Parker Hannifin is offering a pneumatic system that, it says, can be used as an alternative to PLCs for managing small or simple pneumatic circuits. The air logic system can also be used in areas where there is no electrical supply or where ATEX compliance is required.

The system (shown above) consists of a series of compact modules that operate in response to the condition of inlet and exhaust signals from upstream pneumatic devices, effectively replicating the operation of electrical switches and relays. They can be used individually or combined in series to provide simple or advanced functions.
 
For example, when used as individual in-line modules, they can provide passive And/Or functions. Alternatively, they can be grouped together and mounted on standard rails, on sub-bases with a common air supply, or in cabinets, to provide active And, Or, Not, Yes and Memory functions. Extra functions are available via user-selectable cascade or common input modes. 
 
The modules plug together quickly and simply, with all inlet and exhaust connections being front mounted, and can be reconfigured easily if the requirements of the application change. For rail- or sub-base-mounted systems, the amount of piping can be halved. Operating pressures are from 3–8 bar at temperatures from -40ºC to +60ºC. The modules have a typical response time of less than 3ms, and an operating life of at least 10 million cycles at 6 bar.
 
The lubrication-free system incorporates pressure test points and includes accessories such as time delays, bleed sensors, solenoid actuators, pressure switch relays and modular sequencers. The sequencers offer an easy method for controlling machines that need to go through a defined set of cycles.
 
“The strength of our air logic products lies in their ability to provide an extremely reliable and efficient method of configuring and controlling pneumatic circuits in applications where an electrical supply is unavailable or where ATEX controls apply,” says Claude Barrabès, Parker’s European air logic product manager. “Typically, these include the chemical, mining, transport and offshore sectors.

“Just as importantly,” he adds, “Parker air logic can be used in equipment such as robotic welders, where high electromagnetic fields can adversely affect electromechanical devices, and also offers a cost-effective alternative to PLC-controlled systems, where our products are far simpler to set up and operate without the need for specialised programming knowledge.”