Interbus Error (ILIB0005): The Interbus register length ... exceeds the maximum of ... .
In an INTERBUS system, the process data of each participant is integrated into a register (together with PCP and other data) which is shifted from participant to participant through the ring structure in time with the transmission rate. The size which each module occupies in the INTERBUS register depends on the process data size and the PCP size of the module. The maximum size depends on the master type and is specified in the device description.
In your project, the total amount of data for all participants exceeds the maximum size of the register the INTERBUS master can handle.
The maximum register size is mentioned in the error message and can be found in the properties page of the INTERBUS master.
Remedy
Make sure you use modules in the most "data-efficient" way possible. If possible, replace I/O modules with unused inputs/outputs with "smaller" device variants to save data width in the register.
If this is not possible, reduce the number of devices.