Getting the most out of your Phathom sensor

It’s easy to get great results from your Phathom sensor. Every sensor comes with an electronic manual, a video demo, and an app and USB dongle for calibration, so you can get in the flow as quickly as possible. To help you get going, you’ll find answers to some common questions below.

Setup and calibration

Because Phathom sensors generate and measure light intensity, they’re designed to exclude the effects of ambient light. However, light variations from other sources may need to be excluded or they could skew the readings. Ensure your monitoring system includes a manifold or other covering to maintain a consistent light environment.

As is the case with all sensors, bubbles will affect turbidity measurement because bubbles scatter and reflect light. Set up your Phathom sensor away from sources of aeration.

TSS and turbidity vary at different depths and at different places on the same site, so make sure your Phathom sensor is securely fixed in one place so that it can give you consistent data.

Calibrate your Phathom sensor for TSS monitoring in mg/L by taking reference samples of the water at your site. This relates the sensor’s output to the characteristics of that particular environment. You can create a calibration range by taking samples at higher and lower concentrations of the locally occurring suspended solids. The concentration of the calibration samples can be cross-checked in a laboratory.

Calibrate your Phathom sensor for turbidity monitoring by using an internationally recognised standard like formazin. Using higher and lower concentrations of the standard will create a calibration range.

Cleaning

Unlike single-beam sensors that require constant cleaning, Phathom sensors only need occasional cleaning at most because their multi-beam technology self-compensates for accumulated dirt unless they get completely clogged. Because they’re robust, Phathom sensors can easily be cleaned manually, for example as part of a periodic maintenance programme. They can also be cleaned automatically by fitting a jet attachment connected to a hose supplying an occasional burst of compressed air or water.

Technical detail

Phathom sensors are immersion-style water monitors. They cover the full range of clean to dirty water (0-10 g/L and 0-4000 NTU) so there’s a Phathom for every environment.

Key technical specifications:

  • Connection: directly with 4-20mA, SDI-12 and Modbus RS485
  • Temperature: 0-50 degrees Celsius operating range
  • Pressure: up to 5 bar
  • Required power: 0.25W at 5V for Modbus or SDI-12 only, or 9-32V for 4-20mA and Modbus
  • Wavelength: 880 nm as standard, other wavelengths available

For further details and dimensions, access the data sheets below.

Getting the most out of your Phathom sensor

What are Phathom sensors made of that makes them so robust?

Phathom sensor heads are made from tough single-piece polypropylene. Developed to withstand the high pressures and temperatures of industrial processes and the harsh, abrasive environments of the mining industry, Phathom sensors are far more rugged than glass-and-stainless-steel sensors with their vulnerable lenses. The T-series of Phathom sensors also uses polysulfone for the prongs of the sensor, with stainless steel protection rods alongside them.

What’s the difference between TSS and turbidity?

There’s a lot of confusion about total suspended solids (TSS) and turbidity because they’re different but related. TSS are actual physical particles in the water (like sediment), and turbidity is the effect on light caused by those particles (and anything else that affects light). TSS and turbidity can each be measured independently. However, many other sensors merely use turbidity as a surrogate, indirect measure of TSS, which really just an estimate of TSS. Phathom sensors are different, capable of directly measuring TSS as well as turbidity.

Read more about the difference between TSS and turbidity here.

How do Phathom sensors measure TSS directly?

All Phathom sensors use attenuated light which provides a direct measurement of light absorption by suspended solids in the water. Since 2016, attenuated light has also been accredited by the ISO as a direct measurement of turbidity.

Read more about the difference between TSS and turbidity here.

Why does Phathom’s multi-beam technology produce better results than single-beam sensors? Phathom’s multi-beam sensors provide unrivalled accuracy that single-beam sensors simply can’t match. That’s because the multiple beams of light can be combined to generate ratio-metric algorithms that self-compensate for common sources of measurement error, like contamination or the ageing of components. Because single-beam sensors can’t generate these ratios, they misread measurement errors as something in the water and produce inaccurate and unreliable results.

Read about the multi-beam difference here.

How do I stop light variations from influencing the sensor?

Ensure your monitoring system includes a manifold or other covering to maintain a consistent light environment. Because Phathom sensors generate and measure light intensity, they’re designed to exclude the effects of ambient light. However, light variations from other sources may need to be excluded or they skew the readings.

How do I stop bubbles from influencing the sensor?

Set up your Phathom sensor away from sources of aeration. As is the case with all sensors, bubbles will affect turbidity measurement because bubbles scatter and reflect light.