Subslots
Subslots define the internal addressing structure inside a module.
Each subslot provides the position where a submodule can be placed, enabling the PLC to access cyclic and acyclic data correctly.
What subslots represent
Subslots are internal positions inside a module.
Define the logical address of the plugged submodule.
Determines how the PLC references cyclic and acyclic data.
Must contain at least one submodule.
Ensure only submodules assigned to a subslot become part of the PROFINET device.
Subslot numbering
Subslot 0x0000 is not recommended for use according to the GSDML specification.
Additional subslots are added in sequential order.
Currently, a module can have up to 10 subslots.
Use consistent numbering patterns across similar modules to maintain a clear device structure.
Plugging rules for subslots
Plugging rules define which submodules are allowed or required in each subslot.
Plugging rule | Meaning | Slot behavior |
|---|---|---|
Allowed in | The submodule may occupy the subslot. | The subslot may contain multiple submodules marked as Allowed in or Used in. |
Used in | The submodule occupies the subslot by default. | The subslot may also contain submodules marked . |
Fixed in | The submodule is permanently assigned to the subslot. | Virtual submodules always use Fixed in. No other submodule can be added. |
Importance of subslot assignment
Correct subslot assignment affects:
Where each submodule appears in the engineering tool’s device tree
Where cyclic input data is exposed
Where cyclic output data is exposed
How acyclic records are mapped in the device model
The structure of the generated GSDML file