posital - Motion Control Tips

Closed-loop motor feedback with the absolute advantage

July 12, 2018 By Paul Heney Leave a Comment

Posital has expanded its line of kit-style encoders for feedback for servo and stepper motors with new models that use the same mounting form factor as incremental kit encoders from US Digital, Broadcom and other manufacturers. This makes it very easy to upgrade a motion control application from incremental to absolute position control.

With Posital kit encoders, the control system always has complete information on the physical position of the mechanical components that it is directing. “Absolute position feedback is a natural way of providing accurate position control,” said Jim Stevens, market specialist for robotics at Posital. “Almost any position control application could be absolute-based. Many current systems were designed around incremental encoders because incremental feedback devices were historically less expensive than their absolute counterparts.” However, with Posital absolute kit encoders available at prices much more in line with incremental devices, system designers no longer have to work around the shortcomings of incremental feedback in an absolute position world.

“Incremental encoders are effective for speed control. However, to monitor absolute position, the controller needs to maintain a complete count of the number of pulses received from the encoder,” said Stevens.

This can lead to problems. If the pulse count becomes corrupted due to a power outage, or if the control system fails to update the pulse count when the machine moves, positional accuracy is lost. The usual remedy is to “re-home” the machine by returning it to a known reference position and re-starting the pulse counts. By contrast, absolute encoders measure position directly. After a power outage, the controller can re-establish complete knowledge of the position of mechanical components by simply polling the sensors and reading their rotational positions.

“It’s great to be able to simply power up a system and continue a process without having to go through a restart/homing cycle and having to scrap work or material that may be in process,” said Stevens.

Multiturn absolute kit encoders from Posital are based on magnetic sensing technology that provides a very robust encoder solution. The multiturn counting system is powered by Wiegand wire energy harvesting technology, which enables the absolute encoder to maintain true absolute position over power cycles and rotation of the encoder during power-off conditions. With 17 bits (131072 positions) of single turn resolution and 16 bits (65536 turns) of multiturn range, the absolute kit encoders from Posital are suitable for position control applications.

Posital
www.posital.com

POSITAL closed-loop motor feedback for absolute positioning

July 2, 2018 By Lisa Eitel Leave a Comment

POSITAL FRABA encoders for closed-loop motor feedback allow upgrades to existing motion control applications. The mechanical drop-in replacement encoders have the same footprints as US Digital’s E5 models and Broadcom’s (Avago) HEDS-5500 models.

POSITAL kit encoders provide absolute position feedback — to give controls complete information on the physical position of the mechanical components they’re directing.

Many motion designs are designed around incremental encoders because incremental feedback devices were once less expensive than absolute encoders. But now POSITAL’s absolute kit encoders are comparable to those of incremental encoders, so design engineers must no longer make the choice based on cost.

• Identical assembly procedure to that of comparable encoders; no training required; diameters 4 to 10 mm (1/4 to 3/8 in.)

• Magnetic technology (to withstand harsher environments than optical encoders); improved connectivity via m12 connector additional available

Multiturn Absolute Kit Encoders from POSITAL are based on magnetic sensing technology. More specifically, the multiturn counting system is powered by Wiegand wire energy harvesting technology, which enables the absolute encoder to maintain true absolute position over power cycles and rotation of the encoder during power off conditions.

With 17 bits (131072 positions) of single turn resolution and 16 bits (65536 turns) of multiturn range, KCD Absolute kit encoders from POSITAL are ideal for position control applications.

For more information, visit this deep link to the absolute-encoder page at posital.com.

Posital offers heavy-duty encoders for extreme environmental conditions

January 30, 2018 By Miles Budimir Leave a Comment

POSITAL’s heavy-duty IXARC incremental and absolute rotary encoders are built to stand up to extreme environmental conditions. Based on a housing design with a 25-year track record of surviving the toughest conditions, these devices are suitable for marine vessels, off-shore facilities, mines, cranes, wind turbines and other challenging locations.

These sensors feature extra rugged impact-resistant Type 316L stainless steel or aluminum housings with seals rated to IP67. Other heavy-duty features include bearings that can stand up to high mechanical shaft loads (up to 250 N axial, 350 N radial) and the ability to stand up to high shock and vibration impact (200 g and 20 g respectively.) A special shaft-lock mechanism protects the internal components of the encoder from damage due to extreme thrust loads on the shaft. An optional mechanical overspeed switch can provide an additional level of safety for equipment and operators by sending a warning signal to a motor control if the rotational speed of the shaft exceeds a pre-set limit. The operating temperature range for the heavy-duty IXARC encoders is – 40° to 80° C.

The heavy-duty IXARC encoders are available in a wide variety of configurations. Incremental versions have resolutions (pulses per revolution) of up to 2,500 PPR, while absolute versions are available with 16-bit resolution (.005°). Multi-turn variants of the absolute encoders have measurement ranges as high as 16,384 revolutions (14 bit). Other resolutions are also available for both incremental and absolute encoders. Incremental variants are available with Push-Pull (HTL) or RS422 (TTL) communications interfaces, while absolute models can be provided with either CANopen or SSI interfaces. Dual-function models are available that provide both incremental and absolute outputs.

POSITAL IXARC encoders are available with rapid delivery anywhere in the world. Lead times for most configurations are less than 5 working days.

For more information, visit www.posital.com.

POSITAL-FRABA expands North American operations

August 11, 2016 By Lisa Eitel Leave a Comment

POSITAL-FRABA Inc., has announced several management changes. Due to the rapid growth of the company and the need to address the special needs of different markets, a new position of Vice President of Sales has been created. This position will be filled by Wojciech Pajak, previously the head of the company’s global manufacturing plant based in Slubice, Poland (production of motion and position sensor products). Pajak will have responsibility for American markets, with an emphasis on support for system integrators and distributors. Christian Fell, who remains the COO for the company’s North America operations, will also take on the role of Vice President Technology, with special responsibility for product development in custom encoder solutions.

Wojciech Pajak, has been with FRABA since 2006. He is a graduate of the Szczecin University in Poland, with a Master’s degree in law. He also holds an engineering degree in management and production from the West Pomeranian University of Technology. He was elected an equity partner of FRABA in 2015.

Christian Fell joined FRABA in 2000 and became an equity partner in 2007. He has a Master’s degree in physics from the Gerhard Mercator University, Duisburg, Germany and a diploma in medical physics from the Technical University of Kaiserslautern. He headed development of the technology platform for POSITAL’s optical encoder line and helped to create the company’s North American subsidiary, headquartered in Hamilton, New Jersey.

Pajak comments: “POSITAL has been on a very positive growth path and I am eager to help new and existing customers discover the advantages of our products. With my background in production, I am especially enthusiastic about explaining how our unique manufacturing system makes POSITAL a one-stop shop where customers can get the right sensors, quickly and cost efficiently, even for the smallest orders. This is especially important for the incremental encoder market where our products can be configured to meet each user’s exact specs.” Pajak continues: “I am also excited about the new online tools that POSITAL is about to introduce. These will revolutionize the way that customers select and buy encoders”. Fell adds: “We have some highly innovative new products under development that will help POSITAL and FRABA reach new levels of success. I am very pleased to be leading the effort to get these ready for the marketplace.”

Posital
www.posital.com

POSITAL adds Profinet interface to explosion-proof encoder line

July 14, 2016 By Miles Budimir Leave a Comment

POSITAL has added an optional Profinet communications interface to its explosion-proof IXARC rotary encoder family. These devices have been designed to comply with ATEX/IECEx directives for Category 3 electrical products and are suitable for Zone 1 and Zone 21 conditions (potential exposure to hazardous levels of explosive gases and dust concentrations). Areas of application for these encoders include oil and gas facilities, underground mines, chemical plants, milling operations and grain-handling facilities.

POSITAL’s ATEX-certified encoders are built with aluminum or Type 316L stainless steel housings that are designed to contain any electrical hot spots or sparking and to provide environmental protection ratings of up to IP67. Based on POSITAL’s optical measurement technology, these encoders can deliver up to 16-bit resolution in single-turn configurations or 14-bit resolution for multi-turn models. This technology ensures that position measurement integrity is maintained even if movement occurs when system power is unavailable. No backup batteries are needed, reducing maintenance costs. IXARC encoders can be ordered with a wide range of mounting options to ensure that they can be readily adapted to many kinds of equipment.

The new Profinet interface makes these devices compatible with one of the most widely used industrial Ethernet technologies. IXARC Profinet encoders have an integrated IRT switching capability that adds flexibility when it comes to designing the network topology. A built-in bootloader enables in-situ firmware updates, while six diagnostic LEDs simplify setup and troubleshooting. IXARC encoders are available with a removable connection cap, which allows users to choose between axial or radial cable exits.

Finding the right IXARC sensor for a particular application is straightforward. The web site www.posital.com provides a powerful product finder tool that lets users specify product features required for each application and then quickly zero in on the best available products.

For more information, visit www.posital.com.

IXARC rotary encoders with EtherCAT interface

May 1, 2014 By Jennifer Calhoon Leave a Comment

POSITAL’s high-performance IXARC optical rotary encoders are now available with EtherCAT communications interfaces. EtherCAT (Ethernet for Control Automation Technology) is a special
form of industrial Ethernet that eliminates the unpredictable transmission delays that characterize ‘standard’ Ethernet networks. EtherCAT networks ensure very rapid communications between a controller and other devices within a control system so that EtherCAT can be used for systems where real-time control is essential. EtherCAT systems also offer performance and scaling advantages over older fieldbus systems and can make use of inexpensive commercial Ethernet hardware. Both bus and star wiring topologies can be used for maximum flexibility in cable layout.

IXARC absolute optical rotary encoders with EtherCAT offer outstanding measurement performance, including resolution of up to 65,536 steps per turn (16 bits). Multi-turn models with measuring ranges as large as 16,384 revolutions are available. The EtherCAT interface, which was implemented using fast field programmable gate array (FPGA) circuits, provides cycle times of less than 125 microseconds. The distributed clock function allows users to synchronize axes within a microsecond. These encoders support cable redundancy for improved system reliability. Firmware can be updated through standard tools such as TwinCAT, while security needs are addressed with password protection. IXARC optical encoders are available with shaft and connector seals rated at up to IP67 level and with explosion-proof (ATEX certified) stainless steel housings.

Other industrial Ethernet systems supported by POSITAL-FRABA include EtherNet/IP, Profinet IO and MODBUS+ Ethernet TCP.

POSITAL
www.posital.com

POSITAL introduces new high-performance IXARC encoders

November 19, 2013 By Motion Control Tips Editor Leave a Comment

POSITAL-FRABA has revolutionized the world of rotary encoders. The new IXARC encoders combine the accuracy and dynamic response of optical encoders with the ruggedness and compact form factor of magnetic encoders for true ‘go anywhere, do anything’ performance.

Building on the company’s well-proven magnetic encoder technology, these innovative products feature a new four-element Hall-effect magnetic sensor linked to a 32-bit microprocessor running highly-optimized signal processing software. This combination offers levels of accuracy and dynamic that previously required larger, more mechanically complex optical encoders. Their compact size and ability to survive dust, moisture and severe shock and vibration loading means that IXARC encoders can be installed virtually anywhere. The microprocessor-centered design also means that operating parameters such as zero-point, rotational direction and sensitivity can be modified through simple software updates.

The excellent dynamic response of the new measuring components makes it possible to offer both incremental and absolute versions of these rotary encoders. Incremental encoders are typically used in speed monitoring applications, while absolute encoders – including multi-turn models – are ideally suited to position measurement in motion control systems.

Like other POSITAL products, the IXARC line is available with a wide range of packaging and interface options. This includes a variety of instrument interfaces, mounting arrangements, housing materials and shaft seals. Special plosion-proof and safety-rated models are also available. POSITAL’s online “Product Finder” tool helps system designers select a product that meets their exact requirements.

Posital
www.posital.com

Posital’s optical encoders feature a bit parallel interface

February 3, 2012 By Motion Control Tips Editor Leave a Comment

Posital (www.posital.com) has integrated a bit parallel interface to its range of OCD optical encoders, ensuring a reliable, fast transfer of angular position into higher level controllers. These make them suitable for use in remote regions, as they offer easy diagnosis options that come with simple tools.

The OCD optical encoders are based on a single turn sensor that features a highly Opto-ASIC, which offers a resolution of up to 16 bit per revolution. In addition, a maximum of 14 bit (16384 revolutions) can also be measured by a gear in multi-turn variants. Featuring a code disc built from dimensionally stable, break-proof plastics provides outstanding precision, dynamics and resolution.

Posital’s encoders comply with rigid electromagnetic compatibility requirements, as they feature protective circuits for interface connection and power supply. This enables the encoders to provide reliable operation even under harsh conditions. The encoders’ interface design has been extended to include TTL levels for the data outputs. Seamlessly combined with a vast input voltage range, common for the automation industry, the interface design covers almost all possible applications.

The encoders also feature a push/pull technology that allows it to be connected to standard I/O components from different controller manufacturers. Compatible with open collector variants, the robust encoders offer a protection class of up to IP66.

With suitable couplings or gear wheels, the encoders can be directly integrated into plants and machines. The encoders’ control unit enables users to set its position as well as the preferred zero position in the machine.

Posital introduces a magnetic rotary encoder with hollow shaft design

September 19, 2011 By Motion Control Tips Editor Leave a Comment

Posital (www.posital.com) has announced that its Magnetocode (MCD) absolute rotary encoders now features a new hollow-shaft variant of the MCD encoder, making the devices easier to mount on shafts up to 20 mm in diameter.

Featuring excellent accuracy, adaptability and reliability, the new devices are offered with digital or analog electrical interfaces. With measurement technology based on a Hall-effect sensor and a rotating magnet, the analog models make a great alternative for traditional potentiometers as it provides superior longevity, reliability and accuracy.

Unlike potentiometers, these new encoders do not run the risk of losing accuracy due to surface contamination or wear since there is no contact among its components. The encoders also offer flexible range-setting feature that allows the installer to “teach” the device the potential mechanical motion’s limits during operations. When the limits have been established, the device will instantly self-calibrate to enable the full range of electrical output to exactly match the mechanical movement’s full range.

This results to a remarkable improvement on the control system’s overall accuracy. To simplify the setup, the analog-output models also provide LEDs and buttons on its casing.

The MCD encoders’ digital outputs include CANopen, serial (SSI) and DeviceNet. These tough MCD encoders feature heavy-duty enclosures to protect the measurement components from dust, shock and vibration, as well as mechanical loads and moisture (up to IP 69K ratings). The hollow-shaft models also feature permanently lubricated brass and steel gear-set for a trouble-free and long service life.

POSITAL offers new interface options for rotary encoders

July 8, 2011 By Motion Control Tips Editor Leave a Comment

POSITAL (www.posital.com) has announced that its Optocode (OCD) absolute rotary encoders now come with a new combined interface that allows simultaneous communication of both incremental and absolute position data. The company’s new interface is specifically developed to deliver cost effective and robust point-to-point communications between various kinds of programmable logic controllers (PLC) and encoders.

Utilizing the synchronous serial interface (SSI) standard, the new interface relays absolute rotary position information to the PLC. While the shaft is rotating at a maximum speed of 16,384 pulses per rotation, the encoder also sends a series of electronic pulses. An optional index pulse can also be transmitted once every complete rotation.

Meanwhile, the incremental pulses can be transmitted via a push/pull connection or over an RS-422/485 link. Responding to a request from the controller, the dual-personality encoders offer access to absolute rotary position information while accurately measuring the rotational velocity in real-time and making it suitable for monitoring rotating machinery or for motor control applications.

These encoders also offers other new features such as optimized diagnostic reporting through the SSI connection or through case-mounted LED’s, and an optional case-mounted push-button that enables the operator to re-set the absolute position readout’s zero-position (datum).

The new OCD encoders keeps the previous generation devices’ best features, including accuracy, highly effective shaft and connection seals (up to IP66 protection), precision (up to 216 steps per turn) and single- or multi-turn capabilities. Available in hollow, solid and hub shaft variants, the units can be supplied with a cable exit or a connector.