Load cells are a critical tool for many Western Australian projects, measuring the loads, stresses and forces that impact man made and natural structures.

Whilst strain gauge, hydraulic and other load cells may all measure the same thing, how they output that information can vary. Selecting the right signal format is essential in securing accurate and reliable data.

In this article, we break down the four main load cell outputs and how they could (or couldn’t) work on your site. For more information, contact Monitel.

1. Millivolt (mV/V) Output

This is the most common signal output for strain gauge load cells. It’s a low level, analogue option proportional to the excitation voltage applied (usually around 2 mV/V).

Pros

• Incredibly sensitive and accurate

• Works with most typical data acquisition systems

• Perfect for short cable runs and laboratory work

Cons

• The low voltage signal is prone to electrical interference

• A stable excitation voltage is essential

• Requires significant amplification for success over long cable lengths

How we use it

Monitel consultants opt for a millivolt signal when the logger/unit is located near to the load cell.

2. 4–20 mA Current Loop

In many industries, this is the standard. Instead of voltage, the load cell transmits a current proportional to the load applied. The current sits in the 4 to 20 mA range.

It’s a popular choice for remote field monitoring where sites may be hazardous or hard to access.

Pros

• Great stability over long distances

• Largely immune to voltage drops and electrical interference

• Easy to integrate with remote monitoring systems

Cons

• More costly than most other options

• Signal represents an averaged, less specific force

How we use it

Most WA mining projects are in harsh, remote environments, so our consultants often use this current when monitoring tailings dams and bridge foundations.

3. Vibrating Wire (VW) Frequency

Many load cells use vibrating wire technology that converts force into a frequency. That frequency corresponds to a wire tension altered by the applied load.

• Excellent long term stability

• Highly resistant to harsh climates

• Compatible with long cable runs and geotechnical deployments

Cons

• Only compatible with specialised VW readouts or loggers

• More expensive than a standard strain gauge model

How we use it

In geotechnical settings, long term accuracy is often more important than frequent samples. That’s why our consultants utilise this signal in embankments, tunnels and dams.

4. Digital Outputs (RS-485, Modbus and more)

Digital outputs convert an analogue signal and transmit it via protocols such as RS-485 and Modbus. They are most common in factory settings but are beginning to emerge as a popular choice in field monitoring.

Pros

• Immune to analogue noise

• Easily networked for multi point systems

• Integrates seamlessly with modern loggers

• Precise, complex configuration process

How we use it

Monitel deploys this signal in complex, multi parameter monitoring solutions where load data is networked with other instrumentation.

Geosense and Soil Instruments Output Options

Monitel is proud of our brand and product agnostic approach – we have no allegiance to any one sensor or company. Nonetheless, many of the load cells we use are supplied by Geosense or Soil Instruments. Their configurations include:

• Geosense: Offers strain gauge load cells with mV/V, 4–20 mA, or VW outputs

• Soil Instruments: Well respected for their VW systems with integrated readout options

How Monitel Helps You Find a Signal Output

Our team understands that a one-size-fits-all approach doesn’t work for WA operators.

Whether you’re in the South West or the Pilbara, we’ll assess site conditions, distance to logging equipment, monitoring objectives and regulatory demands to determine the best load cell type and output format. Other considerations include:

• Environmental noise: Electrically noisy sites are best suited to current or frequency outputs.

• Existing systems: We’ll ensure new technology is compatible with your existing dataloggers, telemetry or SCADA.

• Sampling frequency: More dynamic sites may require voltage or digital outputs.

• Project duration: If you’re monitoring long term, we’ll look to stable, low drift technologies like vibrating wire.

Get in Touch and Discuss a Monitoring Solution for Your Site

If you’re unsure which output is best for your load cell monitoring system, our consultants can help you find an ideal solution.

For more information about the price and availability of strain gauge and other load cells, contact Monitel today.

In high stakes industries, the integrity of load data is critical. But engineers and site managers can only be sure their readings are accurate when load cells are well maintained.

Monitel provides installation and maintenance services for strain gauge, hydraulic and other load cells, keeping both premium and affordable units durable and reliable.

This post breaks down the conditions that weaken load cell accuracy and how to maintain a sensor. For more information, contact Monitel.

Why Monitoring Accuracy Matters

Engineers and site managers use load cells and other sensors to inform critical decisions. If readings are out of calibration, it can have serious operational and safety consequences for construction, health and mining operations.

Maintenance schedules and warning systems are also informed by long term trend data. Should signal accuracy drift, those systems could prove inefficient or redundant.

In short: inaccurate sensors create false confidence.

What Causes Load Cell Drift?

There are several internal and external factors that can reduce load cell accuracy over time:

Mechanical Fatigue

Even high precision, robustly built units can deform after many thousands of uses. Just a fractional change can reduce sensitivity and shift data.

Environmental Exposure

Deployment in WA’s regions can leave load cells exposed to volatile temperatures, moisture, dust and chemicals. Without proper installation, all of these can interfere with internal components and data accuracy.

Electrical Noise and Interference

Some models are prone to noise and interference unless they are properly shielded.

Improper Mounting or Use

If a load cell is installed off axis or used beyond its rated capacity, its condition will degrade rapidly. In extreme cases, it won’t be able to gather accurate data even after reinstallation and the asset will be written off.

5 Signs Your Load Cells Could Be Failing

It isn’t always obvious when a sensor is beginning to drift, but those changes could have a catastrophic impact on your data and decision making.

These red flags can help identify failures early:

• Gradual rise above a zero reading when no load is applied

• Inconsistent readings under identical repeat loads

• Excessive noise and fluctuations in output

• Readings misaligned with known reference loads

• Sudden drops in signal strength and communications failures

How to Properly Maintain a Load Cell

Keeping load cells accurate doesn’t require constant replacement or a full overhaul of your monitoring system. Good maintenance practices will extend the lifecycle of your setup.

Regular Calibration

Arrange annual calibration checks for low use systems and more frequent assessments for critical units. In between checks, use simulated loads to verify readings. As a part of our comprehensive load cell services, Monitel consultants provide ongoing calibration support.

Climate and Environmental Protection

Protect units with weatherproof housings and sealed cabling if your installation is exposed. If using a hydraulic load cell, ensure fluid reservoirs and tubing remain properly sealed and clean.

Proper Mounting and Alignment

Always install sensors according to manufacturer guidelines. Pay particular attention to orientation and load application, as misalignment here can introduce side forces that alter readings.

Monitor Readouts or Data Logs

Most data loggers are capable of running automated trend analysis and triggering drift and anomaly alerts. This is useful for remote and hard to access sites.

Shielding and Grounding

These protect strain gauge and vibrating wire load cells from EMI and other noise.

How Monitel Promotes Ongoing Accuracy in Geotechnical Monitoring

Our consultants understand that end to end service gives engineers and site managers confidence in their data. Monitel will ensure your sensors are accurate and calibrated from system design onwards:

• Know your systems are properly selected and installed with installation quality assurance

• Consultants provide ongoing calibration services on and off site

• Track data with our remote access dashboards

• Schedule maintenance as you wish to ensure sensor performance

Enquire Today to Arrange Servicing for Strain Gauge and Other Load Cells

Maintaining a load cell’s value goes beyond installation. Keeping long term data accurate and getting the most out of your investment relies on proper maintenance, monitoring and support.

Monitel consultants can help you devise a strategy that keeps sensors performing to their maximum year on year.

For more information about the price and availability of strain gauge and other load cells, contact Monitel.

Monitoring pore water pressure is central to understanding the integrity of a tailings dam. In WA, tailings safety is strictly regulated and it’s important to gather accurate, reliable data to support your reporting and decision making. For many, a hydraulic piezometer  is the sensor that provides that information.

In this article, we outline how hydraulic piezometers work, why they’re ideal for tailings dam monitoring and how Monitel can design a monitoring system tailored to your site.

What Is a Hydraulic Piezometer?

A hydraulic piezometer measures pore water pressure with a porous ceramic tip and fluid-filled tubing. As water pressure increases, it acts upon a fluid column within the system, with pressure measurements read via a Bourdon gauge or digital pressure sensor at the surface.

Hydraulic piezometers are ideal in circumstances where electric or vibrating wire sensors are unviable. In clay, silts or chemically aggressive environments, the simplicity, responsiveness and versatility makes this sensor a reliable choice. At Monitel, we often use the hydraulic piezometer for groundwater, tailings dam and borewell applications.

Legal Requirements for Tailings Dams

Tailings dams are amongst the most critical structures on a resources site. Elevated pressure within a dam’s walls, foundations or surroundings can lead to seepage, settlement or even structural failure. WA has addressed these dangers with several regulatory frameworks:

• Work Health and Safety (Mines) Regulations 2022

• Mines Safety and Inspection Regulations 1995

• DWER tailings management guidance

These regulations mandate proactive monitoring to identify and act upon tailings dam risks. Hydraulic piezometers provide the data necessary for compliance and ensuring public safety.

Why Hydraulic Piezometers Are Ideal For Tailings Monitoring

Highly-Responsive in Low Permeability Soils

In clay-rich tailings or compact embankments, pore water moves slowly. Whilst that can make accurate monitoring a challenge for many types of sensor, the hydraulic piezometer has no such struggle. It excels in these conditions by transmitting pressure through the de-aired fluid column, ensuring stable and consistent readings in low permeability soils. That makes them suitable for groundwater piezometer applications where electrical sensors suffer from delay and volatility.

Resistant to Electrical Interference

Hydraulic piezometers use mechanical pressure transmission, not in-ground electronics. That means they’re unaffected by electromagnetic interference and can maintain top-performance near high-voltage equipment, pumps and conveyors. On top of that, their immunity to signal noise ensures cleaner data and fewer false readings overall.

High-Performance During Long-Term Use in Corrosive Environments

Tailings and groundwater are notorious for aggressive chemicals that degrade conventional geotechnical sensors. Hydraulic piezometers boast a ceramic tip and chemically inert tubing to protect them against corrosion and long-term degradation. These features extend service life and reduce the frequency of maintenance or replacement.

Surface-Based Readouts

Because the hydraulic piezometer’s sensing element is at ground level, data can be easily accessed via Bourdon pressure gauges or integrated pressure transducers. These are house in lockable, weatherproof enclosures and can be connected to your preferred data logging system.

Monitoring Applications Within a Tailings Safety Program

In a tailings dam, hydraulic piezometers can be installed to monitor:

• Starter wall foundation checks: Assessing pore pressure before and after deposition phases

• Embankment stability analysis: Capturing trends during upstream, downstream or centreline raises

• Beach zone saturation monitoring: Watching for pore pressure buildup during and after deposition

• Post-closure assessments: Ensuring long-term water pressure stability within decommissioned cells

With reliable pore-pressure data, you can support active decision-making around response planning, dewatering requirements and risk mitigation. You also promote compliance with audits and inspections conducted by WA’s various regulatory bodies.

Monitel’s Hydraulic Piezometer Range

At Monitel, we often deploy Soil Instruments’ Hydraulic Piezometer. It operates via a passive, twin‑tube system that transmits pore pressure from a porous ceramic tip deep in the ground to a surface readout station at surface level.

The system is flushable, allowing the removal of trapped air to maintain a “hard” hydraulic circuit. It supports positive pressures up to 2000 kPa and negative pressures down to –50 kPa.

Contact Monitel to See How the Hydraulic Piezometer Can Work on Your Site

Monitel works closely with environmental and resources operators across WA to design, install and maintain tailored piezometer-based monitoring systems. Whether its a hydraulic unit or something else, our team selects the most appropriate sensor for your facility.

Should you need, we also offer remote data logging, secure alert systems and technical reporting assistance to streamline your compliance efforts and provide peace of mind.

For more information, speak with the Monitel team today.

 

Piezometers can prove priceless in tracking pore water pressure in geotechnical and environmental applications. Two of the most common and versatile types are the hydraulic piezometer and the vibrating wire piezometer. Each has it’s own advantages and ideal uses and understanding those differences is the key to designing an effective and accurate monitoring system.

In this guide, we break down how each model works, where they perform best and how Monitel can support ongoing monitoring on your site. For more information, please contact our team.

What Is a Piezometer?

A piezometer is a geotechnical sensor used to measure pore water pressure. Accurate and reliable piezometer data is essential in evaluating slope stability, settlement, seepage and groundwater changes in critical applications like tailings dams, mine pit walls and borehole monitoring.

Piezometer data serves many purposes. You might be looking to prove compliance with WA regulations or are perhaps looking to improve engineering design. Regardless, proper sensor selection can have long term implications for site safety and data quality.

How They Work

They might be in the same “family” of sensors, but the HP and VWP function in two different ways.

Hydraulic Piezometers

A hydraulic piezometer operates with a water-filled system and a porous ceramic tip that allows pore pressure to equalise. Pressure is transferred through hydraulic tubing and into a surface gauge such as a Bourdon gauge or pressure transducer. They are non-electrical at depth, providing stability in chemically aggressive and electrically noisy environments.

Vibrating Wire Piezometers (VWP)

In a VWP, a diaphragm is connected to a tensioned wire. As pore pressure changes, the wire’s vibration frequency shifts – those shifts are then recorded and converted into readable pressure data. These sensors are ideal for automated or remote monitoring and are resistant to electrical interference, making them a popular choice for deep borehole installations and long-term systems.

Key Differences and Comparisons

Feature	Hydraulic Piezometer	Vibrating Wire Piezometer
Power at Depth	No electricity required	Requires electrical readout
Signal Output	Surface-based gauge or 4-20mA	Frequency-based data logger
Best For	Low-permeability soils, corrosive or high EMI zones	Remote monitoring, deep boreholes, long-term use
Sensitivity	Excellent in soft clays or slow-draining soils	Excellent overall, especially for changing pressure conditions
Installation	More labour-intensive (requires filling system)	Easier in complex sensor arrays
Durability	High resistance to corrosion and EMI	Rugged, stable, but less suited to chemical attack

 

Hydraulic or VWP? It Depends on Your Project

When to Choose a Hydraulic Piezometer

• Tailings Dams: In fine-grained, low-permeability zones, hydraulic piezometers provide stable readings where electronic sensors may struggle

• Corrosive Environments: Ceramic tips and non-metallic tubing hold up well in chemically aggressive tailings or groundwater

• High EMI Zones: If your site houses heavy electrical infrastructure (like pumps or conveyors), hydraulic sensors will avoid any signal interference they produce

When to Choose a Vibrating Wire Piezometer

• Deep Borehole Monitoring: VWPs are compact, accurate and can be easily integrated with multi-point borehole systems

• Automated Monitoring: These sensors pair easily with data loggers, solar panels and remote telemetry for real-time insights

• High-Temperature Zones: Monitel stocks high-temperature models designed for buried infrastructure, geothermal environments or tailings with heat build-up

Monitel’s Sensor Range

Hydraulic Piezometer

We stock an HP model designed by Soil Instruments. A flushable, passive sensor, it boasts a ceramic filter tip and twin fluid-filled hydraulic tubing. With an operating range of –50 kPa to 2000 kPa, it can support positive and negative pressure readings and maintains long-term stability in harsh subsurface environments.

You can read more here.

Vibrating Wire Piezometers

Monitel can supply a range of vibrating wire piezometers, each designed to address a unique environmental condition found in Western Australia:

• VWP‑3000 Series: Designed for geotechnical and structural monitoring, with multiple filter options, 0.025 % resolution and long cable signal integrity

• W9 Vibrating Wire Piezometer: A compact, robust sensor built for high-accuracy readings from –50 to 4000 kPa, with built-in temperature compensation and surge protection

• W16 Kompakt Piezometer: A small‑diameter unit (19 mm) ideal for constrained installations, available in pressure ranges up to 1000 kPa with hermetic sealing and thermistor temperature sensi

Monitel’s Approach

At Monitel, we pride ourselves on a technology-agnostic approach to sensor selection. We match our systems to site conditions, reporting requirements and budgets – not brand allegiance. Whether your site suits a hydraulic or vibrating wire model, you can be confident your monitoring system is set up for success.

Our team can also support you with:

• Sensor installation

• Piezometer potting

• Connection to remote data loggers and cloud-based dashboards

• Compliance-ready reporting for mining, civil and environmental projects

Get in Touch Today and Learn More About Groundwater Piezometer Monitoring

If you’re unsure whether your project needs a hydraulic or vibrating wire piezometer, it’s important to seek professional advice. Monitel will review your soil conditions, project scope and monitoring goals to develop an effective and compliant monitoring system.

To speak with our team, please get in touch.