The Standard in

Plant Stress Measurement



Provides the best of both worlds - FV/FM & calibrated Strasser OJIP measurements

The OS30p+ provides a graphic color display of both FV/FM protocol measurements & Strasser OJIP protocol measurements. FV/FM is the most used chlorophyll fluorescence measuring protocol in the world and the OS30p+ makes this and Strasser OJIP very affordable, in part, by elimination of an expensive fiber-optic light guide and the introduction of a short, dark clip friendly, optical probe.


  • Direct readout and graphic display of FV/FM and FV/FO measurements
  • Self calibrating red Strasser OJIP light source  at 3,500 μmoles -  Because Strasser OJIP values change with actinic light intensity. 3,500 μmoles are recommended.
  • Color graphic screen - allows multiple overlayed Strasser color graphs
  • Direct readout of the most used Strasser protocol parameters including: O, t100, K, J, I, P, tFM, PIABS, Vj, MO, & A
  • Print out of all of Strasser's measuring parameters in the data file.
  • Easy modulated light intensity set up with helpful intensity bar.
  • Affordable dark adaptation clips
  • USB port for easy data transfer
  • Housekeeping automation reduces set up time and eliminates some types of measuring errors.
  • Signal bar aides in modulated light intensity set up.
  • Automated 8 point 25ms rolling average to determine maximum FM. This eliminates saturation pulse NPQ as a source of error if the saturation pulse is too long. This feature is only used in the FV/FM protocol.
  • Automatic light calibration to 3,500 μmols.
  • The OS30p+ is a modulated fluorometer with a calibrated red actinic LED light source designed to provide optimal measurement of both FV/FM and Strasser protocol OJIP  parameters. The instrument provides a graphic display for the FV/FM protocol and a color overlay display of OJIP graphs. Direct readout is available for FO, FM, FV/FM, & FV/FO. Direct readout is also available for the most used Strasser OJIP protocol parameters, including: PIABS, Vj, Mo, Area above the curve, O, t100, K,  J, I, P, & tFM . All of the Strasser OJIP protocol parameters are reported & arranged in the data file for easy spider graphing and trace overlay graphing. Output is by USB port.

  • FV/FM, FV/FO Test


    Saturation intensity:

    Adjustable from 600 - 6,000 μmols.

    Saturation light source:

    Array of 660nm red LEDs.

    Modulated light source:

    Adjustable from 0.1 to 0.6 μmols.

    Detection method:

    Pulse modulated using a PIN photodiode with 700-750 nm band pass filter.

    Test duration:

    0.1 seconds to 1.5 seconds. The default saturation pulse duration is set at 1.0 second. Software takes a rolling eight point average to determine FO, and FM, making it idea for both algae and land plants.

    Parameters measured:

    FO, FM, FV/FM, FV/FO, graphical display of trace.

    Strasser OJIP Test


    Actinic illumination:

    An array of 650 nm red LEDs adjustable up to 6,000 μmols.

    Detection method:

    Pin photodiode detector with 700-750 nm band pass filter. Variable sampling rate based on test phase.

    Test duration:

    3 - 300 seconds.

    Test parameters measured:

    Direct readout parameters:
    O, t100μs, t300μs (K), t2ms (J), t30ms (I), P, tFM, A (area above the curve), MO (RC/ABS), PIABS (performance index) FO, FM, FV/FM, FV/FO. FO is measured not estimated.

    Additional recorded parameters:

    Up to 32 traces can be overlaid on the graphic display screen, and up to 32 traces per file name can be stored. Colors start to repeat on the viewing screen after 16 traces are overlaid. If traces are not stored, thousands of measurement parameter sets can be stored in a single data file for spider graphing.




    Color Graphic Display.

    Storage Capacity:

    Greater than 100,000 measurements. Up to 32 traces can be stored with one data file name. Hundreds of traces can be stored in multiple data files, with different names.

    Digital output:

    USB removable storage device standard. Comma delimited files.


    NiMH battery pack. Runtime of 8 hours between charges.


    20 X 10 X 8 cm (13 x 10.5 x 6 inches).


    0.6kg (1.25 lbs).

    Hard shell transport case:

    33 X 27 X 15 cm (13 x 10.5 x 6 inches).
    2.0kG (4.3 lbs) with instrument and accessories.

    Specifications subject to change without notice.

  • FL-DC

    Dark adaptation clip


    Pouch of 50 clips

  • PDF document.

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Opti-Sciences, Inc.     8 Winn Avenue      Hudson NH 03051       USA      (603)883-4400

Opti-Sciences, Inc.

8 Winn Ave

Hudson, NH 03051, USA

Phone: (603) 883-4400

Fax: (603) 883-4410