Dave Mitchell's DigitalMicrograph™ Scripting Website

A free lens control unit for older (serial communication) JEOL TEMs. This will allow the application of offsets to existing lens values, it will allow the setting of specific lens values. It will also capture a current lens setting and save it, enabling custom lens configurations to be recalled. It also enables degaussing of lenses, to minimise hysteresis.

There is a lot of functionality in this script, and when launched a detailed list of instructions is printed to the Results window.

Serial communication must be established between the microscope and the Gatan PC for this script to work. This requires the JEOL TEM to be in external control mode (type EXT_1 at the JEOL keyboard (note _ is a space)). If DigitalMicrograph currently sources the magnification from the TEM when acquiring images, then communication is established. The JEOL hardware Free Lens control unit was an optional extra, but free lens mode was always accessible via the internal ECL command line language - albeit in a very clunky fashion. This script is much more flexible than either the command line or the JEOL hardware and brings additional functionality in the form of degaussing and much more facile saving and recall of custom lens configurations.

Each JEOL model uses different lens configurations. JEOL label lenses 0, 1, 2, 3 from the top down. Some lenses (such as lens 7 on my 2010) are not implemented. The lens descriptions for your microscope will appear in the ECL language reference section of your manual, or you can work it out by changing lens settings in the script while looking at the PRTEST M2 page on the TEM screen. To make the script generic, the number of lens fields is variable and out of the box they are labelled Lens 0, Lens 1 etc. You should rename the lenses to match your instrument such as Cond 1, Cond 2 etc. Any lenses which are not implemented should have the name set to blank, and that row in the dialog will then be disabled. The number of lenses is set in the Global Info for this script, and should be set to match your microscope (see the Instructions in the Results window - when you launch the script). The Projector lens should be the last lens in your list - if you source 'lens' info after the projector it is actually deflector data you are sourcing - do not do this.

I have not ported this script (yet) to work with the new crop of JEOL TEMs which use ethernet communication (1400, 2100, 2200, ARM), but will do once my ARM is operational.

This tool accesses lens values only (not deflector or stigmator values) and any changes it applies are only temporary. If you press Reset in the script dialog, or push the Free Lens button on the JEOL hardware (if fitted), or type LFCOFF at the JEOL keyboard, the changes are cancelled and the microscope is back in its standard configuration. There are other scripts which enable you to save a complete snapshot of all lenses, deflectors and stigmators (Save JEOL Microscope Configuration) and to recall them (Restore JEOL Microscope Configuration).