Interbus Error (ILIB0004): The number of Interbus devices ... exceeds the maximum of ... .
The number of connectable INTERBUS devices an INTERBUS master can handle, is limited. The maximum value depends on the master type and is specified in the device description.
In your project too many INTERBUS devices are inserted under the INTERBUS master. This includes PCP devices as well as devices that do not support PCP.
The maximum number is mentioned in the error message and can be found in the properties page of the INTERBUS master.
Remedy
Reduce the number of INTERBUS devices in your project.