Siemens SIMATIC S7-1500 Function Manual page 318

The warning triangle in the column of the dynamic station resources is displayed because
the sum of the maximum available connection resources of CPU, CP and CM
(= 310 connection resources) exceeds the station limit of 256.
Note
Available connection resources exceeded
STEP 7 signals the exceeding of the station-specific connection resources with a warning.
To make full use of the connection resources from the CPU, CP and CM, either use a CPU
with a higher maximum number of available station-specific connection resources or reduce
the number of communications connections.
②
Module-specific connection resources
The columns of the module-specific connection resources provide information about the use
of resources on the CPUs, CPs and CMs of an automation system:
The display is per module and not per interface.
In the example, the CPU makes a maximum of 128 connection resources available, of which
18 are already in use and 110 still available.
The used resources are divided up as follows:
● 6 resources for HMI communication
● 4 resources for S7 communication
● 8 resources for Open User Communication
Communication
Function Manual, 11/2019, A5E03735815-AH
Connection resources
11.3 Display of the connection resources
317