Ocean Optics Torus Operating Instructions - Manual (Page 23)

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Appendix B
External Triggering
Overview
The Torus supports four triggering modes, which are set with the Trigger Mode command. Details of each
triggering mode follow.
Normal (Free Running)
In this mode, the Torus uses the user-defined integration clock and continuously scans the CCD array.
All of the signals described in the previous section are provided by the spectrometer to the CCD
automatically based on the integration time selected in the software by the user.
External Software Trigger
In this mode, the ExtTrigIn signal acts as an enable switch. If ExtTrigIn is kept HIGH, the Torus will
acquire spectra as if it was in the normal free running mode. If ExtTrigIn is kept LOW, the Torus will not
acquire spectra.
External Hardware Trigger
On the Torus, Ocean Optics has altered the functionality of the External Hardware Trigger function and
reprogrammed the Single Strobe signal function. These alterations of the USB2000 enable you to operate
in the Variable Delay Mode without the presence of an external trigger signal. The Torus will simulate the
signal to trigger the appropriate circuitry in the spectrometer.
The table below summarizes the capacity of the Torus in Variable Delay Mode:
Parameter Value in Normal Acquisition Mode Value in Variable Delay Mode
Integration time User controlled 5 ms fixed
Strobe delay 0
µs
2 – 511
µs + 3 µs
Jitter < 25 ns < 25 ns