In automation terminology, what is an Indexer?

• A. A processor
• B. A positioner
• C. A timer
• D. A sensor

Answer: (B)

Indexing is about moving a load in discrete, repeatable steps to predefined positions. An indexer is the device that performs that stepping motion and holds each position until the next input signal comes in. It translates control pulses or commands into precise increments of motion, advancing to the next stop with each signal and stopping at the programmed position. This makes it ideal for applications where parts must be moved from one exact station to the next in a cycle, rather than driven in a continuous, smooth motion.

This concept differs from a processor, which runs the overall logic and control programs; a timer, which provides fixed time delays; and a sensor, which detects conditions or positions but doesn’t inherently move or position loads. An indexer specifically provides the stepped positioning functionality that moves through a series of indexed positions.