TWK's new NOCIO/S3 with IO-Link interface is a sensor that is triple certified in terms of safety: according to IEC 61508 & ISO 13849 & UL 61010-1. This sensor - a backlash-free electronic cam controller - contains not only concentrated encoder know-how, but also a high degree of safety functionality - coupled with innovative new features in its two interfaces: IO-Link and safety switching outputs.
Specifically: The electronic cam controller and its two safety switching outputs are SIL2 and PLd certified and there is a UL® approval according to TYPE 1. The functionally safe NOCIO/S3 is therefore also used where the corresponding UL® safety requirements are demanded.
The IO-Link interface is new in the field of TWK cam switches and will be implemented in another sensor, the IWIO inductive displacement transducer, shortly after its success with the NOCIO. One advantage of IO-Link is the simple connection to the control system. Decentralised IO-Link masters are integrated into the main bus system - e.g. PROFINET. Several peripheral sensors can be connected to each master with simple 3-wire cables and can thus communicate with the central control. With the help of the IODD file, the input and output data can be displayed and formatted in a user-friendly way, including the safety CRC checksums and valid flags.
The two independent safety switching outputs are equipped with safety relays. The respective positively driven second contact informs the microcontroller whether the correct switching state is present according to the parameterisation and the current measured value. If not, the NOCIO assumes the safe state, opens all contacts and sends an alarm message to the controller. In addition, a second relay per switching contact is connected in series with the safety relay to ensure safe contact opening. For example, for the interruption of a safety chain. The switching contacts can react bit-exactly to limit values of position, speed or acceleration of the encoder shaft. An adjustable hysteresis avoids contact chatter.
An important area of application for the robust and compact cam switchgear is wind turbines. Here, the angle of rotation of the nacelle is measured as part of the azimuth adjustment and transmitted as a position datum. As soon as critical limit values are reached - in both directions the nacelle must not be turned too far due to the wind tracking - the safety switches open to stop the turbine and return it to the centre position. With the backlash-free ZRS measuring gear, the unit can be connected to the spider.
A measuring range of 4096 revolutions at a resolution of 16 bits per revolution, various housing materials for onshore and offshore use with protection class IP67 and signal LEDs for the operating status round off the versatility of the NOCIO/S3.
