Sensors take on more and more functions. To do so, they must be parameterised. Here the IO link comes into play: as a manufacturer-independent standard for sensors and actuators. The IO link was designed to cover the last metre between the I/O module and periphery thus enabling the digital process data transmission without conversion losses and the transmission of the complete parameter set of the periphery. Safe connection is ensured using the ecolink M12 connector.
The IO link is a point-to-point interface for the connection of any sensors and actuators to a control system. In contrast to conventional fieldbus systems, there is no bus wiring but parallel wiring. Binary or analogue sensors and actuators can be equipped with an IO link interface. Visually, IO link sensors look exactly like standard sensors. The only difference is a combined switching status and data channel. This channel is connected to the same pin as the switching output of conventional sensors.
The developers tried to design the IO link technology in a manner as compatible as possible with the existing periphery. So every sensor working in the SIO mode can be operated at any binary inputs of controllers or bus modules. Conversely, conventional binary electronic or mechanical sensors can be operated at IO link ports. In both cases the switching signal can be collected cyclically. The parameters of intelligent IO link sensors are set using the pushbuttons at the sensor, a hand-held parameter setting unit or the PC. When using a continuous communication from the control level to the process level the parameters can be transferred via the IO link modules and the corresponding fieldbuses. So the plant controller can also carry out parameter setting. It is also ensured that units with new technology function in combination with existing systems, which allows successive retrofitting and investment the plant operator can split up over time.
As for the AS-interface, no special knowledge or tools are required for the replacement of IO link units. The sensors are replaced in the same ways as conventional units, just plug & play with the additional advantage of automatic parameter setting in the background. This results in shorter downtime or – seen the other way round – higher machine uptime for the plant operator.
IO link in the automation pyramid
IO link and AS-interface are meant for each other. AS-interface established itself on the market as a very simple bus system for the transmission of analogue and binary signals. It is the simple on-site wiring technology with decentralised Ethernet gateways and the quick flat cable connection technology with protection rating IP 69K.
When looking at the automation pyramid it can be seen that IO link units are directly coupled to the process. They take the physical signals, convert them and transfer them to the next higher level. This can be any known field bus. But to ensure this wiring is as short and efficient as possible, which shortens the error search considerably, the AS-i interface could be chosen because it is the only fieldbus which offers field modules in steps of four ports.
At the SPS/IPC/Drives 2006 ifm electronic presented the first IO link units. The connector for the sensor is also part of the last metre between sensor and field box. With ecolink ifm offers a solution providing vibration protection.
Reliable sensor connection
With ecolink M12 the outer ring of the stainless steel sleeve serves as a seat for the sensor connector. This ensures that the sealing ring is protected against excessive pressing from the coupling nut and permanently ensures optimum efficiency. Moreover, the sleeve serves as vibration protection. The saw-tooth type locking operates asymmetrically. It ensures easy mounting of the connector and, at the same time, a higher locking effect when it is removed. This achieves almost complete protection against shock and vibration. This is proven by test series of 1 million impacts at 750 g. The connector is mounted and removed without tools.
A further improvement for the user has been made in the versions with LED. Most LED connectors consist of a transparent plastic housing through which the LED light is visible. Disadvantage: in cases of bright sunlight or lighting conditions the LED light is no longer contrasting with the clear transparent background. Here ifm electronic breaks new ground using black transparent plastic. Light transmission is very high so that the light is barely dimmed. The advantage: high contrast between the LED colour and the black housing of the connector.
The M12 ecolink is suitable for operating temperatures of -25 to +90 °C. The product holds the cURus approvals and is therefore accepted worldwide. A version for the food industry is in preparation.
IO link cpp 448
M12 ecolink cpp 449
With a new design
ifm electronic’s corporate design underwent a considerable change after 17 years and has been presented in its new design as from October 2006. From 1 October 2006 to 31 March 2007 ifm’s modified company logo is being introduced worldwide. Since its foundation 37 years ago ifm’s logo has undergone seven changes. In the first 20 years changes were made six times – in the last 17 years there has been no change at all. This had the advantage of a high degree of continuity in ifm electronic’s corporate design and a memorable company logo worldwide for customers and suppliers.
On the other hand, the disadvantage of a 17 year old logo is that it no longer complies with today’s requirements in all areas. Readability and the strikingness of the logo on large surfaces, in particular, were difficult to implement with the old logo. In 2003 the management therefore decided a redesign of the company logo was necessary.
The new logo is now available. The first public presentation took place at the SPS/IPC/Drives in Nuremberg. At this exhibition the company presented itself with a fair stand in a completely new design.
More about IO-Link
M12 ecolink
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