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Advanced Conductivity Benchtop Meter - HI6321

HI6321 is a streamlined Conductivity/Resistivity/TDS/Salinity/Temperature benchtop meter with a large touch screen display, comprised of a housing and an integrated conductivity measurement module.


HI6321 is a streamlined Conductivity/Resistivity/TDS/Salinity/Temperature benchtop meter with a large touch screen display, comprised of a housing and an integrated conductivity measurement module.

Compact and easy to operate, the HI6321 includes Hanna’s HI7631233 four-ring conductivity/ resistivity/TDS/salinity probe.

Recommended for a wide range of industrial process water applications, HI7631233 provides stable measurements over a wide measurement range and does not require frequent calibrations. An integral temperature sensor measures the process temperature and adjusts the measured conductivity to a reference temperature by applying specialized compensation algorithms:

  • Linear: appropriate when it is assumed that the temperature coefficient of variation has the same value for all measurement temperatures.
  • Standard: appropriate for high-purity water measurements and documented in ASTM Standard D5391-14. This setting should be used for >1Mohm.cm resistivity measurements.
  • Natural: appropriate for natural ground, well, or surface water (or water with similar composition) in accordance with ISO7888 standard.

The result is reliable electrolytic conductivity (EC), TDS (Total Dissolved Solids), resistivity, or Seawater Salinity in percent, psu, or ppt units.

TDS is a calculated value based on the conductivity of the solution (TDS = factor x EC25). A TDS factor is a conversion factor used to change an EC measurement to a ppm measurement.

Sal psu: The practical salinity of seawater relates the ratio of electrical conductivity of a normal seawater sample at 15 ℃ and 1 atmosphere to a potassium chloride solution (KCl) with a mass of 32.4356 g/Kg water at the same temperature and pressure. Under these conditions the ratio is equal to 1 and S=35. The practical salinity scale may be applied to values 0 through 42.00 psu at temperatures between 0 to 35 ℃.

Sal ppt: measurements expressed in ppt are based on the Natural Seawater Scale that extends from 0.00 to 80.00 g/L and covers 10 to 31 ℃ temperature range. It determines the salinity based upon a conductivity ratio of sample to standard seawater at 15 ℃ and an approximate salinity value of 35 in seawater.

Sal %: in this scale 100% salinity is equivalent to roughly 10% solids.

User interface

  • 7-inch capacitive touch screen with multi-touch support
  • Capacitive touch back, home and system menu keys
  • User-friendly icons and symbols allow users to easily navigate and interpret the instrument functions.

The user can select between five different views:

  • Basic measurement configuration
  • Simple GLP with calibration information
  • Full GLP with electrode status and calibration point details
  • Live updated, interactive graph
  • Tabulated data with date, time, and notes


  • Measure µS/cm, mS/cm (Conductivity); ω·cm, kω·cm, Mω·cm (Resistivity); ppm, ppt (TDS); ppt, PSU,
    % (Salinity) with temperature
  • Application-specific profiles allow quick and direct measurement without the need to update the sensor
    and system settings
  • Active log during measurement o Measurement stability indicator (using the Stability Criteria setting)
  • Reading modes: direct and direct/autohold
  • Temperature compensation can be Automatic or set manually
  • Audible and/or alarm messages for measurements outside of predefined limits
  • Galvanic isolation for conductivity measurement


  • Standard single point salinity calibration in 100% salinity standard, with the reading salinity scale set to %
  • Standard single or multiple conductivity calibration with standards
  • Non-volatile memory saves data and settings


  • Data log collection of at least 1, 000, 000 data points (with time and date stamp)
  • Logging types: manual, automatic, autohold
  • Sample ID for manual and Autohold data

Connectivity features & services

  • Transfer logged data to a USB thumb drive
  • Log files that include measurements and calibration data (as .csv file)
  • FTP and email for log export via Ethernet and Wi-Fi connection o USB type A for USB stick,
    keyboard, and printer
  • USB type C for USB stick and PC connection

Additional information

Weight 1.2 kg

Conductivity/TDS, Salinity, Temperature


SKU HI6321
Name Advanced Conductivity Benchtop Meter – HI6321
Conductivity Range 0.000 to 9.999 µS/cm; 10.00 to 99.99 µS/cm; 100.0 to 999.9 µS/cm; 1.000 to 9.999 mS/cm; 10.00 to 99.99 mS/cm; 100.0 to 1000.0 mS/cm
Conductivity Resolution 0.001 µS/cm; 0.01 µS/cm; 0.1 µS/cm; 0.001 mS/cm; 0.01 mS/cm; 0.1 mS/cm
Conductivity Accuracy ±1 % of reading (±0.01 µS/cm)
Resistivity Range 1.0 to 99.9 Ω·cm; 100 to 999 Ω·cm; 1.00 to 9.99 KΩ·cm; 10.0 to 99.9 KΩ·cm; 100 to 999 KΩ·cm; 1.00 to 9.99 MΩ·cm; 10.0 to 100.0 MΩ·cm
Resistivity Resolution 0.1 Ω·cm; 1 Ω·cm; 0.01 KΩ·cm; 0.1 KΩ·cm; 1 KΩ·cm; 0.01 MΩ·cm; 0.1 MΩ·cm
Resistivity Accuracy ±1 % of reading (±1 Ω·cm)
Total Dissolved Solids (TDS) Range 0.000 to 9.999 ppm; 10.00 to 99.99 ppm; 100.0 to 999.9 ppm; 1.000 to 9.999 ppt; 10.00 to 99.99 ppt; 100.0 to 400.0 ppt; actual TDS (with 1.00 factor)
Total Dissolved Solids (TDS) Resolution 0.001 ppm; 0.01 ppm; 0.1 ppm; 0.001 ppt; 0.01 ppt; 0.1 ppt
Total Dissolved Solids (TDS) Accuracy ±1 % of reading (±0.01 ppm)
Salinity Range 0.00 to 42.00 PSU – Practical Scale 0.00 to 80.00 ppt – Natural Sea Water 0.0 to 400.0 % – Percent Scale
Salinity Resolution 0.01 for Practical Scale / Natural Sea Water 0.1 % for Percent Scale
Salinity Accuracy ±1 % of reading
Temperature Range −20.0 to 120.0 °C −4.0 to 248.0 °F 253.0 to 393.0 K
Temperature Resolution 0.1 °C; 0.1 °F; 0.1 K
Temperature Accuracy ±0.2 °C; ±0.4 °F; ±0.2 K
Conductivity Calibration points Auto standard recognition / User standard, Single Point / Multi Point calibration
Conductivity Calibration Standard solutions 84.00 µS/cm, 1.413 mS/cm, 5.000 mS/cm, 12.88 mS/cm, 80.00 mS/cm, 111.8 mS/cm
Conductivity Calibration Reminder Disabled Daily: 0 m in. to 23 hours and 59 m in. Periodic: 1 m in. to 500 days, 23 hours and 59 m in.
Salinity Calibration 1 point for Percent Scale
Temperature Compensation Automatic or Manual
Reading Modes Direct Direct/Autohold
Reading Stability criteria Accurate Medium Fast
Reading Sampling rate 1000 ms
EC Views Basic Measurement (EC, Resistivity, TDS, Salinity, Temperature) Stability status
EC Views Simple GLP Basic view information Last calibration date, offset
EC Views Full GLP Simple GLP information and calibration point details
EC Views Table Measurements updated every second are displayed in table
EC Views Graph (Plot) Measurement versus time graph can be panned or zoomed (pinch-to-zoom technology)
Logging Type Automatic, Manual, Autohold
Logging Number of records 50 000 maximum per file Stores at least 1 000 000 data points per user
Logging Automatic interval 1, 2, 5, 10, 30 seconds 1, 2, 5, 10, 15, 30, 60, 120, 150, 180 minutes
Logging Sample ID Incremental mode
Logging Export option .csv file format
Users Up to 9 users and the default administrator account
Connectivity USB-A 2 ports for keyboard input or USB thumb drive
Connectivity USB-C 1 port for PC connectivity and USB-C type thumb drive
Connectivity Wi-Fi & Ethernet FTP Web server Log transfer and download Email
Connectivity RS232 Connecting peripherals
Power supply DC adapter 100-240AC to 24VDC 2.5A
Environment 0 – 50 °C / 32 – 122 °F / 273 – 323 K maximum 95% RH non-condensing
Dimensions 205 x 160 x 77 mm (8.0 x 6.2 x 3.0 “)
Weight Approximately 1.2 kg (26.5 lbs.)


Advanced Conductivity Benchtop Meter – HI6321