How is a sequencing operation typically implemented in ControlLogix?

A sequencing operation in ControlLogix is effectively implemented by using a state machine or Counter Instructions. A state machine is a logical construct that allows the program to transition between different states based on specific conditions or events. This approach is well-suited for sequencing tasks because it provides clear definitions for each state, the criteria for transitioning from one state to another, and the actions to be performed during each state.

Counter Instructions complement this by allowing the program to count events or occurrences that can trigger state changes. This combination enables robust control over complex sequences, as it can manage the flow of operations and ensure that the correct actions are executed as per the designed sequence.

Using mathematical instructions would not directly address the sequencing's operational logic, as their primary use is for arithmetic calculations rather than flow control. Timed logic operations, while they can impose delays or timing constraints, do not inherently manage the states or transitions required for a full sequencing operation. Utilizing global arrays can assist with data storage or management but doesn't inherently provide sequencing capabilities without additional logic to interpret the array data. Thus, the most effective and structured methodology for implementing a sequencing operation in ControlLogix is by employing a state machine along with Counter Instructions.