I might have blogged about this before so please bear with me if this sounds familiar, but it's very important. Recently our senior application engineer drafted a story for our quarterly newsletter that highlighted the importance of selecting a proper location for the mounting of a continuous level sensor or inventory monitor. Take a look at the picture here and you'll see his point. In this case the inventory in the silo is monitored using a smart weight & cable sensor. These devices are accurate and very reliable. As you can see in the photo, the weight & cable just barely misses a cross-beam inside the silo. Making sure that you locate the sensor so as not to have obstructions within the path of the sensor is very important.
Let me illustrate this with a story. Several months ago we got a technical support call from a customer of ours that had several smart weight & cable inventory monitors at his facility. The entire system was installed by a systems OEM of ours that we have been doing business with for many years. All was working well except for one silo. The sensor "short-cycled" every time. This means that the weight & cable would drop a few feet and then return to its socketed position. This was mystifying because the material level was far more than just a few feet below the sensor. Well we went through diagnostics and replaced a couple of circuit boards trying to isolate the problem within the sensor. Still the problem persisted. We decided to replace the entire sensor.
Upon return of the problem sensor to our factory we evaluated the unit and found.... no problem! The sensor worked perfectly. In the meantime the new sensor we sent out was installed and.... you guessed it.... it "short cycled" as well. Finally our OEM had one of their service technicians climb the silo (the replacement work was done by end user personnel) and he discovered that the sensor was mounted directly above a cross member inside the silo located just a few feet below the sensor. Gee, what a surprise. Needless to say, once the sensor was relocated slightly it worked perfectly.
It's the location dummy! All's well that end's well and that's ...... the rest of the story.
Joe Lewis
Technorati Tags: sensor location weight & cable sensor silo inventory monitoring
Comments