Another aspect that wasn't mentioned is the fantastic protocols that are now readily available for wireless sensors. These wireless protocols make it very easy for a designer to grab a licensed radio with an off the shelf networking protocol and quickly design a solution that that can run off a coin cell. A few of the protocols are even tailored for wireless sensors and include firmware that can provide wireless sensing without any programming knowledge.
Having installed multiple wireless controls grade applications (10ms) in manufacturing environments. The 2.4gightz bandwidth is so clean that a wireless is more reliable than a wired. Motor servos, spot welding, arc welding don't have harmonics that interfere with this communication. There are segments of the automotive manufacturing sector that are using wireless so trouble free that they forget that it's even there.
I believe that simple "hasn't been done before" logic is preventing its widespread use. Just as with cell phones once you start using it you won't go back and I predict that 10 years from now we'll all be using it.
Rob, Not sure how much wireless communications is susceptible to interference issues. Maybe others more knowledgeable can comment on possible problems. It seems that with most factory environments, it may not be an issue. Perhaps there are specific types of manufacturing, welding as a guess, where communications problems may be a bigger issue.
I didn't realize it was easy to interfere with the communication of wireless devices. Is there a way to secure wireless communication? Sounds like this is not an insignificant problem. I know that a good number of plants are already using wireless devices for at least part of their networks.
Aldo, I agree with you that wireless sensors are not ready yet. We are at the beginning of the evolution of this technology and there are many details to be worked through. What's exciting is the potential impact. Thanks for your comments. Al
Hi, this article is good but I don't think wireless sensors technology is ready to become to a massive use in industrial plants because it is not robust and reliable, there are always sources of noise and interference in factories that may cause malfunctions if the sensor is not good shielded. Another important point I think would help this technology to deploy is the usage of very low power components that dont require periodical battery change.
Al speaks of Outside-the-Box thinking in designing for battery life for long-term-polling sensors. Here's one: Counter Intuitive to saving power, is the idea adding a second transceiver circuit to a sensor.(But wouldn't that use twice as much power-? On the contrary).Where the first transceiver is the primary application for tracking or communication (or whatever your Fav.App,,,) it needs to be ensuredmonths or even years of battery life to poll and report.To accomplish that, we must keep it turned OFF 99.9% of the time, and it will last as long as its shelf life, measured in years.For the other 0.1% of the time, SW awakens it for a 10ms ping, purposed to sense vicinity of a 2nd transceiver, plugged into a nearby AC source. If it wakes up for a "ping" and does not sense its 2nd transceiver partner within range, it knows its been moved outside a pre-selected area (like a geo-fence). Now it comes to full power and reports its location back to owner or police for tracking. This results in five-year battery life on a battery powered tracking device. This was the subject matter of a Start-Up I worked with in 2007.
Ann, The key to sensing aluminum and and steel at the same distance is long range inductive proximity sensors, and specifically technology that Pepperl+ Fuchs calls Reduction Factor 1. sensors offer a special air-core coil system that is precisely adjusted to ensure that target detection is independent of the metal's characteristics. The air-coil system also makes them insensitive to interference from frequency converters or magnetic fields.
Well worth the read for this article. The "Internet of Things" is indeed here and is going to change our lives in big ways that are hard to see now.
I especially like the remarks concerning smart distributed sensors cooperating in a way to create a true smart control system for factories and plants.
Given the use of battery powered devices I would think one notification that would be of interest is remaining battery life. If the environment affects the battery life in some way the system would need to know how much longer the battery could function in supplying the required power. Mere time schedules for replacement might not be adequate.
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