Issue:  After working relatively flawlessly for 4 years using POTH and then DH,   I’m suddenly unable to make a successful connection to my 12” LX200 GPS/R scope using the ASCOM Meade LX200GPS/R Driver (otherwise known as MeadeLX200GPS.Telescope). If the connection is made by means of DH, the principal error message is ‘Unable to write Telescope.Connected property’.

Description: Issue was first noted to occur in session S887 (2021-04-16).  It began as an error when trying to connect to scope from AstroMain. After then trying unsuccessfully to connect to scope directly from the DeviceHub window  all observatory software was exited/stopped & then restarted  whereupon the scope was successfully connected and the remainder of the session was completed ok.

In the attempted session S888A (2021-04-17)  the Scope connection problem again occurred from AstroMain, but no amount of restarting software, restarting scope, restarting computer was able to achieve a connection. In order to remove AstroMain from the equation software was cut back to just using DeviceHub and/or TheSky6 for problem investigation and was able to collect some diagnostic data but the session itself had to be abandoned.

Since then a series of further day time tests are been run, trying to connect to the scope and fix things So fart I have drawn a blank.
COM Port and settings have been checked and are all ok..

Issue appears to be the same as that reported by Marty Schultz using 16" LX200GPS scope back in 2009.  Replies suggest that driver's timeout is too short, but what has either changed the timeout or increased the process time. Cleaning keypad contacts eventually alleviated the issue in that case.  In attempting to fix issue is was noted that after time was set and the local and sidereal time on the scope read correctly the pointing is hours off in RA.  They hasto run a program to reset the timezone and time afterwhich the pointing matched up with their current model.   Mention is made of new Meade command  ":hIyymmddhhmmss#" for setting time/date correctly.  https://forums.dc3.com/showthread.php?3645-Connection-to-scope-stopped-working-through-ASCOM

Analysis:

• Observatory Computer is running Windows 7, with ASCOM 6.5 SP1 and there have been no recent updates/changes etc (nothing to explain this new issue)
  
  My normal process at the start of a session is to power on the scope (from its previously parked position) and after waiting for the scope to complete its start-up, I connect (via DeviceHub.Telescope) and the Telescope Driver auto sets the scope with the current time & date, and then I’m ready to go.
  ( I don’t use the GPS facility of my LX200 scope as I operate at a fixed site and the GPS Sensor struggles to get a GPS and Time fix when I have the secondary scope piggybacked onto top of main scope).
   
  
• When Telescope Connection is attempted from Device Hub a dialog box appears with error message ‘Unable to write Telescope.Connected property’
  
  The Device Hub  Activity Log shows
  
  
  11:18:26.612: Telescope - Others: Get Connected flag - False
  11:18:26.612: Telescope - Others: Set Connected flag -> True (failed)
   
  11:18:34.402: Telescope - Others: ASCOM.DriverException: Unable to write Telescope.Connected property ---> ASCOM.DriverAccessCOMException: Timed out waiting for received data ---> System.Reflection.TargetInvocationException: Exception has been thrown by the target of an invocation. ---> System.Runtime.InteropServices.COMException: Timed out waiting for received data
  --- End of inner exception stack trace ---
  at System.RuntimeType.InvokeDispMethod(String name, BindingFlags invokeAttr, Object target, Object[] args, Boolean[] byrefModifiers, Int32 culture, String[] namedParameters)
  at System.RuntimeType.InvokeMember(String name, BindingFlags bindingFlags, Binder binder, Object target, Object[] providedArgs, ParameterModifier[] modifiers, CultureInfo culture, String[] namedParams)
  at System.Type.InvokeMember(String name, BindingFlags invokeAttr, Binder binder, Object target, Object[] args, CultureInfo culture)
  at ASCOM.DriverAccess.MemberFactory.CallMember(Int32 memberCode, String memberName, Type[] parameterTypes, Object[] parms) in C:\ASCOM Build\Export\ASCOM.DriverAccess\MemberFactory.cs:line 330
  --- End of inner exception stack trace ---
  at ASCOM.DriverAccess.MemberFactory.CallMember(Int32 memberCode, String memberName, Type[] parameterTypes, Object[] parms) in C:\ASCOM Build\Export\ASCOM.DriverAccess\MemberFactory.cs:line 368
  at ASCOM.DriverAccess.AscomDriver.set_Connected(Boolean value) in C:\ASCOM Build\Export\ASCOM.DriverAccess\AscomDriver.cs:line 170
  at ASCOM.DeviceHub.TelescopeService.set_Connected(Boolean value) in C:\ASCOM Build\Export\Drivers and Simulators\ASCOM Device Hub\DeviceHub\Services Classes\Implementations\TelescopeService.cs:line 73
  --- End of inner exception stack trace ---
  at ASCOM.DeviceHub.TelescopeService.set_Connected(Boolean value) in C:\ASCOM Build\Export\Drivers and Simulators\ASCOM Device Hub\DeviceHub\Services Classes\Implementations\TelescopeService.cs:line 81
  at ASCOM.DeviceHub.TelescopeManager.set_Connected(Boolean value) in C:\ASCOM Build\Export\Drivers and Simulators\ASCOM Device Hub\DeviceHub\DeviceManagers\TelescopeManagerAccess.cs:line 118
  
   
  
• When connection is attempted from TheSky6  a TheSky TeleAPI ASCOM dialog box apperas with the error message ‘The selected telescope driver is missing the Connected property’
   
  
• Although scope can not be connected to using either DH / MeadeLX200GPS.Telescope or using TheSky / TeleAPI / MeadeLX200GPS.Telescope (this was for diagnostics testing: TheSky6 is normally set to use TeleApi / DeviceHub.Telescope)  it is possible to connect to and operate the scope if TheSky6 Telescope is set to use its native telescope/control system called ‘LX200 GPS by Meade Instruments Corporation’ (time/date have to manually set on the scope first uwhen using this method). This would seem to indicate that the scope & cabling/comms are working ok.
  
  This of course doesn’t provide a practical solution for the Clair Dome observatory as it doesn’t provide me with either Slaved Dome operations, or multi-client access to Telescope Info from my client programs,  PHD2 etc
  
  (For computer connection to the LX200 Telescope  a Pierro-Astro USB-RS232 cable with integrated interface for LX200 is used. Its a single 1.8m cable with RS232 plug at one end and USB plug at the other, rather than a traditional 2 or 3 element solution . I’m without a working alternate USB/Serial Adapter at the moment, so its an assumption that since cable/comms are good for TheSky6’s native LX200 GPS telescope then they should be ok for the MeadeLX200GPS.Telescope driver. (this is an assumption).
   
  
• If MeadeLX200GPS.Telescope properties page is accessed from DeviceHub's Telescope Setup  the expected ‘ASCOM Meade LX200GPS/R Setup’ window with fields of Serial Port, Autoset Time checkbox etc. are visible ok (.png picture ATTACHED)
  
  If attempt is made to open the  MeadeLX200GPS.Telescope properties page from TheSky6/TeleApi (ensuring that the driver isn’t open elsewhere) an ‘ASCOM Chooser’ dialog is displayed with the error message ‘Failed to load driver “MeadeLX200GPS.Telescope” with System.UnauthorizedAccessException: Creating an instance of the COM component with CLSID .... (.png picture ATTACHED).
  
  ( I don’t normally have the MeadeLX200GPS.Telescope tied directly to TeleAPI, so don’t know if this error message is associated with my connection issue or whether it would have appeared previously. When TeleApi is set to DeviceHub.Telescope clicking Properties from the ‘ASCOM Telescope Chooser’ brings up ‘Device Hub Telescope Setup’ and from there the ‘ASCOM Meade LX200GPS/R Setup’ is accessible ok )
   
  
• If I change the DH Scope to using ‘Telescope Simulator for .NET’ I can connect to the telescope simulator ok but that doesn’t help me with the requirement to connect to my LX200 Scope
   
  
• Thinking that there may be some corruption of the telescope driver I downloaded and installed a new copy of the MeadeLX200GPS driver from ASCOM Telescope Driver Downloads ( MeadeLX200GPS(5.0.0)Setup.exe) but this didn’t resolve things. It produced the same errors as before.
   
  
• Some tests were also performed using my Development Computer (Windows 10 with ASCOM 6.5 SP1). This was to remove my Windows 7 Observatory Computer from the equation, but I encountered precisely the same results as when I was using the Windows 7 Observatory Computer :
  - Can’t connect using DH with MeadeLX200GPS.Telescope : ‘Unable to write Telescope.Connected property’
  - Can connect using TheSky6 with its native ‘LX200 GPS by Meade Instruments Corporation’ telescope.
  - Can get ‘ASCOM Meade LX200GPS/R Setup’ window via DH
  - Can’ get setup window from TheSky6 (gives the Failed to load driver / UnauthorizedAccessException: Creating an instance of COM component etc)
   
  
• TeleAPI is not considered to be a factor in respect of the issue : Whilst a TeleApi problem might explain an issue connecting to Scope from TheSky6, it can’t explain failure to connect to scope from DeviceHub.
   
  
• Whilst it may be a red-herring it was noticed that during testing in the last few days logs have picked up the occasional exception when connecting to the Dome using AstroMain (client).  These read
  ’Exception whilst getting Dome.Connected property’.
  ‘CheckDotNetExceptions ASCOM.DeviceHub.Dome CanPark Get System.NullReferenceException: Object reference not set to an instance of an object.’
  
  ( This is not an exception that I recall seeing before in logs. This might be a sideffect of DH having had an issue connecting to the Scope or me doing things in a non-normal order or it may represent something significant/useful. I don’t know. Regardless of this the Dome Connection appears to be generally working ok. )

Conclusion

Action:

  Try out Colin Dawson's MeadeGeneric Driver to see if it can be a replacement for the MeadeLX200GPS driver     (see MeadeGeneric driver)
  Try fresh attempts to connect to scope using the MeadeLX200GPS driver
  Explore use of Meade ":hIyymmddhhmmss#" for by-passing Date Prompts and setting time/date correctly.

Update 2021-04-23

MeadeLX200GPS driver was found to be capable of connection to the observatory's LX200 GPS/R scope but only if the 'Auto Set Time' option is turned off.
 
(MeadeLX200GPS driver continues to be unable to connect to scope with the Auto Set Time option turned on.   This issue developed during the course of session S887 (2021-04-16) and meant that attempt at an observing session the following night (S888A, 2021-04-17) had to be abandoned. This driver dates from 2005-2007 and is no longer supported.   This has prompted an effort to see if the MeadeGeneric driver (written & supported by Colin Dawson) can already and can be made capable for filling into the role of the MeadeLX200GPS driver).   Whilst 'Auto Set Time' feature has been added to Meade Generic driver following contact with driver's author there are two critical issues that make the Meade Generic driver unpratical for use during a live session.

Update 2021-04-24

MeadeLX200GPS driver was found to be capable of connection to the observatory's LX200 GPS/R scope but only if the 'Auto Set Time' option is turned off.
 
Updates to MeadeGeneric driver eventually allowed 1.0.1.327 Dev Build  to be used to run session S890 (2021-04-24) without the problems that affected the badly affected the two preceeding sessions S888 & S889 that were using older 1..0.0.296 version.