Concon, you can definitely do what you want. It's been some time since I set up my system (StackShot controller driving a microscope focus block), so forgive me if the following suffers from fuzzy memory.concon wrote:After adjusting the settings within the advanced configuration I was expecting to see the step size change when getting a stack ready; I had expected the 1um minimum step size to adjust to a new step size determined by the controller with the given input parameters. I'm reading the instructions to my best of my ability (haven't found a place they reference using a different rail, and have reached out to their support. I imagine that the 1um is a hard limit within their controller, based on my experience so far. I continue to see Zerene being being mentioned- is this a necessity to accurately see the new step size?
Thanks again- almost there!
Originally, the minimum step size that could be set via the StackShot controller was much larger than I needed. I believe Cognisys has addressed this in subsequent firmware versions. However, there is perhaps still a minimum number of microns that can be set on the controller, and this may be too large for your needs. If so, there are at least two ways of getting around it.
Method one: Fool the controller into overcounting the travel distance. Look at section 3.13.1 in the StackShot manual: Distance per Revolution. This section tells you how to inform the controller how far your rig moves per turn of the motor. If the controller has a one-micron minimum, and you prefer a 1/10 micron minimum, simply set the per-turn distance to 10 times the actual distance your rig travels. Then when using the controller, just remember that "one micron" set on the controller really translates to 1/10 micron of actual travel.
Method two: Set the controller so that in daily use, you enter the number of motor steps of travel you desire, instead of entering a desired distance of linear travel. This is my preferred method. See section 3.3.10 in the manual: Units of Measure. Select "Steps." Ignore the specific details that follow, as they apply to the StackShot rail, not your hardware. Then calculate the number of steps you want to use with each lens, and make yourself a handy chart. Be aware that when Cognisys writes "steps," they really mean "microsteps." In this case, a microstep is 1/16 of an actual motor step.
So the math works out like this (I'll use the example of my focus block):
- Focus block moves 100 microns per turn of shaft
Motor has 400 steps per turn
So travel per "step" = 100 microns/(400*16) = 0.015625 microns.
As examples, here are settings I use with my hardware and the following lenses:
- Mitutoyo 5x/0.14: 1184 "steps" (18.5 microns)
Mitutoyo 10x/0.28: 304 "steps" (4.75 microns)
Mitutoyo 20x/0.42: 112 "steps" (1.75 microns)
Mitutoyo 50x/0.55: 48 or 64 "steps" (0.75 or 1 micron)
Mitutoyo 100x/0.70: 32 "steps" (0.5 micron)
--Chris S.