The IODDTs are predefined by the manufacturer; they contain input/output language objects belonging to the channel of an application-specific module.
INTERBUS communication using the modules TSX IBY 100 and TSX IBX 100 has three associated IODDTs:
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T_COM_STS_GEN which is applicable to all the communication protocols,
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T_COM_IBS_128 specific to INTERBUS communication where the number of configured input/output words is between 32 and 128,
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T_COM_IBS_242 specific to INTERBUS communication where the number of configured input/output words is 242.
NOTE: IODDT variables can be created in two different ways:
Types of language objects
There is, in each IODDT, a group of language objects that enables them to be commanded and their operations to be verified.
There are two types of language objects:
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implicit exchange objects, which are automatically exchanged at each full cycle of the task associated with the module,
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explicit exchange objects, which are exchanged when requested by the application, using the explicit exchange instructions.
Implicit exchanges concern module status, communication signals, slaves, etc.
Explicit exchanges enable module parameters to be set and diagnostics to be performed.
