In this episode of our webinar series on web guiding fundamentals, we dive into the critical role of sensors in web guiding systems. Learn about various sensor terminologies such as range, resolution, accuracy, and linearity, and understand the importance of accurate measurement for effective control. We discuss different sensor technologies including infrared, optical, and ultrasonic, and explore the challenges they face including issues with temperature drift and material properties. Discover why precise sensing is essential for guiding performance in web handling applications.
00:00 Introduction to Web Guiding Sensors
00:21 Key Sensor Terminologies
00:45 Challenges with Ultrasonic Sensors
01:09 Importance of Sensor Characteristics - Range
01:39 Resolution
01:59 Accuracy
02:17 Linearity
02:52 Types of Sensors and Their Applications
04:03 Material Dependency and Calibration
04:22 Overview of Advanced Sensor Technologies
Transcript
Show full transcript (725 words)
[Music] One of the most important parts of a webg guiding system is the sensor. It is important because what you can't measure, you can't control. If you have a poor sensor and you're not able to measure the position properly, then there's no way that we can get the accuracy that we need. In terms of sensor terminologies, range, resolution, accuracy, linearity, those are some things that you would see.
type of sensors, infrared, optical, ultrasonic, air type of things that you're trying to look for in terms of web position. Are you trying to look at edge of a web? Are you trying to look for a line on the web or a contrasting feature on the web? How fast can the sensor measure?
Older ultrasonic sensors have issues with past line changes. You can't have the web too close to the ultrasonic emitter because it might reflect the sound waves in a way that doesn't provide an accurate measurement. And then temperature drift. Again, ultrasonic sensors can have issues with temperature drift when we have the P2 electric crystal frequency changes.
And then what kind of a signal output that you get from the sensor. Range of a sensor is the maximum lateral displacement the sensor can measure. Most often for web guiding applications, range is not that important just because of the fact that you're controlling. You're going to bring it in.
But it does becomes critical when you have web width changes and things like that. Most often range is like how much change in the lateral position that you can measure with the sensor. Resolution is the minimum lateral position change that the sensor can see. So if you want to guide a web to 5,000 of inch, then you better have a a sensor that can have 4x or 2x higher resolution than the guiding accuracy.
Accuracy is an indication of how close the sensor measurement is to the real measurement. This becomes important for certain types of sensors affected by materials. Material properties like opacity, porocity and things like that. This is an important characteristic of a sensor.
Linearity is like what how consistent is your measurement with respect to the actual position across the entire range of the sensor. In terms of sensing, why is it important? Some sensors have issues with material properties like opacity, porocity or reflectivity or they may be affected by environmental issues such as air flow, temperature changes or vacuum. So if we can't measure, we can't control.
That's why sensing is an important part of guiding performance. Most often you would see these type of sensors we refer to as opposing beam or fork style or horseshoe style. There are lots of different names for it. Basically how this works is you have one arm emitting a certain type of signal and the other arm receiving that signal and then the web that goes in between blocks it.
It's a simple technology work sensing principle and it works well for a lot of different cases. The problem happens whenever depending upon this type of sensor signal that you have if the web allows that signal to leak through when it's blocked by the web that's where the pro problem occurs. We talked about linearity resolution range all of those things are affected by this kind of sensor. This sensing signal can be air, optical like visible light, infrared lights, or even UV light.
It could also be sound like ultrasonic. It really doesn't matter. And then whether this material is opaque or porous to that signal is what matters in terms of how well you can guide. Often manufacturers recommend different sensors for different materials and conditions.
So you will have a plethora of sensing technologies out there. Like I said, the main disadvantage is material dependent gain change occurs and then requires calibration if you want to get a really good guiding performance. There are other sensor technologies out there like ours which are not affected by material properties and some of the environmental conditions. I'm not going to go into detail about our sensor technology here but just give you a quick overview.
is basically a high accuracy direct measurement or absolute measurement. Our resolution does not depend upon the range and it can work with any material. [Music]