slot 3 empty in rack of s7300

Ziemens

why the slot 3 in the rack of an s7300 plc should be empty? what is the idea behind it? thanks

Like already said, in HW-config Slot 3 is only usable for central extension module IM36x.

At the rack inside your cabinet:

If you have no extension but perhaps you will need one in future, because the Equipment will be increased, it is a good idea to use a dummy module at position "Slot 3". This dummy just connect the bus bar.
If you need the extension later, you just have to remove the cover and insert the extension module.

If you have no extension and you are sure that you will not need one in near future, there is no need to have a spare module in "Slot 3". In this case, you can use the next modul ("Slot 4") at position "Slot 3" next to CPU.

IBN-Service

 

Ziemens

why the slot 3 in the rack of an s7300 plc should be empty? what is the idea behind it? thanks

Like already said, in HW-config Slot 3 is only usable for central extension module IM36x.

At the rack inside your cabinet:

If you have no extension but perhaps you will need one in future, because the Equipment will be increased, it is a good idea to use a dummy module at position "Slot 3". This dummy just connect the bus bar.
If you need the extension later, you just have to remove the cover and insert the extension module.

If you have no extension and you are sure that you will not need one in near future, there is no need to have a spare module in "Slot 3". In this case, you can use the next modul ("Slot 4") at position "Slot 3" next to CPU.

 Hello Ziemens,

In addition to IBN-Service 

go to page 5-10

https://cache.industry.siemens.com/dl/files/415/15390415/att_41918/v1/S7-300_IHB_e.pdf