Everyone’s application is different, requiring a wide range of instrumentation for measuring and monitoring. Luckily, there’s a product available for almost everyone now, especially in the pressure switches market. But how do you know what pressure switch is right for your process?
There are mechanical pressure switches and electronic pressure switches in a variety of materials and models available today. During my time working in the pressure measurement industry, I have often heard customers ask which they should use for their specific application.
In this article, I will focus on electronic switches and in what situations they can be used instead of mechanical switches.
But first, let’s discuss what an electronic pressure switch is and how it works.
How Does an Electronic Pressure Switch Work?
An electronic pressure switch is a pressure sensing instrument, which uses a pressure sensor (transducer) as well as conditioning electronics that can be configured to provide a switch output (“open” or “close” circuit) using either a relay or NPN/PNP output.
Electronic pressure switches can also include an LED/LCD local display with push buttons to custom configure the outputs. An electronic pressure switch can also be offered with an analog output (e.g., 4-20 mA or voltage output). In many cases, your application will dictate its use, be it a process, industrial or OEM application.
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.
Electronic pressure switches differ from mechanical switches in several ways. First, they require a power supply (DC voltage) to function and operate, which may or may not be an option for an end user depending on their application.
Also, options can include local display with buttons to configure the unit, which can also allow the user to field program them with no additional instrumentation to make the adjustments.
While a mechanical switch will require a secondary, more accurate instrument to ensure its set point has been calibrated adequately. As a rule of thumb, electronic pressure switches customarily cost more than their mechanical counterparts.
So, when would you need an electronic switch vs. mechanical?
When Would You Use an Electronic Switch?
As previously stated, the pressure switch you should use ultimately depends on your application. Electronic switches are generally used on industrial, OEM or process type applications for high/low alarms, control, pressure monitoring and/or automation. They are also commonly used in conjunction with PLCs and other building control devices.
Electronic switches also tend to be more accurate and repeatable than mechanical switches making them ideal for applications where accuracy is of the utmost importance.
Electronic pressure switches have a longer lifespan when compared to mechanical switches. They can sustain a larger number of pressure cycles because they are built with fewer moving parts, making for less wear and tear to the diaphragm.
In an electronic pressure switch, the diaphragm of the pressure sensor is essentially the only moving part. Mechanical switches have springs, pistons and other moving parts, which can cause more wear and tear over time, resulting in a shorter lifespan for the switch.
Here are some other benefits of using an electronic pressure switch:
- LCD/LED local display
- Programmable in the field
- Easy to use
- Plug-and-play setup with no additional measurement devices needed
- Can program a timer/delay/hysteresis
Mechanical switches are used as pass-through devices. They are commonly used in applications that use AC voltages, where an end user may not have the ability to provide a power source to an electronic pressure switch.
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.
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.
Note what the case material enclosure is made of. Enclosure material can play a major part in the cost or quality of the electronic pressure switch depending on how exotic or common the material is.
Typical weather-proof ratings in the industry include either IP66 or IP67 rated enclosures making them suitable for applications where they may be subject to rain or snow. At Ashcroft, ours are made from high-quality ABS plastic/polycarbonate or nickel-plated aluminum.
Other factors include the types or amounts of outputs, the static accuracy of the switch and whether it includes communication protocols (e.g., HART, IO-Link, etc.) or other diagnostic/troubleshooting tools. Some electronic switches even have Bluetooth connections!
The more bells and whistles on your switch, the more expensive it will be. It depends on your application if you really need all the extra accoutrements, but for most processes, you can get away with a more budget-friendly and simple option.
A quality switch will also have general safety approvals/listings such as UL and CE in Europe. These switches meet certain electronic criteria, can help prevent radio frequency interference and are lead-free.
Another feature that makes a quality electronic pressure switch is temperature compensation. This is the measure for counteracting/correcting an undesired temperature effect, where it ideally eliminates the effects of temperature on the sensor.
The resolution of the display and how many digits it can display (to what decimal place) should also be considered when looking for a high-quality electronic pressure switch.
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.
Ashcroft also offers the GC55, 2274, GC30 and GC31 electronic switches and digital gauges 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.
We don’t like to pressure you, but we have more information.
Now you should understand the situations in which you would need to use an electronic pressure switch over mechanical, as well as what to look for when shopping for the right electronic switch for you.
If you want to learn more about pressure switches, feel free to visit our website and view any of our helpful white papers, webinars or guides in our resource center.
You can also contact us today to talk to one of our industry experts and get all of your questions answered.
