If the safety standard cannot be used, special solutions can be found in the safety sector.
The subject of safety is subject to strict standards. That's good. Not everyone should determine at their own discretion what is and what is not sufficient to prevent personal injury and damage to property. Nevertheless, safety concepts are always individual. It is possible to make adjustments within the standard criteria, whereby the overall concept still meets the safety criteria.
TWK has been active in the field of safety sensors for many years and is market leader in many cases. And we respond to the requirements of our customers who cannot use anything 'off the peg'. For example, we have developed a safety encoder with CANopen interface, which has a special transmission protocol (SIL2/PLd). In this case, the customer could not use the usual SRDO (Safety Relevant Data Object) with the associated transmission conditions, but a modified standard protocol (PDO: Process Data Object). In addition to the required position data, this PDO also contains an 8-bit sequence number which is decremented by 1 for each newly determined, i.e. 'real' position value. In addition, a 24-bit CRC is generated via these two data and also transmitted in the same PDO. The reading control now expects the PDO of the encoder in a fixed time pattern, and the two measures ensure that the position data is current and additionally protected by a CRC. This variation of a safety encoder makes it possible to provide a certifiable solution for this task.