Ocean Optics S1024DW Install - Manual (Page 64)

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Appendix C: External Triggering
Our S2000 and S1024DW Spectrometers provide four
methods of acquiring data. In the Normal Mode, Ocean
Optics spectrometers are “free running.” That is, the
spectrometer is continuously scanning, acquiring, and
transferring data to your computer, according to
parameters set in the software. In this mode, however,
there is no way to synchronize the scanning, acquiring and
transferring of data with an external event.
To synchronize data acquisition with external events, three
other modes of acquiring data are available. Each mode
involves applying an external trigger to the spectrometer
before the software receives the data. The length of the integration time and the source for the integration
clock depend upon the mode chosen. All other acquisition parameters are set in the software.
For each external trigger mode, Pin 3 of the J2 (D-SUB-
15) Accessory Connector supplies voltage to the
spectrometer. To operate in the Software Mode, the
triggering device must be connected to Pin 8 of the J2
(D-SUB-15) Accessory Connector. To operate in the
Synchronization Mode, the triggering device must be
connected to Pin 5 of the J2 (D-SUB-15) Accessory
Connector. And to operate in the Hardware Mode, the
triggering device must be connected to Pin 4 of the J2
(D-SUB-15) Accessory Connector.
J2 (D-SUB-15) Accessory Connector (female)
External Software Trigger
In this level-triggered mode, the spectrometer is “free running,” just as it is in the Normal Mode. The
spectrometer is continually scanning and collecting data. With each trigger, the data collected up to the
trigger event is transferred to the software. If you continuously apply triggers, such as by holding down the
button on an external switch, this mode is equivalent to operating in the Normal Mode.
In the Software Mode, you set the integration time in the software. (It is the only external triggering mode
where the integration time is set in the software.) All other acquisition parameters are set in the software as
well. The source for the integration clock comes from the A/D converter.
Use the Software Mode if you:
•
are using a continuous illumination source, and the light intensity is constant before, during and after
the trigger
•
need to set the integration time in the software
To Use the Software Mode:
1. Supply a line from your triggering device to Pin 3 of the J2 Accessory Connector to provide the
positive voltage +5VDC to the spectrometer. (See figure above for pin location.) We do not advise
using an outside source to supply the voltage, as it is based on a referenced ground and your reference
may be different from ours. Using Pin 3 to supply voltage ensures that the spectrometer will receive
the appropriate voltage for the trigger event.