Exported Clocks

ScanImage can export various clocks such as the beam-modified line lock, frame clock, volume clock, acquisition clock, or frame clock.

Clock Terminals

Not all the clocks are available for all the scanner systems. If using a linear scanner, there is no line clock; the beam modulator control signal is buffered for a frame at a time and triggered off of the frame clock.

Tip

If a line clock is required from a linear scanner, then a pseudo beam modulator device can be configured with 0 to 5V command voltage range. Then the power for this pseudo beam modulator can be set to 100% and the analog output for this beam modulator will effectively provide a line clock.

For the vDAQ, the terminals that clocks are output on are user selectable from the imaging scanner page.

For NI hardware, these terminals are already set. Here is a table summarizing when clocks are available for different scanner systems using NI hardware:

Scanner System	Beam-Modified Line Clock	Frame Clock	Volume Clock	Acquisition Clock	Reference Clock
Linear Scanning		PFI10			PFI14
Resonant Scanning	PFI5	PFI6		PFI7	PFI14

Here are definitions for each of the clocks:

Clock	Description
Beam-Modified Line Clock	A line clock that is offset by the beam lead time set from the beam controls window. This is available only for resonant scanning. It is high when the beam modulator is modulating during a line, and low during turnarounds.
Frame Clock	A clock that is high during the raster scan of the frame and low during the y-galvo flyback.
Volume Clock	A clock that is high during acquisition of the volume and low during fastZ flyback.
Acquisition Clock	A clock that is high during an acquisition in a loop and low during the interval time between.
Reference Clock	A clock that can be used to synchronize timebases between different DAQs. The frequency is user settable and has a 50% duty cycle.