Is there a command to change the STEM rotation angle?

Question

Does there exist a microscope control command in the DM scripting language to change the STEM rotation angle? That is, the direction the beam is moving across the sample. I would like to rotate 90 degrees between captures.

Answer 1

The scan rotation is part of the scan-parameter set.

You can not change it during a running acquisition. Instead, you restart the acquisition with a new parameter set.

( If you use the UI, then the rotation function does this for you. The scan restarts automatically. )

For scripting, you specify the rotation as a parameter either when starting an acquisition with DSAcquireData:

number dataType = 4   // 4 byte data
number width    = 128 // pixel
number height   = 128 // pixel
image img := IntegerImage( "Img", dataType, 0, width, height )        // Image has to be of type unsigned-integer
 

number signalIndex = 0
number rotation = 0   // degree
number pixelTime= 2   // microseconds
number lineSync = 1   // activated

DSAcquireData( img, signalIndex, pixelTime, rotation, lineSync )
ShowImage( img )

Or when creating a parameter set which you then use with DSStartAcquisition:

number paramID
number width    = 512 // pixel
number height   = 512 // pixel
number rotation = 0   // degree
number pixelTime= 2   // microseconds
number lSynch   = 1   // activated

number continuous  = 0 // 0 = single frame, 1 = continuous
number synchronous = 1 // 0 = return immediately, 1 = return when finished

paramID = DSCreateParameters( width, height, rotation, pixelTime, lSynch )

number signalIndex, dataType, selected, imageID
signalIndex = 0
dataType    = 2 // 2 byte data
selected    = 1 // acquire this signal
imageID     = 0 // create new image
DSSetParametersSignal( paramID, signalIndex, dataType, selected, imageID )
DSStartAcquisition( paramID, continuous, synchronous )
DSDeleteParameters( paramID ) // remove parameters from memory

Both examples above have been directly copied form the F1 help documentation on Digiscan: