C# DateTime Cannot be Used as a Method Argument

PLCnext Technology & PLCnext Controls
1

Stumbled on this odd behavior and eventually figured it out, no thanks to an extremely opaque error message: Error E1001: [optiPoint]OptipointLearningModule.compareMCV.compareMCVMainMethod() IL_00DC : critical internal error Error CILC0001 Error during generating native code.

After a bit of trial and error it became clear that you can’t use a C# DateTime type as an argument in a method for the PLC.
Further complicating the search was the fact that the code compiles fine if the method with the DateTime argument is not used by some other method.

I checked the “Known Issues and Constraints” section in the eCLR 3.2 Programming Reference but found nothing on this. Might be worth adding?

2

The valid data types that can be used in C# FBs are listed in the Readme.txt file that is included in every C# project, and in this table in the Info Center: https://www.plcnext.help/te/Programming/Csharp/Csharp_Supported_data_types.htm In addition, there are examples showing how to pass Date and Time variables to C# FBs, here: https://github.com/PLCnext/CSharpExamples/blob/master/PLCnext_CSharpExamples/09_DateTime/DateTime.md You can see that you are able to use the “DataType” attribute modifier to force the user to pass a variable of the correct IEC datatype, e.g. “LDATE_AND_TIME”. ~ Martin.