When Should You Use an Electronic Pressure Switch?

This blog was originally published on August 2, 2021, and updated on October 30, 2024.

In most industries, the need to maintain accurate pressure levels is important to ensure safety and efficiency. However, when it comes to selecting the appropriate pressure switch for a specific application, the challenge is understanding all the options available and finding the right one for your specific needs.

During my time working in the pressure measurement industry, and specifically with Ashcroft, a leader in pressure instrumentation, I am often asked when an electronic pressure switch (also referred to as a digital pressure switch) is the better option than a mechanical switch. Of course, the answer depends on the application.

In this article, you will learn how an electronic pressure switch works and some scenarios when electronic has advantages over mechanical options. 

 How does an electronic pressure switch work?

A digital pressure switch uses a pressure sensor, also known as a transducer, to detect changes in pressure and convert these changes into an electrical signal. The signal is processed electronically and can be configured to open or close a circuit using either a relay, an electrically operated switch or NPN/PNP output, which are types of transistor outputs.

The LED or LCD local display provides a visual reading of the pressure and the versatile outputs can be configured for a wide range of process, industrial or OEM applications.

Digital pressure switches offer an optional analog output, such as a 4-20 mA current loop or a voltage output, which provides a continuous signal proportional to the pressure level. The analog output is particularly useful in applications where precise monitoring and control are required.

Figure 1: Components of a Digital Pressure Switch. 

How a digital pressure switch differs from a mechanical pressure switch.

Electronic pressure switches differ from mechanical switches in several ways. 

• Requires Power Supply (DC Voltage) to Function. The power supply enables these instruments to provide consistent and reliable operation, though may not be suitable for all applications.
• Local Display with Configuration Buttons: Allows users to program the unit in the field without additional instruments, enhancing ease of use and flexibility.
• Higher Cost Compared to Mechanical Switches. Offers advanced features and greater accuracy, justifying the investment for applications requiring high accuracy.

While electronic pressure switches may require a power supply and come at a higher cost, their ability to be programmed and ease of use make them a valuable choice for applications demanding adaptability. Mechanical switches, on the other hand, require a secondary, more accurate instrument to ensure its set point has been calibrated adequately. 

When would you use an electronic pressure switch?

The choice to use an electronic pressure switch is often dictated by the specific requirements of the application. These switches are highly adaptable and can be employed in various settings, including process industries, industrial environments, and Original Equipment Manufacturer (OEM) applications.

Whether it's for maintaining optimal pressure in a manufacturing process, ensuring safety in an industrial setup, or integrating into a complex OEM system, electronic pressure switches offer the flexibility and precision needed to meet diverse operational demands. You can find electronic pressure switches used on hydraulic presses, tire press vulcanization, water/wastewater pressure control, refrigerant/ammonia-based cooling systems, alarms, control and pressure monitoring.

They also work well for level monitoring, such as tank-level applications where the switch sends a signal when the tank is getting full or low to turn a pump on or off via an analog output. They are also commonly used in conjunction with PLCs and other building control devices.

Figure 2. Where Electronic Pressure Switches are Used.

Benefits of using electronic pressure switches.

Electronic pressure switches offer several advantages over mechanical switches, making them a preferred choice in applications where precision and durability are critical. These switches are known for their accuracy and repeatability, which are essential in environments where precise pressure control is paramount. Additionally, electronic pressure switches boast a longer lifespan due to their construction with fewer moving parts, reducing wear and tear on components like the diaphragm.

Key benefits of electronic pressure switches

• LCD/LED local display for easy monitoring
  
  
• Field programmability for versatile application
  
  
• User-friendly operation
  
  
• Plug-and-play setup without the need for additional measurement devices
  
  
• Capability to program timers, delays, and hysteresis   

Mechanical switches have limits for where they can be set in the ranges and typically have fixed reset points, commonly known as a dead band, while electronic switches can be programmed to set and reset practically anywhere in the range of the device.

The bottom line is the choice between electronic and mechanical pressure switches depends on the specific needs of the application. Electronic switches provide enhanced accuracy, longevity, and flexibility, making them suitable for a wide range of industrial and process applications.

What makes a quality electronic pressure switch?

Now that you know more about electronic switches and when they should be used, let’s look into what makes a high-quality switch so you know what to look for when shopping around.

1.  Material of Case Enclosure: The choice of material for the case enclosure can greatly affect both the cost and quality of the electronic pressure switch. Materials can be rare or commonly used, influencing the overall expense.
   
   
2. Weatherproof Ratings: Industry-standard ratings like IP66 or IP67 ensure enclosures are suitable for harsh conditions such as rain or snow. Ashcroft uses high-quality materials like ABS plastic/polycarbonate or nickel-plated aluminum for their enclosures.
   
   
3. Outputs and Features: You will want to consider the types and number of outputs available on the switch, and also check for support of communication protocols. 
   
   
4. Cost vs. Features: More features typically increase the cost of the switch. Before you make a purchase, you will want to evaluate if all features are necessary for your application to avoid unnecessary expenses.
   
   
5. Safety Certifications: Look for general safety certifications like UL and CE in Europe. These certifications ensure compliance with electronic standards, prevent radio frequency interference, and confirm the product is lead-free.
   
   
6. Temperature Compensation: This feature is crucial for counteracting unwanted temperature effects on the sensor and helps maintain accuracy by reducing temperature impact. 
   
   
7. Display Resolution: Finally, consider the resolution of the display and the number of digits it can show, including decimal places, for precise readings.

Ashcroft recommended electronic pressure switches.

I recently spoke with a customer whose application was in a lab-like setting and was considering an electronic pressure switch. The customer essentially needed something more precise and a set point that required a much lower dead band than what he was able to achieve with his mechanical switch. I asked him if he could provide a power source to which he replied yes, so I recommended Ashcroft’s GC35 Electronic Pressure Switch.

The GC35 is an affordable switch with a programmable switch setting and analog scaling, simple push-button operation, and a min./max. feature to record low- and high-pressure events. Its GloBand™ display provides 360-degree visibility and it’s made from stainless steel wetted materials in a rugged aluminum housing.

Figure 3. Ashcroft® GC35 Electronic Pressure Switch. 

Ashcroft also offers the GC30, GC31, GC55 electronic switches and 2274 digital gauge with options for switch output to help keep your process running smoothly. These are just some of the many electronic switches available on the market today, so make sure you do your due diligence and research what would work best for your application.

Ready to learn more about pressure switches?

Now that you understand when you may choose an electronic pressure switch over a mechanical one, and what to look for when purchasing the right switch for you, here are a few related articles that can provide answers to common switch-related questions. 

• Pressure Switch Basics
• Choosing a Pressure Switch: 9 Factors to Consider 
• Class and Division Codes on Explosion-Proof Pressure Switches 
• What is SIL Certification for Pressure Switches?

You can also contact us today to talk to one of our industry experts and get all of your questions answered. In the meantime, feel free to download our guide to learn about HVAC/R applications for switches.