Almost 10 years ago, TWK launched the functionally safe encoder with PROFIsafe via PROFINET interface. The TRT/S3 model was one of the first certified models of this type available at that time. Of course, extensions and improvements were made over time. Now, a new generation is coming onto the market that features a significant innovation boost.
First of all: The new version is compatible with the previous version, so that an exchange or an extension in existing plants and systems can be carried out easily and without changes and without having to exchange the GSD file. Furthermore, a free module selection is possible. This means the TRT/S3 automatically adapts to the module selected in the project planning. Reprogramming of the encoder is no longer necessary. Due to a 14 mm shorter housing length, it is even more compact than the previous version. The encoder, which is available as a multiturn or single-turn device, is SIL2 and PLd certified according to the IEC 61508, IEC 62061 and ISO 13849 standards, with improved safety characteristics. New is an increased electromagnetic compatibility according to standard IEC 61326-3-2 and a UL® approval according to UL61010-1, so that nothing stands in the way of worldwide use.
The maximum resolution of the magnetic scanning system has been increased from 13 to 16 bits (65536 steps/revolution) with an accuracy of better than ±0.2 %. For the singleturn even better than 0.05 %. In addition to the output of a precise position signal, these values make it possible to derive an exact, functionally safe speed signal in order to use the encoder for speed monitoring, for example in automated guided vehicles (AGVs) or in rotors of wind turbines. In the version with protection class IP65 (without shaft sealing ring), a shaft speed of up to 5000 rpm is now possible.
The PROFINET/PROFIsafe profiles have been updated to V2.42 and V2.6 respectively, whereby the older PROFIsafe profile V2.4 is still supported, as is the encoder profile 4.2 known from the drive sector, which will be available from firmware version 4.1. The cycle time is a minimum of 250 µs.
As usual from TWK, the new TRT/S3 is available with a variety of selectable mechanical and electrical features: different housing, flange and shaft shapes – from the smallest unit with 42 mm diameter to special designs with 160 mm adapter flange or units for explosion protection zones 1/21 and 2/22 according to ATEX/IECEx, each in aluminium or stainless steel. Depending on the version, axial or radial plug or cable connections can be realised. Diagnostic LEDs facilitate implementation and function control.
Special software for slewing ring applications, which calibrates the position signal directly to the slewing ring, ensures that the position signal has a zero transition when the slewing ring makes a full rotation, so that one always knows in which direction the jib of a mobile crane, for example, is pointing. The position signal goes from 0 to 360° with parameterisable transmission ratio and resolution. This output code continues to work reliably even if the encoder’s measuring range of 4096 revolutions has been passed through and continues to be rotated. When using the special ZRS target wheel from TWK, minimal slewing ring movements can be detected. In this way, the safe encoder is joined by a mechanically backlash-free connection for a precise and safe system.