Try changing this line:
public static PCOMMSERVERLib.PDeviceClass Turbo;
to:
public static PCOMMSERVERLib.PDeviceClass Turbo = new PCOMMSERVERLib.PDeviceClass();

I already had this on top of the file as:
PDeviceClass Turbo = new PDeviceClass();
It is still pointing to the line:
Globals.Turbo.Open(Globals.device_number, out Success);

Hi Vulpes,
It's working now. I was declaring the object out of the global class!
Thanks!

Hi,
If I have a method called Turbo.GetResponse(int dwDevice, string question, bool bAddLF, out string pAnswer, out int pstatus);
And I declare each of these variables as separate names in my Globals class, can I access them using Globals.Turbo.GetResponse(Globals.device_number, Globals.command, Globals.false, out Globals.response, out Globals.status)

Yes, you could store those static variables in your Global class as well.
Notice though that Globals.false wouldn't be allowed as 'false' is a keyword. You could, however, use Globals.False instead.

I am unable to access string variables from my Globals. It only shows Globals.device_number.
I have even made my string variables public. Still cannot access them in the solution.

string command;
should be:
public static string command;
I'd also make Globals into a static class so that you don't inadvertently add any instance variables.

Hi,
What is the reason that I need to declare these variables as static?
Regards,
AVM

It's best to make them static so you don't have to create an instance of the Global class to access them - you can just prefix them with the class name.
Global variables are in any case naturally static because they have the same value throughout the application.
Making the class into a static class ensures that you can't create an instance of it as all members must then be static.