One of the more interesting products I saw at the Hannover Messe in Germany last week were these new rotary encoders from the people at SIKO. Safety guidelines for mobile machines have been top of mind, even before the introduction of EN ISO 13849. With the release of EN ISO 13849, many things have changed with regards to reliably recording angles and displacements. But new draft standards like EN 13000 for mobile cranes or EN 1175 for forklifts even go a step further, requiring additional measures. It’s not always possible to find a sensor on the market that fulfills the standard while also meeting requirements for robustness and long service life. What’s more, these sensors might not be available with the necessary flexibility in terms of interfaces or connection technology.
SIKO GmbH from Buchenbach, the German specialist producer of sensors for linear and rotary path and angle measurement, has developed a suitable product for the mobile machines market to solve this problem. With the new redundant absolute rotary encoder VW58MR, SIKO offers a rotary encoder that allows its customers to keep a firm grasp on angles and paths, even under the most extreme conditions. The rotary encoder has a category 2 construction, allowing it to be used up to SIL2 and Pld.
A jack of all trades
The rotary encoder is based on robust magnetic scanning technology. The measurement range of 4096 revolutions (12-bit Multiturn) is broken into 16,384 steps (14-bit). SIKO uses a newly-developed and reliable gear to allow the Multiturn to capture information. In contrast to battery-powered or self-contained Multiturn technologies, it continues to reliably deliver position values for years to come. The two galvanically separated sensor units of the rotary encoder record positions entirely autonomously. Absolute position and speed are continuously provided to the controls through the interface. Customers can choose from three different versions of interface. In addition to a version with two separate CANopen interfaces, customers can also choose from a version with bus-in bus-out and two node IDs, and one which reliably transmits via CANopen Safety. This provides customers full flexibility, allowing them to adjust the encoder to their applications. Whether clients are interested in two separate CAN bus lines or in transmitting reliably through CANopen Safety, the WV58MR offers multiple options.
A hardcore encoder
The encoder is tough enough to handle even the most extreme environmental conditions. Extremely robust and resistant to environmental influences, it withstands the harshest weather conditions. With protection class IP65/IP67, a wide temperature range of -40° C to + 85° C (-40° F to 185° F), and a special coating process, it is perfectly suited for mobile machines with tough demands. There is also a version available with a housing that is resistant to salt spray for use in harbor areas. Its especially strong double ball bearings mean high axial and radial loads on the shaft are no problem for this compact “hardcore encoder.”
The specialist for slewing ring positions
But the encoder doesn’t just gain bonus points for its technical specs. It also has internal functions that make integration significantly easier for machine designers. We have developed specialized software specifically to record slewing ring positions. Because the encoder is usually connected to the slewing ring via an external gear, which can also result in uneven gear ratios, conversion to a 0° – 360° value is not always easy for the machine manufacturer. This is because the position of the slewing ring should always be able to be resolved into 360°, no matter how often the slewing ring turns in one direction and even if the rotary encoder exceeds its internal zero point after 4096 revolutions. SIKO has implemented special software in the new WV58MR rotary encoder for this purpose. This software allows you to configure the number of teeth for the slewing ring and the number of teeth for the external gear in the rotary encoder. This allows manufacturers to generate any gear ratio. This means the rotary encoder returns the exact position and speed of the slewing ring via the interface, relieving the machine manufacturer from having to recalculate the position. This software makes the rotary encoder easy to integrate into any machine. Manufacturers can always use the same encoder system, no matter how big the slewing ring is. This allows the machine manufacturer to limit the number of versions, saving money and increasing the number of units available for sale. This is a true win-win situation in both development and production.
The benefits are obvious. With the WV58MR, SIKO offers its customers a flexible rotary encoder solution that solves multiple problems at once. The encoder fulfills norm requirements, lessens environmental impact, and—thanks to its intelligent features—makes integration as efficient and simple as possible. A true advantage for machine manufacturers and users.