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
  • Saturation intensities include the standard 3,500 μmoles OJIP intensity, as well as: 3,000 μmols, 525 μmols ,875 μmols, 1,000 μmols, 2,500 μmols, 4,500 μmols, & 6,000 μmols.
  • 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 - data files and graph data open directly into Excel ®
  • Housekeeping automation reduces set up time and eliminates some types of measuring errors.
  • A light bar aides in modulated light intensity set up, using a red modulated light.
  • 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:

    600- 6000 μmols set from 10% to 100%

    Saturation light source:

    Array of red LEDs 660 nm.

    Modulated light source:

    Red 0.2 to 1.0 μmols.

    Detection method:

    Pulse modulated

    Detector and Filter:

    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; however, the software takes a rolling eight point 25 ms average to determine FO, and FM, making it idea for both algae and land plants.

    Modulated light adjustment:

    Manual adjustment from 30% to 80%

    Parameters measured and graphed:

    FO, FM, FV/FM, FV/FO

    JIP Test


    Actinic light intensities:

    6000 μmols, 4500 μmols, 3500 μmols, 3000 μmols, 2500 μmols, 1000 μmols, 875 μmols, 525 μmols. An array of red LEDs at 650 nm are used for actinic illumination.

    Detection method:

    Pin photodiode detector with 700-750 nm band pass filter using red pulse modulated light, and variable sampling rate from 10μs to seconds.

    Test duration:

    JIP test 3 - 300 seconds

    JIP Test parameters measured:

    Direct readout parameters: O, t100μs, t300μs (or K), t2ms (or J), t30ms (or I), P, tFM, A (area above the curve), MO (or RC/ABS), PIABS (or performance index) FO, FM, FV/FM, FV/FO. Up to 32 OJIP traces can be overlaid and displayed on the graphic display screen, Colors on the screen start to repeat after 16 traces. FO is measured not estimated.

    Measured parameters reported to the data file: ABS/RC, TRO/RC, DIO/CS, ETO/RC, TRO/ABS, ETO/TRO, ETO/CS, RC/CSO, RC/CSM, S, M, T are also measured and recorded in the data file, but not on the measuring screen.

    Up to 32 traces can be overlaid on the graphic display screen, and up to 32 traces, per file name, can be stored for graphic overlay of traces in a single data file. Colors start to repeat on the viewing screen after 16 traces are overlaid. This limitation does not exist in the data file. If traces are not stored, thousands of measurement parameter sets can be stored in a single data file for spider graphing. The number of data files are only limited by machine memory limits.




    Color Graphic Display

    Storage Capacity:

    Up to 160,000 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 port


    NiMH battery pack with a battery life of 8 hours between charges.


    18 cm, 7 cm, 6 cm.


    1.25 lbs., with carrying case and accessories - 4 lbs.

    Carrying case:


    Case dimensions: 36 cm, 28 cm, 15 cm.

  • 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