OK I just updated the QHY driver, restarted my computer, and the problem persists.
Attached is a log that I successfully captured 100 flat frames, and then wanted to capture 100 more flat frames when TEC temperature reads NA again.
To recover from this, I connected and disconnected from the Camera in SGP and it worked again.
[05-27-17 13:07:53.314][DEBUG] [CP Update Thread] ASCOM Camera: Error in GetCoolerTemp. : value of CCDTemperature is invalid. (System.Reflection.TargetInvocationException: Exception has been thrown by the target of an invocation. —> System.Runtime.InteropServices.COMException: value of CCDTemperature is invalid.sg_logfile_20170527124014.zip (81.7 KB)
Where is ASCOM Camera log please? I am not familiar with its location.