Modicon M580 and diagnostic CRA module

How to write diagnostic for CRA module, and more specifically how to work with words and bytes in Unity Pro. I am new with Scheider and it would be helpful if somebody could provide some examples of real projects or realy big projects. Tahnk everybody.

When you create a CRA module, it should automatically create a DDT structure of type T_M_CRA_EXT_IN. The default name is MOD_COM_1 but that can be changed in the device settings to whatever you want. This is a screenshot of what it looks like.

The DDT should have all the diagnostic variables you need. If you do a search in the help files for T_M_CRA_EXT_IN, there should be a detailed explanation of what each DDT variable does. I don't know what you mean by 'write diagnostics' though - what exactly do you need to write to the CRA module?

Yes, I saw all these variables, I mean which of these variables should be used to check the status of CRA module, and how to write a program that will handle all of these variables. For example CRA_STATE byte shows in which mode is the module, how do I make a program that would be check and show me module status. And in general how to work with words, bytes.

You use them as you would a regular PLC variable. Like I said before, all the info on how to interpret the CRA DDT variables can be found in the Unity Pro help files.

For the DDT variables that are bits packed into a byte or word, you can extract the individual bits using the BYTE_TO_BIT or WORD_TO_BIT functions.

In some cases (e.g. CRA_STATE) where the digital status info is stored as integers rather than bitwise, you can do a simple compare with the EQ function.

If you need to make the DDT variables addressable for external comms (SCADA, etc.) then just remap them or use aliasing.

ok thank you, I will try to do this