While pressure transmitters and electromechanical switches have been around a long time, modern electronic smart switches empower instrumentation and engineering technicians to work smarter, not harder.
Precise pump control. Did you know that digital smart switches offer fully adjustable dead-band? Dead-band, otherwise known as hysteresis, is the difference between the start and stop point in a control loop. With a mechanical switch, it is very hard for engineers to find the exact dead-band they need for their specific application. On the other hand, an electronic switch enables instrumentation and engineering technicians to set the switch to deactivate at any point above or below the set point. Being able to precisely control the on and off points of the pump or compressor means you can keep the equipment from over-cycling, which minimizes excessive wear and tear.
Reliability. Electromechanical switches may turn on and off several times an hour, and in some cases, several times each minute. This often requires maintenance personnel to check this equipment several times a year to make sure it is still working properly. In the case of an electronic smart switch, there are no moving parts whatsoever. No physical component within that digital switch will wear out, regardless of the fact that it may be switching several times a minute. This offers a huge benefit in terms of longevity and reliability – not just for the digital pressure switch, but for the pump itself.
Safety. A failed mechanical switch can be out in the field for a long time before maintenance checks uncover it is not working as intended. This is why many energy professionals use pressure transmitters; however, there can be a lag in communication with the PLC or distributed control system (DCS). If using a pressure transmitter in a safety-critical application, such as an emergency shutdown, then it is better to have a localized instrument that will get the job done immediately instead of risking the lag in communication to the control center. The best digital pressure sensing instruments available today are more of an engineered hybrid between pressure switches and pressure transmitters. Take for example the One Series smart electronic switch, which is always running self-diagnostics to ensure that it is operating as intended. If the One Series detects a fault, it is reported on the digital display, the setpoint switch will fail-safe, and the 4-20 mA output will read ≤ 3.6 mA, providing remote fault indication per the NAMUR standard, especially important from a safety standpoint.
It is possible to have more precise control over your pumps, and using smart switches not only gives you more control, but can also help extend the life cycle of your pumps, compressors, or other equipment. Integrating smart switches also makes sense for smaller maintenance teams, who are asked to do more with less. If easy-to-install smart, hybrid switch- transmitters can free up maintenance teams to focus on other things, then the impact on day-to-day activities can translate into real savings – especially in terms of time and maintenance dollars.