If you get a warning message in Control Studio that a module cannot be saved because more function blocks than can be supported are scheduled to run in a device, it is possible that the device's start list entry limit has been exceeded.
A start list entry is created for each instance of a block that runs in a device's overall macrocycle. Devices support a limited number of start list entries. A device's start list entry limit can be exceeded when the Module-driven macrocycle option is selected and blocks from the same device are concurrently assigned to different modules with fast and slow execution rates.
With the Module-driven macrocycle option selected, the macrocycle is set by the module with the fastest scan rate and a multiplier is used for the slower modules. For example, if the fastest module is running at 500 mSec and the slowest at 4 seconds, a multiplier of 8 is used. If both modules contain an AI block from the same device, the start list entry total is 9 (8 start list entries for the AI in the 500 mSec module and one entry for the AI in the 4 second module). Depending upon the device, the start list entry limits can be quickly exceeded in this situation. To avoid this problem, run the device's blocks in modules with similar execution rates.