When it comes to Industrial Ethernet fieldbus protocols, it can quickly become confusing to understand how they work and what some of the differences are. We as engineers get excited about the latest and greatest hardware, but we must remember that behind the scenes is a communication network that is helping define the performance of that hardware. In order to better understand the impact that a communication network can have on an industrial control system, let’s speak a bit to Ethernet POWERLINK. POWERLINK is frequently employed by IFP Automation on systems as our standard when utilizing B&R hardware for optimal system performance.

What is the difference between standard Ethernet and Industrial Ethernet?

One of the major differences between standard Ethernet protocol (or TCP/IP) and Industrial Ethernet is collision avoidance. The data transfer in standard Ethernet may have irregular delays, which is unacceptable when trying to achieve hard real-time performance. In circumstances where irregular delays can be acceptable (office computers, printers, serving web pages, etc.), Ethernet TCP/IP is perfectly fine. But in industrial motion control applications, a solution for hard real time communication is needed.

Because of this, an Industrial Ethernet protocol must use preventative methods that avoid such collisions. The data transmission must also occur within a very specific window of time, which is referred to as jitter. Soft real-time performance can tolerate a limited amount of jitter and may have cycle times of up to several hundred milliseconds. Soft real-time performance could be used for applications such as temperature monitoring. Hard real-time performance on the other hand would be used for applications such as motion control, and commonly requires sub-one-millisecond cycle times. (more…)

The answer to that question all depends on the customer’s application.  Is the system more complicated than just turning on and off a simple solenoid valve?  Does system control need to be variable depending on the situation or scenario?  Does the customer need to vary velocity on the fly?  Does the customer need to position a load precisely on a dime (or tighter tolerance than that)? Does the system need to provide a constant force to finish making the workpiece?  These are just a few of the questions that a hydraulic system designer must ask himself when deciding on what technology is needed to achieve the perfect solution for his customer.  If the hydraulic system designer answered, “yes,” to any of the questions above, there are two technologies that could save the day: open loop and closed loop hydraulics.

In the simplest form, an open loop system has an input that is not dependent on the output.  For example, the motion controller/PLC sends a command signal to a proportional directional control valve and this command signal does not change based on whatever is happening downstream in the hydraulic circuit.  There is no feedback coming back to the motion controller/PLC.  Open loop systems are typically used for velocity type applications.  One could almost compare it to using the accelerator pedal in a car.  The harder the pedal is pushed, the faster the car goes.  The less the pedal is pushed, the slower the car goes.  The spool in a proportional directional control valve can proportionally slide open to go faster and proportionally slide closed to go slower, depending on the command signal to the valve from the motion controller/PLC.  

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For many years, industry favored flash memory due to its lack of rotating parts and resulting robustness against vibrations and other factors. In response to the frequent questions regarding data storage media, this blog will provide a summary of the most important issues. I will outline four main types of data storage media, and some differences between them. First, since all the options outlined are based on flash technology, I wanted to give some insight into the difference between two ways to store flash memory, Single Level Cell (SLC) and Multiple Level Cell (MLC). Then, I will start with the grandfather first, CompactFlash. This card, known as CF for short, gave birth to the CompactFast card (CFast), in both an SLC and MLC format. Finally, with the price of SSDs coming down, this has become a viable option.

SLC vs. MLC

For a long time, MLC-based flash drives were not suitable for industrial use because they allow a significantly lower number of write/erase cycles. This restriction was overcome by the development of intelligent wear leveling, which distributes write operations evenly across all available flash cells. SLC flash drives have a longer lifespan than MLC drives, but are also considerably more expensive.

The main difference between SLC (Single-Level Cell) and MLC (Multi-Level Cell) technology is in the way that data is stored. SLC flash drives store one bit per cell, while MLC drives are able to store two bits per cell.

MLC products have a clear price advantage, yet score lower when it comes to endurance (i.e. long-term life expectancy) compared to SLC products. MLC memory generally displays a loss of data retention (data storage when powered off) over time – from an initial 10 years to 1 year after the maximum number of write/erase cycles – which is not likely to be a problem for most end customers.

The biggest drawback compared to SLC memory is the significantly lower number of specified write/erase cycles per flash block. This factor has a direct impact on the specified TBW (terabytes written), so MLC products are not ideal for writing-intensive applications. If the specified TBW is not sufficient, it is possible to select a larger storage medium. This option is possible because the firmware used ensures that wear is distributed evenly across the blocks, as described above. Additionally, SMART functions can read out the average erase count per cell. This allows customers to monitor their application over a given interval and then estimate the predicted lifespan. Access to the SMART values is provided by freeware tools such as CrystalDiskInfo (http://crystalmark.info/?lang=en).

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Traditionally speaking, belted drive actuators have only been seen as horizontal solutions in applications where single or multi-axis Cartesian systems are utilized. That time has ended with the introduction of Rollon Corporation’s SMART series actuator.  This steel-reinforced belt drive actuator is able to achieve the reliability and performance required from a ballscrew system, but with a lower cost, lower noise, higher speed, and more simply  constructed device.  The anodized aluminum bodies of these devices can deliver the right combination of high mechanical strength and reduced weight for a variety of applications.

What follows is real application feedback from machine builders who note several ways that these actuators have benefitted their applications.

Open Design.  SMART actuators make maintenance easy. Since they don’t have any caps or coves, engineers can directly reach any wear components that need repairing.

Mount Orientation.  This series comes with a symmetrical drive head, allowing machine builders to quickly change the actuator’s motor mount orientation without a new part number or any actuator reworking.  Since SMART actuators are more flexible and convenient, machine builders know that, when making design changes, their motor will properly fit.

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IFP would like to thanks to everyone who helped make this years ride a success. We started out with a team goal of $6,000, which we were able to meet with your help and support! This years impact to the American Diabetes Association was $6,176, and we still have a few more donations still trickling in. Team IFP was the 14th highest raising team this year, out of 144 teams and 1,262 riders. In comparison, last year we raised $2,641, so all of our supporters greatly helped us more than double what we could contribute to the American Diabetes Association.

Thank you as well to all of the other 1,262 riders who participated, as well as everyone who supported the ADA at this years Tour deCure!

Next years ride is scheduled for June 18th 2016. We hope to have even more riders next year. If you are interested in cycling at the Indy Motor Speedway, please consider joining us. Thanks again!!

IFP – 2015 Indiana Tour de Cure Team Page: http://ow.ly/LYfMs