Pressure sensors / Vacuum sensors

Pressure sensors and vacuum sensors

A pressure sensor measures pressure changes in gasses and liquids by detecting a force and converting that force into a measurable output signal.Pressure sensors are commonly used to monitor line pressure and tank levels in industrial, mobile, and food and beverage applications.

ifm's product range of pressure sensors and vacuum sensor offer different measuring principles, materials, and displays to meet the requirements of different industrial manufacturing plant operations across the United States. For pneumatic applications, ceramic-capacitive measuring cell is complemented by a stainless steel measuring cell with thin-film or thick-film wire strain gauges (series PK, PV, PT) and a piezoresistive measuring technique. ifm

Pressure sensors are resistant to dynamic pressure peaks and guarantee high overload resistance even in the case of extreme pressure peaks that occur for example with fast closing valves.  Electronic pressure sensors can prevent damage or downtime caused by wear and tear of mechanical moving parts, offering a longer lifecycle than traditional sensors that have critical failure points.  Measuring pressure has a wide range of applications from simple monitoring tasks as an on/off switch to precise digital pressure rating measurements. 

Use the “Select By Application” tool to narrow your search for a pressure sensor based on media type, and read more about the underlying measuring principles and technology of a sensor group by accessing the orange “Learn More” button on the product group level.

ifm pressure sensor and vacuum sensors overviews

ifm’s pressure sensors, vacuum sensors, and pressure switches measure relative pressure. Sensors are equipped with a vent that measures atmospheric pressure. The electronics evaluate pressure or vacuum applied to the measuring cell.

With relative pressure sensors, when there is no system pressure or vacuum, the sensor registers a pressure reading of 0. When pressure is applied, the sensor registers a positive pressure. When a vacuum is pulled, the sensor registers a negative pressure.

Typical units of measure for vacuum sensors in the US are inches of mercury (inHg) or pounds per square inch (psi). “Full vacuum” is considered to be -30 inHg or -14.5 psi.

Certain applications, usually for the pharmaceutical, medical, or aerospace industries require a space to be totally evacuated of contaminants. In these cases, a relative vacuum sensor is not repeatable enough. That's because atmospheric pressure changes with the weather and elevation.

Absolute pressure sensors are necessary for these types of applications and ifm does not manufacture absolute sensors.

Pressure/Vacuum sensor applications

• Vacuum sensors are also used in a wide variety of applications spanning almost all industries. Common applications include:
• Grippers that lift and move objects require enough vacuum to ensure the objects are not dropped.
• Palletizing and depalletizing applications in packaging areas of plants
• Automobile windshield installation in assembly plants
• Vacuum furnaces remove air from the heating chamber during operation and therefore prevents oxidation of metal parts which can affect the strength of the metal.
• Pneumatic conveyors transport bulk solids to storage areas using vacuum drawn through piping systems.

Certain applications, usually for the pharmaceutical, medical, or aerospace industries require a space to be totally evacuated of contaminants.

In these cases, a relative vacuum sensor is not repeatable enough, since atmospheric pressure changes with the weather and elevation. Absolute pressure sensors are necessary for these types of applications and ifm does not manufacture absolute sensors.

Vacuum sensors from ifm: Key features

Most ifm pressure sensor families include sensors that measure vacuum. Some measure only vacuum pressure (‑14.5…0 psi) while others measure both negative and positive pressure. These are known as combination pressure sensors.

• Pressure ranges: -14.5…8700 psi depending on the family
• PX, PA, PV, and PM families are blind transmitters without display
• PN, PI, and PE families have a digital display
• PG family has a gauge display
• Outputs include switching, analog, and IO-Link

IO-Link benefits of ifm pressure sensors

Most ifm pressure sensors have been IO-Link enabled for close to a decade, allowing you to increase the amount of process data available to you and to use that data for actionable insights to improve your machine availability.

This technology is plug-and-work with little or no coding required. Simply plug your sensor into an IO-Link master and send the vacuum values to your SCADA, MES, ERP, or CMMS systems for analysis through the IoT port.

This data transfer occurs simultaneously as your PLC is controlling your machine. 

• Sensors and transmitters with integrated evaluation
• Specially for the use in hygienic applications
• Excellent overload protection and long-term stability
• Measuring ranges of -1…600 bar
• Variable process connection using adapters

Pressure sensor basics

Explore the fundamentals of pressure sensing including pressure, various pressure scales, and different features and technologies in today's advances models. 

What is pressure?

Pressure is defined as the amount of force exerted on a specified area. The most common unit of measure in the US is psi (pounds force per square inch). The official SI unit of measure is the Pascal (Pa or Newton per square meter). The bar is another metric unit of measure equal to 100,000 Pa. 

What is the difference between atmospheric, gauge, absolute, and vacuum scales?

Atmospheric pressure is the air pressure exerted upon the earth. It is approximately 14.7 psi at sea level and decreases as elevation increases. The gauge pressure scale uses atmospheric pressure as the zero point and extends above or below for positive or negative (vacuum) pressure. The gauge pressure scale is also known as the relative pressure scale since it is relative to atmospheric pressure.

ifm pressure sensors use the gauge pressure scale. Variants rated at 363 psi and below have a vent that allows the zero point to change as atmospheric pressure changes. This allows the sensor to remain within the accuracy specification. For variants higher than 363 psi, the change in atmospheric pressure is negligible with respect to the accuracy specification.

Absolute pressure is defined without respect to atmospheric pressure. Absolute zero is also known as the point of total vacuum. ifm does not manufacture absolute pressure sensors.

The vacuum scale ranges from the absolute zero pressure point to atmospheric pressure. It is typically expressed as negative pressure in units of inches of mercury (inHg).

How does an industrial pressure sensor from ifm differ from another pressure sensor device?

Industrial pressure sensors from ifm offer a solid state solution as opposed to other pressure detectors on the market. Mechanical pressure switches have moving parts such as pistons and springs that can stick or break. Additionally, ifm industrial pressure sensors and pressure transducers provide pressure measurement in a compact, easy-to-install housing. They can be configured in less than 5 minutes without applied system pressure.

How does IO-Link provide process data from pressure sensors?

IO-Link is the foundation of the fourth industrial revolution referred to as the Industrial Internet of Things. Almost all ifm pressure-sensing instruments have been equipped with IO-Link technology for close to a decade.

This technology allows you to increase the amount of process data available to you. You can then log that data over time for trend analysis. This technology is plug-and-work for whenever you want to harness its power.

Simply plug your sensor into ifm’s IO-Link masters and send your sensor data directly to your SCADA, MES, ERP, or CMMS systems. The analysis through the IoT port won't interfere with your existing PLC structure. 

Other features of ifm pressure sensors

• Pressure ranges from -14.5 to 8700 psi depending on variant.
• Various output signals including discrete ON/OFF, 4…20 mA / 0…10 V analog, and pure digital process values.
• Common industrial and sanitary approvals such as CE, 3A, FDA, and EHEDG.
• Free factory calibration certificates that are downloadable from the website.