Hi alexart,
There are two ways to do what you are trying to do with your MODBUS slave. You can see in this KnowlegeBase article that the two options are to use the DSC Module, or to make use of the MODBUS library.
It
seems that you are attempting to recreate the functionality of the
MODBUS library, which is going to be much more trouble that it is
worth, since the library can be downloaded for free from the link above.
Regards,
Stephen S.
National Instruments
Applications Engineering
