User`s guide

TRIGGERING
SDK SECTION 5
Page 57
Software
In Software Trigger Mode, once an acquisition has been started via the
StartAcquisition function, the user
software determines when data is actually acquired via the SendSoftwareTrigger command. This will give
full control to the user software to ensure that it only requests an acquisition when it is ready. It permits the
highly efficient upload of new exposure times between acquisitions and even allows a pre-load of up to 16
exposures to the camera which will be cycled through with each acquisition. It also permits the user
software to perform certain actions before requesting the next acquisition, such as moving an external
stage or even to change the exposure time.
Note that not all systems support Software Trigger mode. To check if these enhanced features are
available with your system, use the function GetCapabilities and check the ulTriggerModes variable for bit 3
(AC_TRIGGERMODE_CONTINUOUS) being set. If this bit is set and the system is configured with the
following modes:
• Read mode set to image
• Acquisition mode set to Run till abort
• Trigger mode set to 10
Then the SendSoftwareTrigger command will cause the acquisition to be taken.
It is recommended that you call IsTriggerModeAvailable(10) to check if your system is set up to use the
SendSoftwareTrigger function.
If a SendSoftwareTrigger command is issued when the camera is not ready for it, it will be ignored and an
appropriate return code returned.
The extra functionality of pre-loading exposures (up to a maximum of 16) to the camera is configured with
the SetRingExposureTimes command. When the first acquisition is requested (SendSoftwareTrigger) the
camera will take an acquisition with the first exposure in its list. When the second acquisition is requested
the next exposure in the list will be used and so on. When the camera uses the final exposure in its list it
will loop to the beginning again.
Notes on Frame Transfer
• On Frame Transfer systems, the Frame Transfer mode can be activated or deactivated. Currently,
not all cameras can take advantage of the frame transfer operation in Software Trigger mode. By
the nature of frame transfer, an exposure can be occurring when the previous acquisition is being
read out. Currently, no PCI connected cameras can be sent a software trigger when the
camera is reading out.
• USB cameras that support Software trigger can be sent a software trigger command during
readout.
• Frame transfer is fully supported in external trigger mode.