---
title: "Cycle controller / sequencer"
description: "A cycle controller (or sequencer) programmes the firing pattern of one or more sonic horns — pulse duration, pulse interval, firing sequence across multiple horns, zone grouping, response to plant DCS signals. It can be either a dedicated standalone hardware unit or a subroutine inside the plant PLC or DCS."
canonical_url: "https://sylio.co/glossary/cycle-controller-sequencer"
last_updated: "2026-06-28T02:29:28.220Z"
---

A **cycle controller** (or **sequencer**) programmes the firing pattern of one or more [sonic horns](/glossary/sonic-horn) — pulse duration, pulse interval, firing sequence across multiple horns, zone grouping, response to plant DCS signals. It can be either a dedicated standalone hardware unit or a subroutine inside the plant [PLC](/glossary/plc) or [DCS](/glossary/dcs).

## Programmable parameters

- **Pulse duration** — typically 5–15 s per burst
- **Pulse interval** — typically 3–15 minutes between pulses on the same horn
- **Multi-horn sequencing** — fire one horn at a time to manage compressed-air demand
- **Zone grouping** — separate cycles for hopper, plate area and penthouse zones
- **Response to operator override** — manual fire, manual silence, mode switching
- **Alarm output** — to flag a stuck valve, low air pressure or controller fault

## Standalone vs PLC-integrated

A standalone cycle controller is simple, cheap and adequate for small installations. Larger multi-horn systems benefit from PLC integration with the plant DCS so horn sequencing can respond to operator commands and process conditions in real time.

## Related terms

- [Sonic horn](/glossary/sonic-horn)
- [Solenoid valve](/glossary/solenoid-valve)
- [PLC](/glossary/plc)
- [DCS](/glossary/dcs)