While programmable logic controllers (PLCs) like Logo and Pico offer reliable and cost-effective pneumatic circuit control in environments with electricity, what happens when power isn’t available or desired? In hazardous locations, or situations demanding non-electrical solutions, air logic provides a robust alternative.
Decades ago, air logic was the sole method for controlling compressed air applications. Today, it remains a viable option for modern applications needing electricity-free operation. Commercially available air logic elements empower the design of pneumatic circuits relying solely on compressed air.
Here’s a look at some key air logic components:
* **OR Gate:** This gate outputs a continuous control signal when either of its two input air signals is present. It’s ideal for sequencing pneumatic operations that shouldn’t begin until another is complete.
* **AND Gate:** This gate outputs a signal only when both of its two input air signals are present. It’s useful for sequencing operations that require multiple conditions to be met.
* **NOT Gate:** This gate continuously sends an output signal when an input signal is absent. It’s often used to prevent a sequence from starting until another action finishes.
* **PULSE Valve:** This device delivers a momentary output signal to trigger a sequence. The signal drops after a set time, simplifying control and preventing conflicting control air issues caused by improper pneumatic circuit design.
* **TIMER:** These devices either generate an output signal for a specific duration or delay an output signal for a defined period upon receiving an input signal.
* **INDICATOR:** These provide visual confirmation of compressed air presence. They may change color or use a pop-up pin. While pressure gauges work, indicators offer visible confirmation from a distance.
* **POSITION SENSORS:** These sensors generate an output signal based on airflow interruption or continuity, triggered by an object’s position.
These represent just a fraction of commercially available air logic components. They enable the construction of intricate air control circuits.
**Important Caution:** Compressing air generates water and introduces contaminants into the air lines. This poses a significant threat to downstream components, including air logic devices. For reliable operation, ensuring clean, dry air supply is crucial. Neglecting air quality guarantees functional failures in air logic control circuits.