Controls work at three levels
It helps to separate three jobs that are often confused.
- Machine control: the controller on each compressor protects the machine, loads and unloads it, and reports faults and temperatures.
- Station control: a sequencer or master controller decides which compressors run and how they share the load so the plant holds its pressure band.
- Monitoring and data: remote monitoring, trends and alarms show how the system behaves over time and give maintenance an early warning.
Machine controllers
The local controller is the first line of protection. It guards against over-temperature, over-pressure, motor overload and sensor faults, and it sets the loading behaviour of the machine. Knowing which controller and firmware revision is fitted matters when you plan replacements or upgrades.
Sequencing and master control
When several compressors feed one system, each machine acting on its own pressure setting tends to widen the pressure band and run more machines than needed. A sequencer or master controller coordinates them against a single pressure target. Base and trim strategies keep stable loads on some machines and let one machine follow demand, and variable-speed machines are most useful where demand varies, within their usable turndown range.
Monitoring, alarms and trends
Remote monitoring gives visibility of status and alarms without walking to the compressor room. Condition monitoring goes further: it records indicators such as temperatures, pressures, differential pressure across filters and running hours, builds a baseline, and highlights change. Alarms should be rationalised so that the ones raised mean something, and trends should be kept long enough to compare like with like.
Connecting to plant systems
Where the compressed-air system needs to talk to a building management or SCADA system, the point list, signal types and data ownership should be agreed before wiring starts. Operational data also needs a clear boundary: who may read it, who may write to the controller and how remote access is secured.
What to define before choosing controls
- The pressure the process actually needs at the point of use
- The demand profile across shifts, including peaks and idle periods
- The number, size and type of compressors, and any existing controllers
- The alarms and data that maintenance and management will really use
- Who is responsible for the control logic, the network and the data
Frequently asked questions
Do I need a sequencer if I only have two compressors?
Not always, but two machines with independent pressure settings often overlap and waste energy. A simple sequencer or well-set cascade can stabilise pressure, so it is worth reviewing how they interact.
Will a variable-speed compressor fix my pressure fluctuation?
It can help where demand varies, but it will not cure leakage, restricted piping or poor storage. We recommend measuring the system first so the control strategy answers the real cause.
Is remote monitoring only for large plants?
No. Any site where a compressor stoppage is costly can benefit from alerts and trends, provided the alarms are meaningful and someone is responsible for acting on them.
Can you integrate compressor data with our SCADA or BMS?
Integration is possible where the controller supports a suitable interface. We agree the point list, signal types and responsibilities before work starts.
Does connecting compressors to a network create a security risk?
It can if it is done carelessly. Remote access should be limited, authenticated and agreed with your IT or operations team, and ownership of the data should be clear.