Design
Figure 1 : The explosive growth in the installed base of IO-Link Sensors
One reason that this standard is enjoying rapid adoption in factories in Europe first and increasingly around the world is that connected , smart sensors underpin the industrial IoT that is beginning to be deployed in factories .
Defining Industrial IoT
Industrial IoT is the Internet of Things within an assembly line , factory , oil field , even in a jet engine or any such industrial environment to help us better run that particular process .
While one day we may all want connected toasters and refrigerators ( for a yet to be determined reason ); it is clear that connected factory / process automation systems can quickly deliver significant benefits . Understanding and measuring the heat profile of actuator or the vibration over time of a motor allows us to wring out significant operational efficiencies from the assembly line . Over time , a connected , digital factory can also exploit new business models and adapt production to market needs in real time .
Industrial IoT is an attempt to connect up all the pertinent data from a process or from an assembly line to be able to make intelligent decisions – such as predicative maintenance , running at optimum efficiency , better production scheduling , improving production mix , etc . As we start connecting up data from the myriad of different sensors across the production line , everimproving software and algorithms promise to give us more insight and understanding of our production flows .
Figure 2 : Understanding industrial IoT in terms of a stack
One way to visualize Industrial IoT is in terms of a stacked pyramid , as shown below . At the very bottom are sensor data – which must be detailed , actionable , as well as useful for analysis . The glue for industrial IoT is data , or more specifically smart sensor data . This means more than just ON / OFF signals . Let ’ s illustrate that with a few examples . It is not enough to detect proximity – we need to know how close the product gets to the motor . It is not enough to detect a light curtain breach , as we need to know which quadrant the breach seems to be happening in . In short , we need the sensor to transmit complex data and not just an ON / OFF signal . This is where the new IO-Link protocol for transmitting sensor date comes in .
What is IO-Link This is how the IO-Link Association defines this standard
“ IO-Link is the first standardized IO technology worldwide ( IEC 61131-9 ) for the communication with sensors and also actuators . The powerful point-to-point communication is based on the long established 3-wire sensor and actuator connection without additional requirements regarding the cable material . So , IO-Link is no fieldbus but the further development of the existing , triedand-tested connection technology for sensors and actuators .” 1
The key thing to note here is that this is an open standard and is based on the legacy 3-wire sensor connector that everyone is used to . Over this cable the protocol supports communications at data rates up to 230kbit / s .
The connection between an IO-Link Master and slave is via a maximum 20ft long 3-pin cable .
Figure 3 : An IO-Link cable based on a ( mostly ) legacy m12 connector
The IO-Link master establishes the connection between the IO- Link devices and the automation system . As a component of an I / O system , the IO-Link master is installed either in the control cabinet or as remote I / O which communicate via regular fieldbus networks to the controller .
Example IO-link Sensors : Tiny , Smart & Connected
Today ' s factories rely more on automation and less on manual labor . With this increased use of automation & robotics comes the increased need for proximity sensing . Proximity sensors are devices that can sense when an object is a specific distance away from a reference point location . They are able to act as a switch by flipping when the target object passes a predefined distance threshold . They can also provide continuous readings when objects are changing distances within a sensor ' s range . Several types of proximity sensors exist today such as optical , inductive , capacitive , ultrasonic , magnetic , and even mechanical .
Shown here is a tiny IO-Link proximity sensor with an IR receiver , matching IR LED driver , IO-Link transceiver , and energy-efficient step-down converter all on an 8.2mm x 31.5mm printed circuit ( PC ) board . The Maxim reference design in Figure 4 consists of an industry standard Maxim Integrated IO-Link device transceiver
ELE Times | 31 | March , 2017