Extreme EOS Shutter mode

Some events can be very demanding requirements for imaging frame rate, for example eclipses, transits, occultations and etc. To cover these needs APT provides the "Extreme EOS Shutter mode" (EESM) when Canon EOS cameras are used. Currently this mode is not supported for Nikon cameras.
The "Extreme EOS Shutter mode" uses serial or DSUSB cable to shoot images as fast as possible and allows to boost the imaging frame rate from 1 image on every 2s to 1-2 images per second (depends on the camera and memory card speed).
To enable EESM there is need to set some settings - the Image Destination in the Camera tab has to be Camera only, Image Preview has to be Disabled and serial cable or DSUSB has to be used as Long Exp Control. The idea is to store the images on the camera card and do not waste time to transfer them to the computer for previewing. The Serial/DSUSB cable provides much faster way to start exposure than the USB communication (limitation of the Canon's communication library).
To get most of EESM make sure that the sounds are disabled, in the plan editor the option "Don't Dither This plan" is better to be checked. Also make sure that image display is disabled from the camera menu.
Having all that set you have to determine how fast your "camera + card" combo is. Make a plan with 20 exposures (RAW only image quality is suggested to save space and time) with duration equal to the shortest you will use and pause set to 0s. Point the camera to some light (darker images are smaller than bright one and take less time to be saved). Repeat the following test.
1. Clear the card
2. Execute the plan
3. check if you have 20 images in the card
4. if you have 20 images lower the value Extreme EOS Shutter delay in Advanced settings tab. Repeat from point 1
5. if you have less than 20 image increase the value Extreme EOS Shutter delay. Repeat from point 1
In the end you will know what is the minimum delay that can be used. Now build the Imaging Plan with all exposures you are planning to execute during the event and make the same test above. The changing of ISO and/or Exposure settings require time, so most likely you will need a bit longer delay, so you will have to determine the right one.
Now you are ready extreme imaging of the event.. You can combine your plan with execution scheduling.