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Learn about Automationdirect's Fiber Optic Sensors, when to use one and how to choose the one that is right for your application.
Fiber optic sensors are great for those times when you have a tight space where a regular photo optic sensor won’t fit because with the fiber optic sensor you only need enough room for the fiber optic sensor head – the electronics can be placed away from the active area where you have more room to mount it. Or maybe you have a small opening that you need to be able to sense through or maybe you just need to remote the electronics due to vibration, temperature. And one of the best places to use Fiber Optic Sensors is in environments with lots of electrical noise. Near Variable Frequency Drives, or power lines for example because you can put the fiber optic head near the noise and then remote the sensor electronics away from that noise, maybe even in a shielded cabinet. And since the Fiber optic cable isn’t affected by electrical noise of any kind you don’t have to worry about false indications from the sensor and you don’t have to worry about electrical noise or EMI finding its way back to your control panel because there aren’t any copper wires for it to travel on. Any of those situations are ideal for Fiber Optic Sensors. AutomationDirect offers a range of Fiber Optic Sensors from simple basic sensors where you just buy the configuration you want and plug it in through fully configurable sensors where you can have up to 15 fiber optic sensors connected to one electronics unit. For the basic sensors you just select whether you want NPN or PNP outputs, pig tail or connectorized wiring and if you want to teach the detection range or use a potentiometer to set it. Then you select which optic cable you want to use. Do you want to use a separate transmitter and receiver optic so you can set it up as a through beam detector or do you want a single head that does both so you can set it up as a diffuse photo sensor. For the diffuse optics you can see they have two fibers going to the sensor head – one sends the light out, the other receives the light and sends it back to the sensor electronics. These fibers are literally just light pipes. If I hold the sensor head up to a green LED you can see the other end of the cable light up. If I hold one of the other ends up to a GREEN LED you can see that side of the sensor head light up and if I hold the other cable up to the LED you see the other side of the sensor head light up. There’s a standard head like this, and one like this where you can insert it into areas where you might otherwise not be able to reach. The through beam cables for these basic sensors are available in several different ranges. The only difference is the fibers have different thicknesses. The larger the diameter of the fiber, the more light it can transmit and receive, the greater the detection range will be. If I light up two different cables with an LED you can actually see the difference in the diameter of the cables. Ok, so that was the basic fiber optic sensor – you just select the sensor with the features you want, select the sensor head you need, cut the fiber cable to the length you need with the provided cutting tool, insert the fibers in to the unit – there’s little arrows on the sensor to tell you which hole is transmit and which is receive - and clamp them down and you’re done. Easy. There’s a separate video that shows you how to setup this kind of sensor using the front panel buttons or the potentiometer if you prefer to use that. If you need more flexibility than that or you think your needs might change over time, or you aren’t sure exactly how the sensor will be ultimately deployed, then take a look at the OPT Series Fiber Optic sensors from Wenglor. With these, instead of buying a different dedicated sensor for every application, you just buy one and configure it to do what ever you want. And since you configure it, you have a LOT more options and features you can customize to your application. That gives you a lot more flexibility, allows you to experiment with different configurations to get the best possible performance and it doesn’t tie your hands like the single purpose basic sensors do. And the best part is … the basic version of these configurable OPT Fiber Optic sensors actually costs less than any of the DF series sensors. Here’s a side by side comparison showing the difference. They all have an output to indicate the presence or absence of an object, but this one can handle up to 15 fiber optic cables at the same time. The base unit can handle 3 fiber optic cables, and then you can add up to 12 more fiber optic cables by attaching add-on modules. And yes, you can swap them in and out while the base is running. We’ll cover this in more detail in the quick start video for this sensor, but I do need to point out that only 13 of the 15 possible inputs have physical outputs via these M12 Disconnects. The last two inputs can only be accessed via software using the IO-Link feature we’ll discuss below. They all have some kind of indicator so you can see when the object is detected They all do both through beam and diffuse type of detection – which really just depends on which type of cable you plug in – the cable with separate transmitter and receiver heads or the cable with a single head that does both. Here are the detection ranges you can expect with these guys. Remember that with the basic sensor the range is changed by changing the diameter of the fiber in the cable. With the OPT Fiber Optic Sensors you can do that too but you can also adjust the sensitivity with a parameter. The OPT Sensor fiber optic outputs can be configured for Normally Open or Normally Closed, NPN or PNP, Push-Pull, and can even be configured as a pulse out instead of a level. The 2040 has NPN and PNP outputs, the 2041 has PNP and Push-Pull outputs, and the 2043 does all three. These two have OLED displays which make setting up and testing the sensor so easy – I love that I can actually see the signal strength graphically on these sensors. The basic models only have a basic teach mode and two of them let you adjust the detection distance with a manual potentiometer. With the OPT Fiber Optic sensors you can do a normal teach – which sets the detection threshold at the center of the object. The Minimal teach mode sets the detection threshold at about 17% past the object distance. Maybe you have other objects coming down the line that you don’t want to detect and they are larger than the midpoint of the box for example. The two-point teach gives you a little more control over that detection level. You detect both objects and the sensor automatically sets the threshold between them. Dynamic teach is very similar to that, except you put the sensor into a record mode, run the objects by it, and it automatically determines the min and max distances and sets the detection threshold between the two. So it is just a dynamic version of the two point teach. With background teach, you just teach the sensor where the background is and it automatically sets the detection threshold just above the background, so now it will detect pretty much ANY object that passes by. Window mode setups up a window around the object so the sensor won’t detect objects above or below a certain range. And with these OPT Fiber Optic Sensors you can adjust the window width and the hysteresis around that. And on some of these you can even do an external teach where an external trigger triggers the teach function. The OPT Fiber Optic sensors have a LOT more cable options – we’ll do a separate video on all of those and how to choose the right one for your application because it’s kind of hard to wrap your head around all of the different options. The OPT Fiber Optic sensors let you adjust the on/off delay and the measurement speed and some have adjustable filtering to help smooth out the signal in noisy environments. And these two sensors support I/O link so if you happen to have an I/O Link master, then it can read and configure the sensor automatically for you. At the time of this video AutomationDirect doesn’t sell or support I/O Link Masters so please don’t call asking about that – they won’t be able to help you. Check out these quick start videos to learn how to setup and configure the OPT Fiber Optic Sensors. If you need any help, please contact AutomationDirect’s free award winning tech support during regular business hours. They will be happy to help. And don’t forget the forums! There are lots of folks there that love to share their years of experience. Just don’t post any questions for AutomationDirect’s support staff there – they don’t monitor the forums on a regular basis.