User`s guide

ACQUISITION MODES
SDK SECTION 4
Page 36
Accumulate
Accumulate mode adds together (in computer memory) the data from a number of scans to form a single
‘accumulated scan’. This mode is equivalent to taking a series of Single Scans and “manually” adding them
together. However, by using the built-in Accumulate mode you gain the ability to specify the time delay (or
period) between two consecutive scans and also the total number of scans to be added.
To set the acquisition mode to Accumulate call:
SetAcquisitionMode (2)
To fully define an Accumulate acquisition you will need to supply the follow information:
Exposure Time. This is the time in seconds during which the CCD sensor collects light prior to readout. Set
via the SetExposureTime function.
Number of Accumulations. This is the number of scans to be acquired and accumulated in the memory of
the PC. Set via the SetNumberAccumulations function.
Accumulate Cycle Time. This is the period in seconds between the start of each scan.
Set via the SetAccumulationCycleTime function. (This parameter is only applicable if you have selected
Internal trigger – Please refer to SECTION 6 – TRIGGERING for further information.
NOTES:
1. If the exposure time or the cycle time are set too low or are not permissible values, the driver
will automatically calculate the nearest appropriate value.
2. The actual values used can be obtained via the GetAcquisitionTimings function (this
function should be called after the acquisition has been fully defined (i.e. readout mode,
trigger mode etc. have been set).
3. In External Trigger mode the delay between each scan making up the acquisition is not
under the control of the Andor system but is synchronized to an externally generated trigger
pulse.