Hot Swap Sensor Maintenance

Hot swapping involves the immediate exchange or “swap out” of an in-service sensor with a pre-cleaned, pre-calibrated sensor that is ready for duty. It is quick, clean and painless. The old sensor is swapped out on a scheduled service rotation and is returned to the workshop or laboratory for service and calibration, whereupon it too is made ready for its next service interval. This repeated process allows for quick and efficient infield exchanges and facilitates extremely time and cost-effective maintenance of rotating sensors.

This is relatively new, but the simple concept has transformed the way we manage and maintain sensors, resulting in much fewer hours spent cleaning and calibrating sensors, extending service life and improving accuracy. How is all this possible? Consider a traditional installation scheme where a sensor must be connected to the infield analyser. Calibration must be performed on the in situ analyser as this is the only device that has memory and a microprocessor to store calibration data and perform algorithmic correction and conditioning of the sensor signal. As a result, cleaning and calibration regimes tend to be time-consuming and sometimes ineffective due to:

• Working in harsh environments, either climatically or hazardous or both
• Difficult and laborious with operators having to cart cleaning equipment, buckets, beakers, harsh cleaning solutions, rinse water, buffers etc
• Cleaning tends to be rushed and often done improperly or incomplete
• Calibrations tend to be rushed, often not allowing sufficient thermal stability in a sensor and resulting in calibration errors

By contrast, a hot swap regime allows all this work to be done offline in the comfort of the Laboratory or Workshop environment. All this is made possible because a Smart Sensor is a self-contained unit, embedded with an onboard microprocessor and memory that fulfils the job of the analyser. It is able to store calibration data and output a fully compensated signal, and as such, it can be calibrated anywhere offline away from the main analyser. This has a number of benefits from a maintenance point of view and facilitates a whole new way of sensor management.

The challenges of infield calibration are reduced significantly in that:

• Sensors can be batched and cleaned in large numbers, rather than individually, saving a huge amount of time. For example, a group of sensors can be soaked at once in the cleaning solution for extended periods, allowing the solution to do the hard work and properly remove all contaminants.
• Sensors can be batched and calibrated. Batch processing sensors in this way are extremely time efficient and cut calibration times down to about one quarter (reduces time by 75%) compared to infield calibrations.
• Sensors are calibrated in a controlled environment at stable temperatures reducing calibration errors that can occur in the field. They are also at thermal equilibrium in a stable environment which allows rapid calibration times as you are not waiting for a sensor to return to ambient (ie from process temperature) which depending on your process can take a significant amount of time.
• Sensors can be stored in a conditioning solution between uses. This optimises their performance and rejuvenates them in between service shifts. Anecdotal evidence shows an improvement in sensor lifespan of around 30% when a sensor is cared for in this way.
• Lastly, quick connect plugs facilitate seamless plug-n-play to the infield analyser. Nothing needs to be done to the analyser, simply plug the new sensor in and it will be automatically recognised by the analyser.

This service and maintenance regime is highly recommended for users that have:

1. A large number of installation points and expend significant manpower on maintaining sensors
2. Sensors that rapidly foul and require mechanical cleaning
3. Very stringent calibration accuracy and high frequency of calibration
4. High process temperatures or any situation where the sensor requires significant time to reach thermal equilibrium
5. Sensors in remote, difficult to access or hazardous locations
6. Installations in inclement weather
7. Lazy operators   

Sensor Care and Maintenance
Turtle Tough sensors can be cleaned and calibrated offline to facilitate a hot-swapping maintenance regime. To know more about our sensor care and hot-swap maintenance regime go to turtletoughsensors.com/support/maintenance