‘Smart sensors’ can play an important role in improving reliability and delivering cost-efficiency, says David Stevens, Technical Authority and Skills Competence Manager for AVT Reliability®. Here, he outlines the value of smart sensors as part of a digital condition monitoring programme.
Reliability managers looking to embed digital condition monitoring (CM) in their operations should consider the capabilities of the technological tools currently on the market, to ensure they get the best return on investment.
The selection of sensors – the device fixed to a rotating machine to take measurements such as vibration and temperature – is a very good place to start.
Limitations of fixed sensors
There are fixed sensors on the market with low price tags, but they offer only a basic level of monitoring, usually aligned to ISO standards for overall vibration levels. These sensors allow little, if any, user intervention or configurability.
In many cases vibration levels are indicated on a basic red, amber, or green ‘traffic light’ system, which has obvious limitations. An operative must be physically in the vicinity to see the alert and cannot properly establish what the issue might be, as there is no data to analyse.
Additionally, the sensor might be configured to take a reading every week, day or hour, so on a machine operating a batch process it could be taking readings when the machine is not operational.
An advanced ‘smart sensor’ with a cloud-based CM system such as Machine Sentry, can overcome these drawbacks and deliver:
• Configurability
• Detailed analysis
• High data storage capability
• Accessibility and hazard limitation
Configurability
A smart sensor has inbuilt configurable features – log frequency, running detection and wake frequency – which enable it both to collect a full set of triaxial vibration readings after a pre-determined time period, and take readings only when the machine is running. This is particularly valuable for batch process applications.
Detailed data analysis
The cloud-based CM system can be configured via the handheld device to a portal, which uses component templates with predefined vibration measurements.
This can facilitate different frequency ranges and lines of resolution for vibration measurements, depending on the rotational speeds of the components. While many sensors only work between 10Hz and 1kHz, a smart sensor can be configured to take readings up to 5.5kHz, delivering more information at a far greater range and enabling a more tailored CM solution. It can measure the components’ surface temperature – particularly useful for continuously running machines.
One of the major drawbacks of a pen and paper approach to asset management is that readings might be taken but never used to inform a maintenance plan.
Digital data collection enables up to 5,000 readings to be stored securely in the cloud. An automated diagnostic assistant (ADA) provides real-time analysis, identifies impending problems, issues an alert and suggests pre-emptive action to avoid unscheduled downtime. This information can be accessed by any authorised personnel from their laptop, from any location.
Enhanced accessibility and safety
A smart sensor can provide accessibility to hard-to-reach assets such as gearboxes on agitator drive units, or those in hazardous environments, while remote data collection via Bluetooth. from, for example, an offloading pump or a solvent pump, removes the need for any operator to be in the vicinity.
Cost benefit analysis
One large chemical company saved £252,320 over 12 months by employing smart sensors in conjunction with the Machine Sentry. system, planning their maintenance instead of letting critical assets run to failure. This illustrates how smart sensors and digital data collection can offer improved reliability and productivity, as well as swift return on investment and ongoing cost benefits.
www.avtreliability.com | david.stevens@avtreliability.com t: 0161 486 3737