On a recent Pneutech build, we implemented a prime function across three separate pneumatic stations, all operated from a central control enclosure.
The driver for the change was simple. In a previous situation, a machine had been unintentionally started when someone leaned against a start button. There was no system fault. No component failure. Just an accidental press in a busy working environment.
Rather than treating it as operator error, we addressed it through control design.
Station-by-Station Priming
The system consists of three independent stations. Each station now has its own:
- Prime button
- Start button
- Stop button
There is also a shared Emergency Stop that shuts down the entire system.
The key feature is that each station must be primed individually.
Until the prime button for a specific station is pressed, its start button will not initiate movement. Pressing start alone has no effect. Accidental contact with the green button won’t shift a valve or activate the station.
Once prime is pressed for that station, it becomes ready to run. A visual indicator confirms it’s armed. The operator can then press start to initiate motion. When the station is stopped, it must be deliberately primed again before it can be restarted. In other words, every cycle begins with a conscious two-step action - but only for the station being operated.
Centralised Control, Independent Operation
Although all controls are located in one enclosure, the stations operate independently. Priming Station 1 has no effect on Stations 2 or 3. Each requires its own deliberate input before it can run.
If needed, multiple stations can be primed and operated, but only through intentional action at each set of controls. At any point, the emergency stop overrides everything and shuts down all stations immediately.
Designing for the Real World
In pneumatic systems, unintended starts often occur not because of technical faults, but because of how people physically interact with equipment. Leaning, reaching, working in confined spaces, these are normal behaviours in industrial environments.
By introducing a prime stage ahead of start, the control system no longer relies solely on careful button placement or perfect operator awareness. It introduces an intentional enable step before motion can occur.
It’s a relatively simple addition to the control sequence, but it significantly reduces the likelihood of accidental activation.
Good automation design doesn’t just make machines work. It anticipates how they’ll be used and builds safeguards accordingly.