Symptoms

While the NetLinx master is running a program, the following runtime error is seen in diagnostics:

CipMan:RunMainLine - Null Table Error 6

In addition, modules defined in the program may not be working properly.

Cause

One known cause of this error is defining modules of different types in a mixed order.

Resolution

All modules of a certain type must be defined together. For example; the following pseudo-code would cause the runtime error:

DEFINE_MODULE 'A'

DEFINE_MODULE 'B'

DEFINE_MODULE 'A'

DEFINE_MODULE 'B'

This can be corrected by defining the modules as follows:

DEFINE_MODULE 'A'

DEFINE_MODULE 'A'

DEFINE_MODULE 'B'

DEFINE_MODULE 'B'

Note that this does pose a limitation on the use of modules: A module can call another module or be reused, but can not do both. For example, if module type B is defined within module type A, then the following situation occurs:

DEFINE_MODULE 'A' (calls DEFINE_MODULE 'B')

DEFINE_MODULE 'A' (calls DEFINE_MODULE 'B')

This is effectively the same as the original problem:

DEFINE_MODULE 'A'

DEFINE_MODULE 'B'

DEFINE_MODULE 'A'

DEFINE_MODULE 'B'​