Paramount Mounts do not allow a meridian flip before the meridian

Recently I resolved the issues I was having with getting meridian flips to work with SGPro, TheSkyX and my Paramount MX+ Mount. I determined that the Flip Hour Angle set on TheSkyX needs to correspond with that for SGPro, otherwise the OTA can end up on a different side of the pier to what SGPro is expecting. Therefore if I set the Flip Hour Angle on TheSkyX to 0 degrees and set the minutes past the meridian to flip also to zero degrees to 0, everything works perfectly. Equally, if I want to delay the flip until 60 minutes after the meridian, I can set the Flip Hour Angle to +60 minutes on both and once again it works fine. There may also be occasions where I would like to flip before the Meridian. However, when I tried to set a negative number in the “Minutes past meridian to flip” dialogue box in SGPro I got an error message saying ‘Your mount does not allow pier flips prior to crossing the meridian and your “Degrees past the meridian to flip” has been set to 0.’

Why not? From within TheSkyX, I can flip to either side of the Meridian with the press of a button, as long as the OTA is pointing within the slew limit envolope each side of the meridian.
Is this an issue with the ASCOM Driver for The Sky or SGPro?
Thanks Niall

I think this is a logic discussion. If you flip before the meridian and do centering, the mount would flip back with the final slew to the corrected position?

Thanks Chris, I will couch my answers as if I were in the Northern Hemisphere to avoid confusion. Remember that east and west are opposite for me here in Australia.
If the flip hour angle on TSX is set to say -30 mins, then if you ask TSX to slew to an object when it is 31 minutes before the Meridian, it will slew such that the telescope is on the eastern side of the pier. If, however, the objects is 29 minutes before the meridian, TSX will slew such that the OTA is on western side of the pier.
If I were to set the “Minutes Past the Meridian to Flip” on SGPro to -30 mins, if it would let me do so and supposing the last image finishes at 29 before the meridian, we would want a meridian flip to occur and as such, we would expect the OTA to flip from the eastern side to the western side. When a command is given to TSX to slew to the object it will correctly put the OTA on the western side, so I see no inconsistency whatsoever.
Since TSX can flip before or after the Meridian and will chose the correct side of the pier as long as the Flip Hour Angle is consistent with the “Minutes Past the Meridian to Flip” on SGPro, it should work before or after the meridian.
My feeling is that the author of the ASCOM Driver simply neglected to allow that possibility.

It is a bit more complicated than that. The ASCOM driver to TSX is multi-purpose. It is not just for Paramounts. Every mount has different capabilities and the driver does not know what is connected to TSX and what it can do. The driver developer is an SGP user and he related to me how the published API for TSX left too much to the imagination and the driver was a compromise. SB have released a 64-bit driver, to go with their 64-bit TSX beta. It would be nice to think they have ironed out a few ‘unhelpful charactersitics’ that have been there for ages, but don’t hold your breath.