Professional Plus

Manufacturer: YSI
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The YSI Professional Plus handheld multiparameter meter provides extreme flexibility for the measurement of a variety of combinations for dissolved oxygen, conductivity, specific conductance, salinity, resistivity, total dissolved solids (TDS), pH, ORP, pH/ORP combination, ammonium (ammonia), nitrate, chloride and temperature. Also a very powerful lab instrument for BODs, pH and ORP.

The Quatro cable attached to the Pro Plus allows you to utilize 4 ports to measure temperature/conductivity, DO, and any two ISEs among pH, ORP, ammonium, chloride, or nitrate creating an extremely powerful handheld multiparameter instrument.

Key Features

  • Easy-to-install cable weights; can be daisy-chained for additional weight
  • Rubber, over-molded IP-67 waterproof case (even without the battery cover)
  • Rugged cables, sensors, and military-spec connectors
  • Drop-tested 1 meter at all angles
  • Scratch-resistant lens; viewable with polarized glasses
  • Instrument floats
  • Weighted, user-replaceable multi-sensor design
  • 5,000 data set memory
  • Detailed on-screen Help function
  • Free, Data Manager desktop software and ProComm II saddle
  • Interval or single-event logging
  • 100 folder & site list data structure
  • Password protection
  • Detailed GLP data
  • USB connection also powers the instrument
  • 6-point cal with auto-buffer recognition
  • User-adjustable auto-stable with prompts
  • User-upgradeable software via waterproof USB port
  • Recalibration prompts
  • Search function filters user-defined data information
  • Backlit display and keypad
  • Cable management kit included with all cables from 4 to 30 meters
  • Adjustable right- or left-handed hand strap
  • Multiple user-replaceable sensor options and a choice of DO sensors
  • Multiple parameter options and cable lengths
  • Lab-grade ISE sensors and BOD probe available to make a true lab/field instrument
  • Languages - English, Spanish, German, French, Italian, Norwegian, Portuguese, Japanese, Chinese (Simplified and Traditional)
  • Wide array of accessories are available from flow cells, to shoulder straps, to carrying cases

Auto Stable

  • User-defined auto-stable function holds stable readings on display when criteria is met


  • Built-in barometer

Buffer Recognition

  • Auto buffer recognition for US and NIST buffers


  • RoHS
  • CE
  • WEEE
  • C-Tick
  • VCCI
  • FCC
  • IP-67
  • 1-meter drop test


  • USB 2.0
  • ProComm II communications saddle and USB cable included
  • User-upgradeable software via USB and website


  • MS (military spec) waterproof with bayonet lock

Data Management

  • Data Manager desktop software included
  • 100 user-defined folders and site names
  • Minimum PC requirements
    • •Windows 2000 with SP4 (minimum) or XP with SP2 (minimum)
    • 300 MHz or higher Pentium-compatible CPU
    • 128 MB of RAM or higher
    • 80 MB or more of free hard-disk space
    • USB 2.0
    • Microsoft.NET (installed with Data Manager)

Data Memory

  • 5,000 data sets (data, date, time, user-defined info)
  • 100 GLP files


  • 8.3 cm width x 21.6 cm length x 5.6 cm depth (3.25" x 8.5" x 2.21")


  • Graphic display with detailed Help; backlit display and keypad

DO Membrane Response Times (T95; 100%-0) and Flow Dependence

  • 1.25 mil PE = 8 seconds and 6 in/sec flow
  • 2.0 mil PE = 17 seconds and 3 in/sec flow
  • 1 mil Tefl on® = 18 seconds and 12 in/sec flow

DO Sensors

  • Polarographic or galvanic field sensors
  • Self-stirring polarographic BOD sensor for the lab

Field Cables

  • Standard lengths of 1, 4, 10, 20, or 30 meters - up to 100 meters on DO only cables
  • 4- through 30-meter cables include a cable management kit

Flow Cell

  • Single, dual and multiparameter Quatro cable all flow cell compatible

GLP Compliance

  • Yes
  • Detailed GLP information is stored and is available to view, download or print

Lab Cables

  • BOD sensor includes 2-meter cable; 1 or 4 meters on lab pH, ORP and pH/ORP cables


  • English, Spanish, German, French, Italian, Norwegian, Portuguese, Japanese, Chinese (Simplified & Traditional)

Logging Modes

  • Single or Continuous

Operating Temperature

  • -10 to 60° C


  • 2 alkaline C cells provide 80 continuous hours at ambient temperature without backlight
  • ProComm II saddle provides USB power or optional wall power, cigarette lighter, and universal cell phone charger options

Storage Temperature

  • -20 to 70° C

User ID

  • Optional user ID for data security


  • IP-67 (even with the battery cover off)
  • Floats

Weight with Batteries

  • 475 grams (1.05 lbs)