Glossary
Controls and ancillaries
Programmable Logic Controller
Also known as PLC, programmable logic controller.
A PLC (Programmable Logic Controller) is a ruggedised industrial computer running programmed control logic, designed for long-life unattended operation in harsh industrial environments. PLCs are the standard control device for most discrete and sequential process-equipment functions, including sonic-horn cycle sequencing.
Sonic-horn / PLC integration patterns
- Dedicated horn PLC — a small PLC running only the cycle-controller logic; simple, easy to commission, isolated from plant-DCS changes
- Plant-PLC integration — sonic-horn sequencing as a subroutine inside an existing plant PLC; allows tighter operator interaction and DCS visibility
- Hybrid — dedicated PLC for the cleaning system with a fieldbus link (Modbus or similar) to the plant control system
Procurement implications
Specifying the PLC integration approach early in the project saves substantial commissioning time. Plants that defer the decision until installation often discover that retrofit integration requires more DCS configuration time than the entire horn-installation work.
Related terms
Related terms
- Distributed Control SystemA DCS is the plant-wide process-automation system with operator workstations, controllers and field-device networks. Sonic horns typically integrate via fieldbus to the existing DCS.
- Cycle controller and sequencerA cycle controller programmes the firing pattern of one or more sonic horns — duration, interval, sequence, zone grouping. Either a dedicated standalone unit or a PLC subroutine.
- Modbus, Profibus and ProfinetModbus, Profibus and Profinet are the three dominant industrial fieldbus protocols. Sonic-horn cycle controllers typically support at least one for DCS integration.