The Sequencer Implementation StrategyĪt the core, the sequencer is built from three components: Inputs, Outputs & Step Logic. In this tutorial, we will be going over the use cases of a sequencer, how the SQI and SQO instructions are setup as well as a practical example of a sequencer. Although the squencer isn’t something you’d expect to use on a regular basis, it’s an advanced technique which shines in specific applications. It’s a technique which utilizes SQI and SQO instructions in order to create a sequence of events which is based on specific steps & allows the PLC to follow a prescribed sequence of events. Programming a Sequencer in Ladder Logic on a PLC is an advanced skill.