So Why aren’t Wireless Smart Sensors More Prevalent?
Last week in the San Francisco Bay area two conferences were going on that had significant machine-to-machine content. Connected World, the magazine, sponsors its M2M conference every year and after a more than a decade in the Chicago area it moved to Santa Clara, CA. At the same time ABB’s software arm, Ventyx held its first Ventyx World event at the Westin and Hyatt on Union Square in San Francisco. Obviously Connected World was all about M2M but M2M, mobility and smart systems figured heavily into the Ventyx World agenda as well. With so much attention on M2M/wireless and so much talk about it why haven’t wireless and smart sensors taken over the process control world by storm?
My guess is there are two factors. First: caution - the old manufacturing adage “if it ain’t broke don’t fix it” is still prevalent. Second: Suppliers have failed to establish the incremental cost/benefit ratio users need to justify the investment. Addressing the second will help overcome the first. Suppliers need to show the incremental value of additional data in that most control systems already in use today do an adequate job. One or two basic process measurements allow for sufficient control.
Think about your own home. Most of us have a simple thermostat that regulates the temperature by turning the AC or furnace on as required. If we live in a climate where humidity varies wildly we may have a humidifier which has a simple humidistat built in as well. So with two simple measurements we can control the environmental comfort of our residences. While some commercial buildings may add an airflow sensor to regulate air flow velocity, in our homes we don’t add one or any other sensors, as what we have is adequate.
In industry the same holds true - if we are doing an adequate job of control why invest in more information? What has changed is that we now have instruments that due to semiconductor manufacturing processes can deliver a variety of combined measurements for the same fundamental cost as an older single-purpose instrument. However, if the instrument supplier charges a premium for the additional information can we justify that premium. Also, the cost of moving that information from the measurement point to the decision point needs to be considered. In wired sensor implementation the cost of wiring can often match or even exceed the cost of the sensor or actuator.
Wireless can help by drastically reducing wiring costs. What is needed to drive greater adoption is lower cost tools to use the additional information to control processes better. This means control companies need to shift from selling sensors, actuators and controller and instead deliver process performance. If a vendor told me they could keep my home comfortable year round while lowering my energy bill - all for the same price as a simple programmable thermostat I really would not care if they used one or ten process measurements - only that they delivered on what they promised. Control systems vendors need to change the way they think about what they are selling.