Hydraulic vs Strain Gauge Load Cells: Which Is Best for Your Site?

Selecting the right type of load cell boils down to 4 key factors:

• The site’s environment

• Performance requirements for the project

• Your data handling preferences

• The length of the monitoring period

Both strain gauge and hydraulic load cells offer reliable and accurate measurements, but they fit differently into the above criteria. This comparison unpacks the differences in these two technologies to assist you in making an informed monitoring decision.

For more information or to enquire about sensor installation, contact Monitel today.

What Are Strain Gauge Load Cells?

Strain gauge load cells measure force with electrical resistance. As a load is applied to the cell, an internal steel or aluminium element will deform, changing the resistance in the attached strain gauge(s). Wheatstone bridge circuits convert these changes into electrical signals that are representative of the applied load.

Strain gauge load cells are a sensor known for their high sensitivity, compact design and compatibility with most typical data logging systems.

What Are Hydraulic Load Cells?

Hydraulic load cells have a different working mechanism, using fluid pressure to measure the force of an applied load. An internal diaphragm compresses, moving fluid into a pressure transducer. The resulting pressure change corresponds to the force applied the load. Because there are no electrical components at the sensing point, hydraulic load cells are ideal for:

• Remote environments

• Sites in harsh or dangerous climates

• Long term deployments on powerless sites

• Areas with significant EMI

How They’re Different

Installation

Strain Gauge:

• Requires wiring, connectors and robust shielding

• Must be carefully installed to avoid moisture damage

• The precision required can make installation a lengthy process

Hydraulic:

• No electrical components at the sensing point

• Simple installation, often quicker on site

• Tubing to the transducer must be protected

Our thoughts: Whilst strain gauge systems might offer greater flexibility and precision, hydraulic solutions are faster and cheaper to install on remote or inaccessible sites.

Measurement Precision

Strain Gauge:

• Extremely sensitive with high resolution

• Well suited to dynamic measurements and short term tests

• When properly installed, can be accurate down to millivolt range

Hydraulic:

• Incredibly stable under static conditions

• Can experience minor hysteresis depending on fluid type

• Precision can vary in dynamic conditions

Our thoughts: For a fast, high resolution response, a strain gauge load cell is the best choice.

Electrical Interference and Harsh Environments

Strain Gauge:

• Can be vulnerable to EMI, especially near manufacturing areas

• Requires shielding and careful grounding to negate excessive interference

Hydraulic:

• Immune to EMI as it utilises a mechanical sensing mechanism

• Ideal for high voltage zones or electrically noisy environments

Our thoughts: If your site is in a harsh or electrically active area, a hydraulic load cell is the safest choice.

Long-Term Stability and Maintenance

Strain Gauge:

• Typically stable but can be affected by corrosion, cable damage and signal drift as the monitoring period progresses

• Requires regular inspection of connectors and seals to ensure accuracy

Hydraulic:

• Very stable in static load measurement

• Fewer electronic parts reduce the risk of long term failure

• Must be regularly monitored for fluid leaks or temperature effects, which can impact accuracy

Our thoughts: If you are designing a long term monitoring system, a hydraulic sensor’s accuracy and minimal maintenance requirements make it a suitable choice.

A Quick Guide for Common WA Scenarios

Our consultants have a deep knowledge of Western Australia’s regulatory and environmental conditions and use that understanding to create effective, efficient monitoring solutions.

Tailoring Systems Based on Site Requirements

When selecting a load cell type, we consider:

• Data Frequency – Strain gauges are best when forces are changing rapidly

• Environment – If the site is remote or EMI prone, a hydraulic cell is best

• Power Access – No power? Hydraulic is your only option

• Longevity vs Agility – Strain gauges might be more agile, but they’ll need more maintenance over time

Monitel will assess site conditions to determine which technology is most suitable and advise you of an appropriate monitoring plan.

Product Agnostic Approach

At Monitel, we pride ourselves on taking a product and brand agnostic approach. We are not tied to any one supplier and instead work with a range of load cell models and attachments to create the most compatible and lasting solution for each site.

Our focus is on accurate data and practical installation, not margins and markups. You’ll never be sold equipment you don’t need and will always be able to upgrade or scale in time.

Get in Touch and Reap the Rewards of a Tailored Monitoring System

If you’re unsure as to whether a hydraulic, strain gauge or other load cell sensor best suits your project, Monitel is here to help.

For more information about the application and price of a hydraulic or strain gauge load cell, contact the Monitel office.