FMS 2 -Field Portable Pulse Modulated Chlorophyll Fluorometer

  • Pulse-modulated system
  • Compact Field Design
  • Temperature Compensated Electronics
  • Programmable by Hansatech Scripting Language (HSL)
  • Leaf-clip with integral PAR/temperature sensor
  • Field Swappable Battery System
  • Windows® data acquisition & data analysis software


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  • The FMS 2 chlorophyll fluorometer consists of a control unit housing all of the electronics, optics and light sources necessary to derive most common chlorophyll fluorescence parameters. These are optically linked to the sample by a statistically randomised fibre optic cable that is positioned in the FMS/PTL PAR/Temperature leafclip. The fibre optic cable is also suitable for insertion into a range of sample containers such as oxygen electrodes,gas analysis chambers, petri dishes and microtitre plates.
  • The system may be operated in several different modes: serial connection to a Windows® PC enables real-time instrument control and data presentation. Captured data is simultaneously presented as a real-time chart recorder emulation and parameters-only format for easy identification of key experimental events. This PC mode of operation is suitable for development of complex protocols which may be programmed into the instrument using the simple drag and drop editor to generate user-defined scripts. These scripts automate the execution of experiments in the field, allowing complex protocols involving many control events to be operated with the same ease as single control event measurement such as Fv/Fm. Once programmed, the FMS 2 can be used as a stand-alone chlorophyll fluorometer in either laboratory or field situations, running from internal batteries with all measurement data and calculated parameters saved to integral protected memory. The unit can store up to six experimental protocols, any one of which may be accessed and executed using the built-in menu system. When data collection is complete the results can be downloaded to the Windows® software for full analysis.
  • All of the light sources required for modulated measurement of common chlorophyll fluorescence parameters are self-contained within the instrument.
  1. 594 nm amber modulating beam with 4 step frequency control. (Optional470 nm blue LED)
  2. Dual-purpose halogen light source providing actinic light (0 – 3000 µmol m-2 s-1 in 50 steps)   and saturating pulse (0 – 20,000 µmol m-2 s-1 in 100 steps)
  3. 735 nm far-red LED source for preferential PSI excitation allowing accurate determination of the Fo’ parameter

FMS/PTL PAR/Temperature Leafclip


  • The PAR / temperature leafclip is available to facilitate measurements made under ambient light conditions using the FMS 2 chlorophyll fluorometer. Chlorophyll fluorescence measurements can be made quite satisfactorily without the leafclip but a value of PAR from the light sensor on the leafclip is essential for the estimation of electron transport rate by the FMS software. Other chlorophyll fluorescence parameters are unaffected if the system is operated without the leafclip.
  • The FMS/PTL leafclip consists of a sprung upper section which gently grips the sample in a gentle clamping action. A grooved neck mounted at 60° to the plane of the sample accommodates the fibre optic cable which is slid into position.
  • Marked graduations on the neck can be aligned with graduations on the fibre optic cable termination to reference its position for future work, a retaining screw locks it into position throughout the experiment. The rest of the fibre optic cable may be looped over the leafclip and hooked to the rear of the clip to help support its weight. A fully cosine corrected PAR sensor and 0 – 90°C thermocouple are also fitted to the FMS/PTL.
  • An electrical connection to the Leafclip socket on the front panel of the FMS 2 chlorophyll fluorometer enables use of the remote trigger switch to activate / abort measurements in Local mode and connect the leafclip thermocouple and light sensor to the control unit. The leafclip may be held in the hand if multiple samples are being studied or mounted on a standard tripod mount via a thread in the lower clip section for fixed-position work.
  • The PAR sensor has been designed for both recording of ambient light intensities during fluorescence analysis and measurement of FMS actinic and saturating light sources during instrument setup.


Dark Adaptation Leafclips


  • A leafclip system has been developed for situations where ambient light is to be excluded from the sample during measurement using the FMS chlorophyll fluorometer. This is suitable for experiments requiring dark-adapted measurements e.g. screening applications measuring Fv/Fm or situations which require adaptation of tissue to standardised doses of actinic light.
  • The system consists of small, lightweight leafclips and 2 different types of fibre optic cable adapter. The leafclip itself has a small shutter plate which should be closed over the leaf when the clip is attached so that light is excluded and dark adaptation takes place. The body of the clips are constructed from white plastic to minimise the effects of heat build-up on the leaf during the period when the clip is in place.
  • The locating ring section of the clip which interfaces with the fibre optic adapter is also constructed from white plastic.
  • The sample rests on a foam pad whilst in the clip in order to minimise damage to the structure of the sample. The shutter plate should be closed to exclude light from the sample during dark adaptation.
  • During dark adaptation, all the reaction centres are fully oxidised and available for photochemistry and any chlorophyll fluorescence yield is quenched. This process takes a variable amount of time and depends upon plant species, light history prior to the dark transition and whether or not the plant is stressed. Typically, 15 – 20 minutes may be required to dark adapt effectively. In order to reduce waiting time before measurement, a number of leaves may be dark adapted simultaneously using several leafclips.
  • The fibre optic cable is inserted into either one of the adapters which in turn, fits over the locating ring of the leafclip. The closed fibre optic adapter is suitable for applications where ambient light must be excluded whilst the open adapter is suitable for studies under ambient conditions.

FMS2 Field Swappable Battery System

  • FMS2 Field Swappable Battery SystemThe FMS 2 chlorophyll fluorometer is powered by a 2.0 Ahr lead-acid battery, capable of 1 hour maximum of continuous actinic illumination or of delivering approximately 800 saturating pulses.
  • Up to four batteries may be charged in the FMS 2 multi-charger overnight and easily exchanged in the field as they become discharged.
  • 5 batteries are supplied with the FMS 2 which easily provide a full days measurement in the field. The FMS 2 carrying bag has space in the bottom to carry one spare battery.

Parameters Measured

Dark Adapted Parameters Measured : Fo,Fm,Fv,Fv/Fm

Light Adapted Parameters: Fs, Fm’ and ΦPSII, Fo’ and ΦPSIIR

Other Parameters Measured: PAR, Temp, qP, qNP, NPQ, ETR

Modfluor32 & Parview32 Software


  • PC control from Modfluor32 Windows® software allows real-time trace plotting as a chart-recorder emulation with calculated parameters written to a text parameters window.Instrument features and parameter measurement routines are selected from a toolbar with drop down menus to control file handling and instrument configuration.
  • Complex experimental protocols may be automated to reduce repetitive work by developing Scripts with Hansatech Scripting Language (HSL). An iconised Script Editor allows a sequence of control functions and measurements to be developed into a protocol. Once created scripts may be executed directly from the Modfluor32 program and data viewed while the instrument automatically completes a user-defined experiment. A maximum of six scripts can be downloaded to the instrument’s internal memory for operation without a computer.
  • Connection of an optional external battery enables portable operation with data stored to instrument memory for subsequent upload and full graphical presentation on the computer.
  • A further application is also included with the FMS chlorophyll fluorometer. Parview32 is a stand-alone utility designed to allow easy upload and transfer of multiple parameter files to a spreadsheet type program.
FMS2 Field Portable Pulse Modulated Chlorophyll Fluorometer
Dimensions 180mm (L) x 100mm (D) x 100mm (H). Weight: 2.0 kg including battery
Light Sources Modulation beam: Temperature compensated 594nm amber LED with 4 step frequency control (Optional 470nm blue LED)
Halogen source: Actinic up to 3000 μmol m-2 s-1, saturating up to 20,000 μmol m-2 s-1.
Far red: 735nm LED
Detector PIN photodiode with >700 nm filter
Detection Method Rapid peak pulse tracking
Sampling Rate Variable 10 Hz to 20 kHz depending upon instrument mode
Electronics 16 bit 165 microprocessor, 8 A/D channels 12 bit resolution, 4 external digital I/O lines, Single 12 bit buffered DAC (0 to 4095 mV)
Storage Capacity 256 Kb backed up RAM storing up to 2,430 full trace or 12,850 parameter only Fv/Fm data sets
User Interface 20 x 4 LCD display, 4 button keypad
Display 8 line x 20 character LCD display
Power Supply 5 x field replaceable 2.0 Ahr lead acid battery, 95 to 260 V universal input mains supply.
Leafclips PAR / temperature clip with cosine corrected PAR sensor (0 to 20,000 μmol m-2s-1) and thermocouple (-10 to 90 °C).
Remote trigger button and tripod mount.
10 x dark adaptation clips with fibre-optic adapters.