by Jarrod Orszulak, Product Manager, POSITAL-FRABA
The latest programmable encoders offer both incremental and absolute functionality on one hardware platform and can be programmed with a WiFi connection.
Programmable incremental encoders have become more common recently. This is largely due to the fact that the measurement characteristics of the device (number of pulses per rotation, output level and so on) can be modified through a software update without requiring any changes to physical components. Now, however, engineers at POSITAL have taken the programmability concept to a new level with the new generation of iXarC rotary encoders. These new encoders offer both incremental and absolute encoder functions on a single hardware platform; are available in a range of mechanical configurations and connector types; are supported by a range of configuration management tools that can be accessed by end users over the full working life of the encoder; and can be programmed by any WiFi-enabled electronic device.
Of course, programmable encoders are not new. For instance, a traditional programmable encoder can allow users to program basic encoder parameters such as the resolution or the electronic interface level. Then there’s the method of programming itself. The simplest method may be with mechanical DIP switches. Others methods include using a simple serial interface such as USB or part of an integrated system connected with a PLC or HMI. What is new with these latest encoders is the kind of programmability as well as the way they are programmed.
Benefits of programmable encoders
Encoders are used to monitor position and motion within machines in many different industries. They are an essential interface between the mechanical components and the control system of a machine, so that functional requirements are as diverse as the range of applications. This diversity has led to a huge variety of available incremental and absolute encoders.
With programmable encoders, much of the variety in measurement characteristics can be accommodated through software changes so that the range of hardware devices needed is significantly reduced. Distributors or system integrators can stock a limited number of hardware versions and still meet customer requirements quickly and efficiently. This means that users and distributors can reduce their stock levels and spare-parts inventories significantly. Prior to delivery or installation, the encoder’s measurement characteristics can be set up quickly. Moreover, the same device can be easily updated at some future time if the machine is changed or upgraded.
Once the encoder has been configured, it’s extremely useful to keep records of the configuration. This is especially important for the end user because a spare part might be required many years later. At this point in time, handwritten notes on the label might be difficult to read and the system integrator who did the original setup might no longer be available. Many programming tools on the market are unable to save and manage records of configuration data.
Incremental or absolute? Or both?
Traditionally, incremental and absolute encoders have been built around different design concepts. Moreover, features like resolution or multi-turn capability have been defined by different components such as code discs. The iXarC encoders are designed using a different approach.
All electronic components of a multi-turn encoder are integrated on a single 35-mm printed circuit board. No backup battery is required as this technology is capable of generating a sufficient amount of energy to record complete revolutions when the shaft of the encoder is turned. This energy generation does not depend on rotational speed. As a result, the encoder can be rotated for an indefinite number of times over long periods—with or without external power being available—without losing track of its absolute position. A powerful microcontroller and signal-processing platform within the encoder is used to create incremental output signals and calculate absolute position data that are transmitted on an SSi interface for absolute measurements and TTL or HTL interfaces for incremental readings. By changing the software configuration, this encoder platform can become a pure incremental encoder, a single-turn encoder, a multi-turn encoder or an encoder with SSi+ incremental output.
POSITAL’s programmable encoders are available in a large variety of mechanical configurations, including 36, 42 and 58 mm flanges and a variety of shaft types (solid shaft or blind hollow shaft versions with a range of shaft diameters). Additional adapters and flanges ensure compatibility with all common standards in America, Asia and Europe. Radially or axially positioned connectors and cable outputs are both available. Heavy-duty versions with an IP protection class of up to IP69K and up to 300 g shock resistance are available in both aluminum and 316L grade stainless-steel housings.
Because a small number of devices can be programmed to take on a wide range of measurement tasks, distributors of incremental encoders can reduce their inventory levels by up to 80%. OEM customers using a variety of different incremental and SSi encoders can now cover different applications with a small number of devices, greatly simplifying supply chain and inventory management. System integrators can decide at the last minute how to tailor the encoder to specific requirements on site and initiate the purchase of the encoders while final design requirements are still under discussion. End users can receive spare parts from a distributor or system integrator quickly, reducing both downtime costs and shipping costs.