Can a Pressure Transducer Be Installed in Any Orientation?

Yes, a pressure transducer can usually be installed in any orientation, but changing the mounting position from its factory calibration can affect measurement accuracy.

Engineers and technicians often face installation constraints that require mounting a pressure transducer horizontally, vertically or at an angle. Space limitations, piping configurations or equipment layout can dictate where the instrument must be installed, which raises an important question about whether the mounting position will influence measurement accuracy.

Read this article to learn how pressure transducers measure pressure, how gravity affects the sensing element and how to correct position related errors when the installation orientation differs from the factory calibration.

How do pressure transducers measure pressure?

Pressure transducers measure pressure by detecting movement in a sensing diaphragm and converting that movement into an electrical signal.

When process pressure from air, gas or liquid acts on the diaphragm, the diaphragm flexes slightly. Internal sensing technology detects this movement and converts it into an electrical output signal that monitoring systems and controllers can interpret.

The most common electrical output signals include:

• 4 to 20 mA (milliamps) current output

• 0 to 5 Vdc voltage output

• 0 to 10 Vdc voltage output

• millivolt per volt signals

These signals allow process control systems to monitor pressure conditions continuously and respond to changes in the system.

Does installation orientation affect pressure transducer accuracy?

Yes, installation orientation can affect pressure transducer accuracy because gravity acts on the sensing diaphragm.

Gravity influences the diaphragm and sensing components regardless of how the instrument is installed. When the transducer is mounted in one position, gravity pulls on the diaphragm in a specific direction. If the instrument is installed in another orientation, the direction of gravitational force changes.

For example, a transducer installed horizontally experiences gravitational pull on the sensing element differently than one installed vertically. This shift can slightly change the output signal and create a small measurement offset.

In many applications this change is very small, but in low pressure measurement it can become more noticeable.

Why are position effects more noticeable in low pressure transducers?

Position effects are more noticeable in low pressure transducers because the measurement range is very small.

For pressure transducers like the Ashcroft® S1 Pressure Transducer with a pressure range above 15 psi, the influence of gravity on the sensing element is usually negligible. However, when measuring very small pressures even minor forces can influence the output signal.

Pressure transducers like the Ashcroft® CXLdp with ranges less than or equal to about 5 psi, which is approximately 140 inches of water column (IWC), are generally considered low pressure instruments.

Because of their sensitivity, low pressure transducers are often calibrated at the factory for a specific orientation such as horizontal or vertical installation. The position decision is often based on the application, where the instrument will be installed in the process and the specified pressure range.

What happens if a transducer is installed in a different orientation than its calibration?

Installing a pressure transducer in a different orientation than its factory calibration can create a zero offset that affects measurement accuracy. See Figure 1 for a quick example. 

Figure 1: Transducer orientation comparison example

Customer A uses a pressure transducer calibrated for vertical mounting. When the instrument is installed vertically the output signal reads correctly at 4 mA when zero pressure is applied.

Customer B uses a low-pressure transducer calibrated for vertical mounting but installed it horizontally instead. Because gravity now acts differently on the sensing diaphragm the instrument reading shifts and falls outside the specified accuracy range. This shift is known as a position effect.

How can you correct position related measurement errors?

Position related errors can usually be corrected by zeroing the pressure transducer after installation. Once the instrument is installed in its final orientation, the installer can adjust the zero potentiometer on the transducer. This adjustment removes the offset caused by the position effect.

The process typically includes three steps:

• Install the pressure transducer in its final mounting position

• Apply zero pressure to the system

• Adjust the zero potentiometer if necessary

After this adjustment the instrument will provide accurate measurements in the installed orientation.

In other words, any pressure transducer installed in a different orientation than the factory calibration can usually be zeroed in its final position to eliminate the position effect.

What sensing technology works best for low pressure transducers?

Silicon sensing technologies are generally less sensitive to orientation changes than metal diaphragm sensors.

Low pressure transducers commonly use either metal diaphragm sensors or silicon-based sensing technologies. These technologies differ in size and mass, which influences how gravity affects the sensing element.

Metal diaphragm sensors typically have larger surface mass. Because of this larger mass they can be more susceptible to position effects caused by gravity.

Silicon based sensors are smaller and lighter, which reduces the influence of gravity on the sensing element. This makes them generally less sensitive to orientation changes.

For applications that require highly accurate low-pressure measurement, silicon sensing technologies are often preferred.

Key takeaway: pressure transducer orientation and accuracy

Pressure transducers can usually be installed in any orientation, but installation position can influence accuracy in low pressure applications.

If the installation orientation differs from the factory calibration position the instrument may experience a small zero offset. Fortunately, this position effect can typically be corrected by adjusting the zero setting once the transducer is installed.

Understanding how gravity affects the sensing diaphragm and how sensor technologies respond to orientation helps ensure accurate pressure measurement and reliable system performance.

Ready to learn more?

Now that you understand how pressure transducers measure pressure, how orientation influences the sensing element and how to correct position-related errors, you may still have questions. Take a minute to review additional resources below, or feel free to contact us to speak to a product expert. 

In the meantime, download our guide to learn how to keep your critical environments running efficiently.