A new angle on rotary feedback

steelindustryTransporting hot materials (ex. steel slabs) from one location to another via a walking-beam is common place in steel manufacturing. In the past, rotary encoders have typically been used to provide the precise feedback of rotary movement for these types of applications. However, optical encoders are prone to failure in harsh environments. Steel mills utilizing walking-beams for material handling have plenty of dirt and particulates in the air as well as produce high shock and vibration. All of these would contribute to an overall harsh environment which would shorten the life of an optical encoder.

Precise position checking and the continuous adjustment of rotational movements are extremely important on the walking-beam. Inclination Sensors are ideally suited for these exact tasks. With contact-free angle measurement, they guarantee maximum precision when the slabs are being transported. Inclination Sensors do not need mechanical coupling in contrast to rotary encoders, are compact and robust, and measure the deviation from the horizontal on an axis of up to 360°.
inclination-axisDowntime at a Steel Mill can cost up to tens of thousands of dollars per hour. The next time you need you have an angular measurement application in such harsh environments, you may want to consider an Inclination Sensor. It will surely be up to the task!

For more information on Balluff solutions for the metallurgy industry, start here.

For more information, visit www.balluff.com.

Angle Sensing & Tilt Detection Solutions

When an application calls for angle sensing or tilt detection there are a few choices including fluid based and MEMS technology Inclination sensors. For this blog entry we will focus on the MEMS technology. MEMS offerings have the option of one or two axis with up to 360° of measuring range. They provide an easy means of directly detecting positions without making contact enabling continuous feedback of rotational movements along the axis. The precise position control and continuous positioning of rotational movements are critical in many applications making them reliable solutions where accurate positioning is a must.

Sensors based with the MEMS technology operate by taking a capacitance differential and converting it to an analog signal. This analog signal is relative to the angle of the sensor in the application. The compact housing sizes are also a great feature offering various mounting options for a wide range of applications.

constructionequipmentMEMS Inclinations sensors can be used in various types of applications. Inclination sensor typically have  robust IP67 ratings making them ideal for tilt protection for cranes, hoists, tractors, expandable mechanical arms and other types of mobile agricultural machines. The Inclination sensor controls and monitors efficient operation verifying the correct positioning needed for reliable operation.

It is not uncommon to see MEMS style inclination offerings used in the renewable energy market. You can commonly see applications where inclination sensors are mounted directly to a rotating shaft to provide angel feedback for Fresnel Solar Panels.

inclinationsensorProduct Features:

  • Compact housing
  • Low temperature drift
  • Contact Free operation
  • High repeat accuracy
  • Precise analog measurement
  • Shock resistant


  • Cranes
  • Hoist/Boom Trucks
  • Lifts
  • Mobile Implements
  • Shaft rotation
  • Solar Power

For more information on inclination sensors visit www.balluff.us.

Solar tracking systems and sensors

Over the last few years there has been a lot of discussion on how we will meet the global energy demand in the future. And what will be the technologies to generate it? In the end it all comes down to the levelized cost of electricity (LCOE), which is the sum of all costs of a power plant divided by the total electricity that is generated over the plant’s lifetime. All companies in the renewable energy industry focus on reaching lower LCOE compared to conventional power generation (especially gas). Their biggest advantage is that there are no costs for fuel (sun light, wind, water).

solarpanelsLet’s take solar power as an example. Principally there are two ways to use the sun light: First it can be converted directly to electricity (photovoltaics). Second, it can be used indirectly by generating thermal energy (concentrated solar power). In order to reach higher efficiency solar trackers are used to orient photovoltaic panels, reflectors, or mirror towards the sun. On the other hand they add costs to the system. Therefore it must be carefully calculated whether a tracker (single or dual axis) is required or not (fixed installation).

solarpanels2Single axis trackers are used to position photovoltaic panels, parabolic troughs or linear Fresnel collectors from east to west on a north to south orientation. Depending on the required tracking accuracy different sensors are used for this task. As most of the photovoltaic trackers use electric linear actuators, very often inductive sensors are installed on the actuator for position feedback. They are cost optimized and are a standard feature in the actuators. Another option is to use inclination sensors that are directly mounted on the rotating shaft to provide angle feedback (e.g. in linear Fresnel plants). As inclinometers are mounted on the moving part, there is cable wear that could lead to failure over time. For high end tracking, as is required in parabolic trough plants, magnetic tape systems are used as rotary encoders. A magnetic tape is mounted around the shaft and a sensor head is installed on the frame of the tracker. The sensor counts the pulses accurately and provides continuous position feedback without any wear.

solarpanels3Dual axis trackers are used to position concentrated photovoltaic (CPV) panels, parabolic reflectors (dish) or mirrors (heliostats). Especially in central receiver plants high accuracy is required. They need high temperatures and therefore have to focus lots of light on a central receiver on top of a tower in the middle of the heliostat field. As there is an azimuth and an elevation axis, two position feedback systems are required. The elevation angle could be solved with an inclinometer, but this does not work for the azimuth position.  Again, the position could be measured with embedded rotary encoders directly on the drive. But there is again backlash, and accuracy is of highest importance as heliostats could be one mile away from the central receiver. Magnetically coded position and angle measurement systems can be mounted on both axis (azimuth and elevation) and provide direct position feedback with highest accuracy.

More information can be found in this brochure about power generation. http://asset.balluff.com/std.lang.all/pdf/binary/861522_162563_1305_en-US.pdf

Special thank you to Bernd Schneider, Industry Manger – Balluff GmbH for contributing to this post.