Tech Tip: OPT2040 Fiber Optic Sensor Quick Start

OPT2040 This sensor works with both Plastic and Glass fiber cables. It’s important to understand that the color and reflectivity of the object the sensor is looking at determines the detection range capability of the sensor. The brighter the object, the easier it will be to detect. For example this white object is detected here, but this dark object has a much shorter detection distance for the same detection distance setting. There are 4 connections via this M8 connector – The supply line, signal out and contamination out. You can mount it via 35mm DIN rail or Side mount via these screw holes. Beware that there is a max ambient light spec. If there is too much light in the room the sensor will have difficulty. The spec for this sensor is 10000 lumens max. And full sunlight can be well over that per square foot, so you probably won’t want to use these in daylight applications. Suppose we have an object that triggers a through beam sensor and one that triggers a reflective sensor. The light received by the sensor would look like this for through beam where the light gets blocked when the object passes through the beam and like this when the object reflects light back to the sensor. And when you have the sensor setup as a normally closed ouput, the signal goes in-active when light is received. So for a through beam sensors the output signal is inactive while it sees the light and goes active when the beam is broken. The reflex sensor only sees light when the object passes in front of it so the normally closed signal drops during that time. For normally open outputs – the signal goes active when the sensor sees light, so the results are inverted. On delay delays the output relative to the light turning ON, so it delays this for Through beam and this for Reflex. Off delay, delays the output relative to the light turning off, so it delays these. Both delays can be set from 0 to 200ms in 10ms increments. You just rotate this switch to the delay setting and press the plus or minus buttons. With the switch in this position, the yellow LED blinks to tell you what the current setting is. This is blinking 5 times between pauses – each blink is 10ms - so we know this delay is 50ms. Let’s change that to 100. We just press the plus button 5 more times to get another 50ms … and verify that the LED blinks 10 times. Perfect. The delay is now set for 100ms. Don’t forget to switch the rotary switch back to RUN. If the plus LED is lit, then the output is in Normally Closed mode which switches on absence of light or dark switching and normally open – which switches on presence of light is the minus button. To switch it, just press that button and rotate the selector switch back to RUN. To select the output type, go back to the Normally Open/Normally Close PNP NPN switch selection. This time hold the plus button down for 5 seconds. You will see both buttons blink. Press plus for PNP – think of P for Plus and PNP – minus for NPN – think of N for Negative for NPN and press both for Push Pull. Rotate the selector back to RUN. To manually set the switching distance, rotate the selector to this Potentiometer setting. Press the Plus button to increase the detection distance. It’s LED will blink when you hit the max. Press minus to decrease the detection distance. It’s LED will blink when you are at the min. This sensor is set for dark on so the LED is active when there is no object. So this means we are NOT detecting the object so let’s increase the detection range until the LED goes off by holding down the plus button. I probably went a little past it so lets hit the minus until the LED comes back on, then I’ll press the plus button one more time to get right to the detection threshold. Now the object is detected at the correct range. Perfect. And of course, switch the selector back to RUN. This sensor support s four automatic teach modes. For Normal Teach you just switch to Teach mode, put the object in front of the sensor or no object if you are doing through beam, press the plus button – Plus LED will light up – Then press the plus button again. The LED turns off. Rotate the switch back to RUN. The object detection range is automatically setup for you. Sure enough the sensor detects this object at the taught distance. I should point out that you have about 40 seconds between button presses before the sensor times out. Minimal Teach is the exact same thing, but use the minus button for both button presses. For Dynamic Teach – which learns as the objects goes by - rotate to Teach. Press and HOLD the plus button until it blinks – that will take about 5 seconds. The sensor is now recording so have the objects move by. When done, press the plus button again and switch back to run. And sure enough, the sensor doesn’t see the far object, but does see the close one. Perfect. The Two Point teach is very similar to dynamic, except you manually tell it which two objects to set the threshold between. Rotate to Teach. Point sensor at object A, press the plus button – it lights up. Put object B in front of the sensor - or no object if you want to detect the conveyor or wall – and press the minus button. – it lights up. Rotate back to RUN. Sure enough the senor detects the large object but not the small one. Perfect. External Teach does the same thing, but you apply a voltage to one of the pins instead of pushing the buttons to trigger the settings so we’re not going to cover that here. When in Run mode, the yellow LED indicates detection, the RED LED indicates contamination and the plus and minus buttons don’t do anything. You can change the LED switching frequency between these numbers. That’s helpful if you have two sensors in close proximity. If you set them up with different switching frequencies, they will be less likely to interfere with each other. Switch to power save, No LEDs tells you it is switching at 10 KHz, Plus LED is 7.58kHz, Minus LED is 6.1Khz. Switch back to RUN. If you leave the switch in power save mode the output frequency will be reduced 5.06 Khz and the power consumption is reduced by 40%. That’s done by mostly by cutting the switching frequency of the sensor in half from 2 KHz down to 1 Khz. The switching frequency determines how fast the sensor will react to an object passing by. That ought to be enough to get you started. If you have any questions, please don’t hesitate to contact AutomationDirect’s free award winning tech support during regular business hours. 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 team there – they don’t monitor the forums on a regular basis.