One measurement is simply not enough. At least, that’s the case in many industrial processes. It’s not about a distrust in equipment, but rather a necessary safeguard. For instance, pH often functions as a key control variable and, additionally, a proxy for product quality. Redundancy reduces the likelihood that one bad measurement drives an incorrect control action or hides an abnormal event. Therefore, in critical process monitoring, redundant measurements are less about convenience and more about risk management.
When a deviation occurs, having two or three independent records helps determine whether the process itself truly drifted or the measurement system did. It also enables better lifecycle planning. Technicians can replace sensors without losing visibility, and teams can schedule maintenance proactively based on drift trends.
Managing Risk with Redundant Measurements
In exothermic applications where incorrect pH measurements directly correlate to hazardous events, engineers rarely treat redundancy as optional. For instance, in chemical application process lines, you will often find triple redundancy as a standard of practice. Due to the potentially volatile nature of these applications, in which one incorrect reading can be a catalyst for a hazardous event, redundancy is a necessary caution. If two or three sensors that typically track closely begin to diverge, systems can flag a diagnostic alert before the deviation becomes a batch problem, or worse, a safety issue. With three of the same model sensors in a line, their measurements are stringently monitored for comparative accuracy.
Maintaining Compliance with Redundancy
Another reason operations may insist on redundancy is maintaining compliance. Applications following municipal permitted outfall guidelines may want to ensure their effluent remains in compliance to avoid potential fines or harm to the local environment. Redundancy in these cases protects both operations and compliance documentation. Having multiple measurement references supports cross-checks, documented drift detection, and maintenance actions taken based on objective criteria rather than operator judgment alone.
Similar reasons for redundancy are found in hygienic applications as well, in which methods of verification are strictly employed. Meeting the standards of the United States Pharmacopoeia and other governing bodies of therapeutic/pharmaceutical products often requires such redundancy and additional verification methods as a standard of practice.
Redundancy as a Standard
Even for non-exothermic or permitted applications, redundancy may just be a standard of practice. For heavy applications that see shortened sensor lifespans due to frequent buildup or other degradations, redundancy is employed as an additional verification of general sensor ware. Plants adopt redundancy not because they expect constant failures, but because the consequence of one undetected failure can be expensive or dangerous. Ideal redundant setups are paired with clear standards of operations. Knowing how to interpret measurement trends in your process and knowing your sensor is the best place to start.
If redundancy is common practice in your application, and you’re curious about M4 Knick’s experience with redundant measurements, reach out to one of our experts. Or, grab a front row seat to our solutions by scheduling a training. We’re always eager to find the best solution, no matter your process.