When creating an object how to know if to use GXDLMSData, GXDLMSRegister or the object in the library (such as GXDLMSClock)

Hello,

Thank you for this library. I am using my C# app to talk with an Italian gas meter. I am also using your GXDLMSDirector to help me unit test and develop in parallel. I've been able to connect, disconnect and read objects with both my app and yours.

One thing I can't figure out is when I should use GXDLMSData vs. GXDLMSRegister vs. the custom object in the library (such as GXDLMSClock)? If I pick the wrong one, it will not work. I get an exception such as "Access Error : Device reports a unavailable object."

For example, when I use GXDLMSData for the Logical Device Name (0.0.42.0.0.255) I can read the object. However, when I use GXDLMSRegister I cannot.
GXDLMSData dlmsObject = new GXDLMSData("0.0.42.0.0.255"); -> this one works
GXDLMSRegister dlmsObject = new GXDLMSRegister("0.0.42.0.0.255"); -> this one throws "Access Error : Device reports a unavailable object."

I wrote off the objects XML file using GXDLMSDirector and it seems to be a mixture of all three object types. For Logical Device Name the XML has GXDLMSData, which is the only object type that works in my C# app.

<GXDLMSData>
<LN>0.0.42.0.0.255</LN>
<Description>Logical Device Name</Description>
<Access>11</Access>
<MethodAccess/>
<Value Type="10">xxxxxxxxxxxxxxxx</Value>
</GXDLMSData>

I'm just wondering if there is a way for me to figure out which of the three object types I should be using? Initially I was just using GXDLMSData across the board, but I don't think that will work for every object.