I am not actually trying to use two filter wheels at the same time. I basically have one with color-related filters attached to my color camera and one with mono-related filters attached to my mono camera, so depending on what camera I am using on a night I need to distinguish between the color or mono filter wheel.

However, to answer your specific question, I just plugged them both in at the same time and one shows up as "ASI EFW 0" and the other shows up as "ASI EFW 1".

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