invalid descriptor

[weedman]

We are a manufacturer of Foundation Fieldbus I/O and are in the process of updating our stack.  After upgrading and installing new NI-FBUS software to version 3.2.3, I am having problems trying to test one of our Device_Types.  An error comes up INVALID_DISCRIPTOR, and then SERVER CONNECTION IS LOST. 

All the device types previous to the stack change, and even one of the devices after the stack change test and communicate fine.  The particular device in question has the ANALOG IN and OUT function, so the DD/CFF is different from the other device that has worked fine after the stack change.  The DEV_TYPE, DEV_REV, and DD_REV will all come up as NULL also.

My question is is it possible the DD/CFF file is corrupt?  How is the desciptor communicated between the device and the communication manager in the software?  We are working with our developer as well to resolve this but they have seen no problems.

I should also mention, all the devices above, including the one I am having problems with, worked fine on our previous version of NI-FBUS (2.3.6).

[Vince Shen]

One possible reason is that the DD file you use is not compatible with NI-FBUS 3.2.3.

NI-FBUS 2.3.6 and 3.2.3 uses different version of DD Service (DDS) library. DDS library is provided and maintained by Fieldbus Foundation. NI-FBUS Communications Manager use DDS library to load and interpret the DD.

NI-FBUS 2.3.6 use DDS 4.0 while NI-FBUS 3.2.3 use DDS 5.0.5. The DD created by DDS 4.0 may not work on DDS 5.0 system.