kubler articles

Safe Connections: Safe motion and bellows couplings for encoders

Kubler 11/1/2014

Safe ConnectionsKubler has announced a product offering for the second half of this year. Alongside the encoders offered there are also, in focus, the bellows couplings, as a security module for the speed and position acquisition, between the motor and the encoder. The Safety-M module was developed in co-operation with Bihl+Wiedemann

The new generation of safety modules is comprised of a base module and an expansion module, both have SIL3/PLe and UL certification. The expansion module for axis extension capability provides a connection from the encoders, thereby allowing a simple import of the encoder data. The Safety-M modular base module combines the capability of precision control, i.e. the application of speed and position detection, with master functionality.

Two variations will be offered. A standard module with digital I/O and also a version that functions as a gateway with standard and secure Fieldbus capability. Both offer a removable smart card, on which the configuration data is stored. This is an advantage when exchanging devices. The devices are totally programmable and can operate with related safety critical functions, emergency stop switches, two handed control, light barriers, and operating mode selectors.

It also functions with other secure control units. The modules, when connected together, will provide an absolutely secure communication link between each other. The Safety-M expansion module serves as a secure position and a motion monitor. Also, these axis expansion modules have secure digital I/O available. All modules offer a removable smart card for storing local data (encoder type, resolution, etc.).

The axis expansion module can be connected to incremental or absolute encoders. Each module can monitor up to two axes. The devices have complete speed and position security functions, pursuant to EN 61800-5-2, integrated into the firmware. The safe speed and/or position acquisition as well as one or two encoder monitoring capability is supported. Through the front panel Teach-in Rotation Count is available. The expansion modules have connections for secure sensor systems such as (for example) light barriers, laser scanners, emergency stop switches, etc.

Safe bellows couplings

A new product addition is the specialized bellows couplings for the Sendix SIL shaft encoder; a safe connection between the motor and the encoder. In the case of loosening or damage to the spring elements a catch mechanism consisting of two internal clips on the shaft of the encoder ensure that a continuous connection is maintained. Like the standard couplings they allow for a self correction of the angular misalignment, both axial and radial, between the motor and the encoder.

The stainless steel couplings are shock and vibration resistant and have a operating temperature range of -22ºF ... 248ºF [-30ºC ... +120ºC]. Angular misalignment can be corrected up to maximum shaft misalignment of ±0.0118” [±0,3 mm] radial, ±0.0177” [±0.45 mm] axial, and 3º angular. Various shaft bore diameters are available in 0.393 x 0.393”, 0.393 x 0.472”, or 0.472 x 0.472” [10/10, 10/12, or 12/12 mm].

Comprehensive encoder advances

To introduce the multitude of new encoders here is a short presentation of a few of our products. Low-cost incremental encoders: Whereas the trend in the high end market is going toward absolute, Fieldbus, and Ethernet, there is always an interest for incremental encoders in the costsensitive, light machinery arena. The optical encoder KI40 has a housing size of 40 mm and is predominately for the Asian and American markets but also to serve the low cost segment.

The device is available in solid shaft or hollow shaft versions. Hollow shaft versions are 8 mm deep. The degree of protection provided by IP64 is a temperature operating range of -4ºF ... +158ºF [-20ºC ... +70ºC] and 100% magnetic field resistance. The resolution averages out to 2,500 pulses per revolution. Other configurations (connectors, cable lengths, etc...) are possible through request. Energy Harvesting for the magnetic multiturn encoder: The magnetic multiturn encoder, Sendix M36, has a housing size of 36 mm.

The device is in a IP67 pressure cast housing and has a temperature operating range of -40ºF ... +185ºF [-40ºC ... +85ºC]. The 36 mm version has a blind hollow shaft to 10 mm also available. The new variants with magnetic Energy Harvesting Technology are extremely compact and provide cost effective solutions. Absolute encoder with Modbus RTU (remote terminal unit): The Sendix F5868 and F5888 encoders, members of the F series multi-turn family, with high resolution Modbus. They are encoders with hollow through shafts up to 15 mm and an over-all body size of 58 mm. The optical encoder, without the gear mechanism, is based on Intelligent-Scan-Technology.

Through the complete integration of both the single-turn and multi-turn functionality with an integrated OptoASIC, the encoder is 100% magnetic resistant. ATEX/IECEx shaft encoder for mining operations: The incremental Sendix ATEX/IECEx 71xx encoder is certified for M2 mining operations. The adoption of the IP67 pressure cast stainless steel housing, with safetylock-design, is IECEx certified in zones 1, 2, 21, and 22, throughout Europe, and thanks to IECEx possibly world wide. They operate at a resolution up to 5,000 pulses per revolution and have a temperature operating range from -40ºF ... +140ºF [-40ºC ... +60ºC].