Dave Mitchell's DigitalMicrograph™ Scripting Website

The CameraManager object provides commands to manage cameras and their shutters. This can get a bit complicated as there may be multiple cameras each with multiple shutters. Typically, shutter zero uses a gun deflector to shift the beam off the specimen. This is fine for typical specimens which are not charging. For specimens which charge up when the beam is moved onto them, using a post-specimen shutter (which keeps the illumination on the specimen and allows it to reach steady state in terms of charge build-up), is advised. Such shutter positions may include mechanical or electronic deflectors further down the column (below the specimen) or electromagnetic or electrostatic deflectors in the GIF (if present). Anybody writing scripts which require beam blanking, are most likely looking to minimise electron dose between frames, and so gun deflector shuttering is the one to use.

The best way to understand your shutters is to have your camera producing a live updating image of perhaps 2s exposure (use 1x binning so that the read out takes a long time - the refresh rate of the deflector values in the microscope interface may otherwise be too slow to pickup shuttering reliably) and monitor the microscope interface to see which deflector (eg Gun Def) is changing.