°C to 50°C (32°F to 122°F); 0% RH to 100% RH
Calibrated temperature Accuracy±0.25°C from 15°C to 35°C
(±0.45°F from 59°F to 95°F)
Calibrated RH accuracy±2% RH from 20% RH to 70% RH
Expected extrapolated performance (uncertified)±0.5°C (±0.9°F) outside calibrated range
±3% RH outside calibrated range
Delta temperature accuracy±0.025°C for ±1° changes within 15°C to 35°C
(±0.045°F for ±1° changes within 59°F to 95°F)
Temperature resolutionUser selectable up to 0.001°C/°F on front-panel display (0.01° recorded)
Delta humidity accuracy±1.0% RH for ±5% changes within 20% RH to 70% RH
RH resolutionUser selectable up to 0.01% on front-panel display (0.1% recorded)
InputsUp to two sensors, measure temperature and relative humidity, detachable, cable-extendable, interchangeable, self-contained calibrations, may be assigned unique 16-character identifications
Display240 x 128 graphics monochrome LCD, displays password-protected temperature/humidity data graphically, numerically, and statistically (one or both channels); 16 pre-defined, user-changeable screen setups
Memory400,000 typical individual date/time-stamped readings
AlarmsPassword-protected visual, audible, and external alarms for temperature, temperature rate, RH, RH rate, and fault conditions
Alarm port output2.5 mm two-conductor subminiature plug, 0 V normal, 11 to 12 V active, sources up to 20 mA
ConnectivityEthernet, RS-232, RF (optional)
EthernetRJ45 jack, 10 Base-T or 100 Base-TX; static or dynamic (DHCP client) IP address assignment
Web pageEmbedded web page interface features: instrument identification, measurements, password-protected terminal page; can be disabled
Wireless optionRequires wireless modem. 802.15.4 (underlies Zigbee), 2.4 GHz frequency, 1 mW transmit power, 30 m (100 ft) typical unobstructed range; can be disabled
MountingWall mounted (hardware included) or set on a bench top
Power12 V DC from external 100 to 240 V DC power supply
Battery backupStandard 9 V battery enables continued measuring during power disruptions
Size (DewK) (H x W x D)125 x 211 x 51 mm (4.9 x 8.3 x 2.0 in)
Size (sensors) (L x Dia)79 x 19 mm (3.1 x 0.75 in)
Weight0.7 kg (1.5 lb)
CalibrationCertificate of NIST-traceable NVLAP accredited temperature and humidity calibration included; As Found and As Left data supplied at three temperature points and three humidity points each at 20°C (68°F); Complies with NCSL/ISO/IEC 17025:2000 and ANSI/NCSL Z540-1-1994
LogWare III (optional software)Requirements include: Microsoft® Windows® 2000 (SP4) or XP (SP2) operating system, IBM compatible Intel Pentium® IV 1 GHz PC processor or better, 512 Mb RAM (1 Gb or more recommended), 200 Mb HDD space for installation (additional free space recommended for data storage), CD-ROM drive for installation

Models: Fluke Calibration 1620A Precision Thermo-Hygrometer

Fluke 1620A-S

Fluke Calibration 1620A-S-156 Precision Thermo-Hygrometer
Standard Accuracy

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  • One standard-accuracy sensor
  • Wall mount bracket
  • RS-232 cable
Fluke 1620A-H
Fluke Calibration 1620A-H Precision Thermo-Hygrometer
High Accuracy
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  • One standard-accuracy sensor
  • Wall mount bracket
  • RS-232 cable
Fluke 1621A-S
Fluke Calibration 1621A-S Precision Thermo-Hygrometer
Standard Accuracy Value Kit with spare sensor and software
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  • 1620A-S Thermo-Hygrometer, Standard-Accuracy
  • 2627-S Spare Sensor Kit
  • 9936A LogWare III Software, Single License
Fluke 1621A-H
Fluke Calibration 1621A-H Precision Thermo-Hygrometer
High Accuracy Value Kit with spare sensor and software
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  • 1620A-H Thermo-Hygrometer, High-Accuracy
  • 2627-H Spare Sensor Kit
  • 9936A LogWare III single-PC license (required for use with MET/CAL software)
Fluke 1622A-S

Fluke Calibration 1622A-S Precision Thermo-Hygrometer

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  • 1621A-S Value Kit
  • 2633-RF Wireless Option (requires wireless modem)
  • Wireless Modem, USB to wireless
LogWare III SoftWare, Single License
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Additional 1-Pack License for LogWare III SoftWare
(Additional licenses require the purchase and installation of 9936A LogWare III Software (single license))
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Additional 5-Pack Licenses for LogWare III SoftWare
(Additional licenses require the purchase and installation of 9936A LogWare III Software (single license))
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Additional 10-Pack Licenses for LogWare III SoftWare
(Additional licenses require the purchase and installation of 9936A LogWare III Software (single license))
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Additional Site License for LogWare III SoftWare
(Additional licenses require the purchase and installation of 9936A LogWare III Software (single license))
Buy it
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Rated 1 out of 5 by from Software We have these units in our laboratory. The software that is within these units is not intuitive. It is very difficult and frustrating trying to set-up measurement parameters and the information that Fluke provides with these units is severely lacking in any proper information to adequately set these units up. You end up trying to navigate through its menu and deciphering what all the acrononsense it is displaying without any guidance from the accompanying documentation. Truly a MAJOR WASTE OF TIME! If they could provide clear and concise instructions on properly setting these units up it would be a major step forward
Date published: 2017-01-09
Rated 2 out of 5 by from Not compatible with Java 8 Its inability to work with Java 8 is very disappointing, inefficient, and inconvenient for my calibration lab. It is a shame that the development team for this product has yet to make the 1620A compatible with Java 8, which at the time of this email is on its 66th update. I hate that my company purchased a product that is seemingly no longer supported, especially considering that this product is still a current model. What angers me is that there is no indication anywhere in the documentation or on the product webpage stating that the remote monitoring feature is useless. I use the term “useless” without any qualification because Java has removed version 7 from its website as of July of 2015, so it is no longer possible to revert back to version 7 to use the 1620A webpage functionality. My lab (one of 26 in our network) is (was) the test bed for this system’s capabilities, especially concerning the ability to remotely monitor the environment. I have four technicians with their own work benches in two separate rooms that were supposed to be able to pull the data they need at their workstations. Now they will have to waste time to go view the display directly. Not only that, as the manager, I will have to remove the display from its mount, bring it into my office, connect it to my computer (after purchasing and configuring a serial to USB adapter, of course), and use hyperterminal to download the data on a weekly basis. There are other much larger labs in my metrology network that were hoping to use this system (read: purchasing one or two 1620As and up to 6 probes per lab), but once they learn of the lack of engineering support to develop an upgrade to be compatible with Java 8, they will be looking for other suppliers that keep their hardware up to date. In the meantime, I will also be shopping for alternative manufacturers who actually support the functionality that is clearly listed in their products’ descriptions. There are other, less expensive alternatives available on the market that support remote monitoring with comparable accuracy to the 1620A.
Date published: 2016-01-12
Rated 4 out of 5 by from Fluke 1620a High Accuracy Our lab uses (3) meters and (6) High accuracy temperature/humidity sensors.. We use the command set to pull temperature and humidity values from the loggers and incorporate into our own applications. This works the best. We have never had any problems. Other test equipment in our lab requires the use of the DEWKs web page interface to readout the values. However, the firmware in the DEWK uses an obsolete version of JAVA. Hopefully it will be updated soon. Thus I am only rating it as good with 4 stars.. If the firmware was updated to work with current versions of JAVA... i would give it a total of 5 stars.
Date published: 2015-11-06
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