KSLightBox

KSLightBox is a dialog-based program, which provides a range of options for:

  • Driving a single-turnover flash source (LEDs or a Xenon flash lamp)

  • Calibration and control of a pulse-width modulated LED actinic source

  • Temporal control of a pulse-width modulated LED actinic source

    •

    Main dialog
    Interface settings dialog
    LED calibration dialog
    Light regime dialog

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    The program was written to meet some specific requirements:

    1. The 'Flash source' section of the program was designed to trigger sequences of saturating, single turnover pulses from an array of LEDs to suspensions of pelagic algae. The release of oxygen from water oxidation at PS II was measured simultaneously, using a chart recorder.

    2. The 'LED actinic source' section was designed to provide straightforward control of an LED light source, through pulse-width modulation (pwm).

    3. The 'Light regime' section of the program was designed to provide a simple, automated method for running a multi-step light curve (time zero mode) and running a growth chamber or growth vessel lighting system (time of day mode).

    It is possible to run 1 and either 2 or 3 at the same time through one copy of the program. Several copies of the program can be run simultaneously.

    TTL pulses for driving both the flash lamp and actinic light source are provided through a counter-timer device. Currently, the National Instruments PCI 6601/2 and E-series cards are supported by the program. Support for the National Instruments M-series cards will be added in the near future. Several copies of the program can share the same card, the only limitation being the number of counter-timer devices on the card.

    Main dialog

    The main dialog provides a simple interface for controlling a flash source and LED actinic source.

    Settings file:

    When the program is started, a default settings file is loaded. Additional settings files can be loaded and saved (see below).

    Flash source:

    Pulse length (µs)
    Sets the length of each TTL pulse from the counter-timer device. This will be the on time for an LED source. For a Xenon flash lamp, the pulse length is not critical, since the pulse length is determined by the characteristics of the flash lamp drive circuit.

    Pulse interval (ms)
    Sets the interval between the start of two consecutive TTL pulses. It is the user's responsibility to ensure that this interval is not too short for the type of lamp being triggered. For example, too short an interval with over-driven LEDs will damage the LEDs while too short an interval with a Xenon flash lamp will result in low flash energy and possible damage to the drive circuitry.

    Flash run duration (s)
    Sets the time for a flash run.

    Start run
    When this button is pressed, the edit boxes associated with the Flash source switch to 'read only' mode, the remaining flash run time is shown and the 'Start run' label changes to 'Stop run' (see below). If the run is allowed to complete, the dialog reverts to the original condition.

    LED actinic source:

    Required PI (µmol m-² s-¹)
    This is the photon irradiance required by the user. An appropriate TTL pulse length and duty cycle is selected by the program to deliver this required photon irradiance, using the calibration data entered by the user through the LED calibration dialog. If a regime is being run, this setting will be overridden by the current regime setting within 0.5 s.

    Clicking the right mouse button within the dialog brings up a menu with 5 options.

    Interface settings
    Launches the Interface settings dialog. The interface values must be set before the program can be used.

    LED calibration
    Launches the LED calibration dialog. The calibration values must be set before the actinic light functions (including the light regime functions) can be used.

    Run light regime
    Launches the Run light regime dialog.

    Save settings
    The current settings can be saved to file using this function. The naming convention for this type of file is *.lbs. The capacity to maintain several settings files is particularly useful when running several copies of the program simultaneously: for example, when controlling multiple different colours of LED within a single experiment.

    Load settings
    When the program is started, the last settings used are loaded from a file called KSLightBox.def. These settings can be overwritten by loading a *.lbs file that was previously saved using the 'Save settings' function, above.

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    Interface settings dialog

    Device type:
    This selection should match the interface card that is being used to provide TTL pulses to the light source(s). See the National Instruments website for details of the supported cards (PCI 6601, PCI 6602, PCX 6602 and most E-series devices).

    Device number
    This is provided by the National Instruments 'Measurement and Automation' program, which is installed with the NI-DAQ drivers.

    Flash CT line
    The number of the counter-timer line used to provide TTL pulses to the flash source.

    Flash DIO line
    The number of the DIO line used to determine the on/off status of the flash source.

    Actinic CT line
    The number of the counter-timer line used to provide TTL pulses to the actinic light.

    Actinic DIO line
    The number of the DIO line used to determine the on/off status of the actinic light.

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    LED calibration

    Pulse length:
    The length of the 'on' (TTL) pulses that are used to drive the LEDs at each calibration step.

    Duty cycle:
    The 'on' time at each calibration step.

    PI:
    The photon irradiance (in µmol m-² s-¹) at each calibration step.

    The program sets the appropriate pulse length and duty cycle as the user moves the focus among the PI edit boxes. It is the user's responsibility to ensure that the numbers in the PI edit boxes are accurate. These calibration data are used to set the requested output of the LED actinic source.

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    Light regime dialog

    This is a modeless dialog. It allows the user to set and run a light regime.

    Time base:
    Timing for the light regime can start at 'Time zero', when the Start button is pressed, or 'Time of day', which runs from the computer clock.

    Regime name
    If running several copies of the program, it can be useful to give each copy its own name. In the example above, this copy of the program is controlling a bank of orange LEDs. Other copies of the program might control different colours of LEDs, forming a multi-coloured LED lighting system.

    Current step
    This is updated by the program when a regime is being run.

    Step:
    Up to 12 steps can be set. Each step is activated by ticking the Step check box. Times do not have to be sequential, but it obviously makes the regime easier to follow if they are.

    h: m: s:
    The timing for each step can be set to the nearest second.

    PI:
    The photon irradiance that will be set at each step of the light regime (in µmol m-² s-¹).

    Start/Stop
    When the Start button is pressed, the regime is started and the button label changes to 'Stop'.

    Pause/Resume
    When the Pause button is pressed, the button label changes to 'Resume'. The current PI remains in force until the button is pressed again.

    Update
    New entries or changes to existing entries are not valid until the Update button is pressed or the dialog is closed.

    Close
    This closes the dialog, but does not stop a regime from running. If the dialog is started again, it will resume the condition when the dialog was closed. If the user tries to close the KSLightBox program while a regime is running, a warning is given, whether the Light regime dialog is open or not.

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