Module-driven macrocycle

Unlike the user-specified option in which the actual macrocycle is based on one block scan rate for all blocks as well as module scan rates, the Module-driven option bases the actual macrocycle on the scan rates of multiple blocks and module scan rates. With the Module-driven option, the Block Scan Rate selection is enabled for fieldbus blocks allowing users to specify the scan rate for each block individually. For example in a Cascade loop, you would typically configure the blocks in the master loop to execute at a slower rate than the blocks in a slave loop. With the Module-driven option there is no need to coordinate module execution rates with the macrocycle. The system takes the module scan rate, block scan rate, and the macrocycle of the device in which the block executes to determine the macrocycle for the block. This macrocycle is then mapped to a predetermined macrocycle:

Depending upon the configuration, up to four macrocycles can run concurrently on a segment. The macrocycles can be seen in the MacroCycle Viewer application.

With the Module-driven option, all blocks on the segment run only as a fast as the blocks in each module need to be updated; not at the same rate as the fastest module. This is the most efficient option if you have multiple modules that contain blocks running at different scan rates such as Cascade loops.