Some follow up:
Last night I powered everything on and ran a set of flats. The filter wheel ran normally and changed when it was supposed to. The sequence completed successfully.
I then restarted everything, just to make sure everything was fresh. I started my sequence, which was to start with filter 2 (red) and it failed right off the bat with the same error. I moved the USB cable to a different hub, restarted the laptop and equipment again. Same result, failure saying it could not set filter position. I did notice that the filter module in SGP was always saying the wheel was moving when it was not.
So, pretty frustrated at this point. I was looking around at the settings in SGP and decided to put a 10 second filter change delay. The sequence then started and ran without problems, changing filters as needed. I put in a second target while the first was running with four more filter changes and it completed them as well.
I have only tested this out once but it seemed to work so far. We’ll see if it continues…
This now makes two pieces of equipment I have to add delays for because ASCOM polling (correct term?) doesn’t seem to work. The other is my CEM60 mount. I have to put in a 60 second settling time or it fails to meridian flip. The flip actually happens but SGP thinks it is done while still slewing and fails because it has not yet changed pier side and the driver is not correctly reporting a slew in progress. Unfortunately there seems to be variation in the interpretation of the ASCOM standards throughout the industry. I’m not trying to blame anyone in particular, just noting the problem.