Siemens S7-1200 Operating Instructions Manual page 73

Slot
Here, enter the slot number of the CP in the partner station.
You will find the parameter in the parameter group "General" on the partner CP.
Send buffer
When enabled, the frames are stored in the send buffer (frame memory) of the CP if the
connection is disturbed. Note that the capacity of the frame memory is shared by all
communications partners.
If the option is disabled, even frames for events are only stored in the image memory of the
CP; in other words if there are problems on the connection older values are overwritten by
new values.
Access ID
The access ID of the partner CP is displayed here.
The Access ID (DWORD) is formed from the hexadecimal values of project number, station
number and slot:
Bits 0 to 7: Slot
Bits 8 to 20: Station number
Bits 21 to 31: Project number
CP 1243-7 LTE
Operating Instructions, 01/2015, C79000-G8976-C381-01
4.15 STEP 7 configuration of individual parameters
Configuration and operation
73