Tech Tips June 2006

By Control Engineering Staff March 22, 2007

June 27, 2006

TECH TIP OF THE WEEK:

Benefits of machine-to-machine (M2M) data capture

Machine-to-machine (M2M) communication is a rapidly evolving arena. This technology—among other things—is redefining the scope of customer relationships and business operations, because companies can ensure better and more appropriate customer service by anticipating and responding to problems as (or before) they arise.

Companies are looking beyond opportunities from new product sales, aiming to capitalize on benefits of being able to better shape customer relationships. By tracking a device through its lifetime, a company can acquire significant data and insight into product performance in different scenarios and stages, customer needs, and customer behaviors. This information can yield optimized technologies and services for customers, significant profit gains for companies involved, and improved relationships between companies and customers.

Synergy from combining M2M technology with device networking adds an unprecedented level of intelligence to business, helping to reduce maintenance costs and open opportunities for additional revenue streams. Here are some benefits of applying M2M device-server technology:

Companies can be alerted to equipment failures before they happen, saving time and cost through proactive maintenance. An electronic device—such as a security system, commercial refrigeration unit, or medical diagnostic equipment—can incorporate technology to perform self-diagnosis and self-healing.

Service technicians in a central location can determine status and operating conditions of equipment located anywhere.

Unnecessary service calls can be eliminated. Enabled with device-networking technology, equipment can connect to a network, monitor itself, and ensure that it’s functioning properly. Often, when something is wrong, a simple setting or switch adjustment is all that is required. When something irregular is noted, it frequently can be diagnosed and repaired over the network, avoiding an on-site trip.

If a service call is needed, technicians know exactly what needs to be repaired and have the necessary equipment and parts when they leave the service center.

Organizations can increase customer satisfaction and generate an additional revenue stream through up-sale marketing offering remotely managed, value-added field services.

Source: Control Engineering, April 2006 Inside Machines section, ‘ Machine-to-Machine Data Capture .’

June 20, 2006

TECH TIP OF THE WEEK:

Using redundant equipment is widely recognized as an approach to attain high reliability in a system. However, implementing redundancy is not always as easy as it may seem. It takes more than simply paralleling the outputs of two or more power supplies to have a redundant power system that will function as intended. Here are some considerations to keep in mind when working with a redundant power system, according to Acopian Power Supplies:

Use an isolation diode in series with the output of each power supply. This is required for two reasons. It avoids the possibility of shorting the combined output by a shorted supply and it prevents current from one supply flowing back into another and causing a ‘reverse bias’ malfunction. However, keep in mind that using diodes introduces a significant voltage drop in the supply output. For example, a 5-V output might drop to 4 V. Using Schottky diodes can in some cases mitigate the diode drop, but it must still be considered.

Provide voltage in the supply equal to the voltage sum required across the load. This includes the diode voltage drop plus drops in the wiring—under worst-case conditions (usually, low line and maximum load current). A typical power supply can compensate some voltage drop in the wiring (say, up to 1 V or so), but may not be able to compensate the diode drops as well. The supply also must have the desired load voltage within its adjustment range.

If you’re using remote sensing to regulate voltage across the load, the problem may not be solved simply by stepping up to a supply with a higher nominal output voltage (going to a 6-V supply from a 5-V supply), since the supply’s sense lines would then try to maintain a nominal 6 V across the load.

Power supplies used in redundant applications must always be equipped with fast-acting overvoltage protection. This important factor ensures that output voltage can’t go much higher than nominal. Power supplies don’t always go low when they fail; voltage can instead go high—50% or more in some cases—and ‘fry the load.’

Replacing an inoperative power supply while the system remains in operation requires that each power supply have a separate ac input switch. This provision enables deactivation of the inoperative supply’s wiring without affecting the other(s).

Similarly, it must be possible to disconnect the inoperative supply and connect the replacement quickly and easily, so insulated connectors that can be easily pulled apart should be used in the wiring to each supply. Also, the supplies should be mounted so they can be easily and quickly removed and replaced. Use of thumbscrews for mounting is one way to do this, which also eliminates the need for tools.

Source: TechTip 1: ‘Considerations When Paralleling Power Supply Outputs for Redundancy.’ www.acopian.com

June 13, 2006

TECH TIP OF THE WEEK:

How to keep an automation system running on budget—Part 2

Industrial automation products eventually become obsolete. It takes careful planning and proper maintenance, but end-users can prolong operational life of their automation systems for many years, continuing to obtain return from their investments. Here are some additional tips from system integrators who know how to keep an automation system running on a budget. A previous set of tips was given in last week’s ‘Tip of the Week’ (06/06/06).

If it ain’t broke don’t fix it Upgrade to a new version only if it fixes an existing problem or provides a ‘must-have’ feature. Don’t be tempted to buy every upgrade or enhancement. If the automation system is working well enough, leave it alone. If new software versions come out every few years, consider skipping a version or two.

Standardize Choose open-industry standards or proven technology sufficiently widespread to be a de facto standard (for example, IEC 61131-3 programming tools, Ethernet communications, Microsoft Windows operating systems). Make the most of your spare parts inventory; use a limited number of brands for replaceable parts.

Modularize Simplify parts replacement by designing hardware and software as a set of functionally independent modules, connected with well-documented interfaces. Ensure that panels, consoles, I/O racks, etc. are built with enough space to remove one part without significant overall disassembly.

Seek an outside perspective End-users are often unaware that some of their equipment is no longer repairable or replaceable. Have a third party assess the existing system’s exposure to obsolescence and document the risk areas. Don’t wait to do this until a program crashes or a part fails.

Check out alternative sources Don’t give up on an existing automation system just because it’s old. Even after key components have become extinct, many automation systems can be maintained thanks to e-Bay and third parties specializing in replacing, repairing, and stockpiling obsolete hardware.

Source: Control Engineering, Feb. 2006, Back to Basics, ‘ Obsolescence is no defense .’

June 6, 2006

TECH TIP OF THE WEEK:

How to keep an automation system running on budget—Part 1

Industrial automation products eventually become obsolete. It takes careful planning and proper maintenance, but end-users can prolong operational life of their automation systems for many years, continuing to obtain return from their investments. Here are some tips from system integrators who know how to keep an automation system running on a budget:

Stockpile spare parts During the first few years of operation it should become obvious which parts of the automation system fail most often. Buy plenty of spares, especially if the vendor has introduced new versions that are not backward compatible.

Choose reliable vendors Many automation products have become commodities with very similar features. If all else is equal, buy from vendors with a track record supporting legacy systems. A little-known vendor with a short history may not be around in 10 years to help with upgrades; but if the technology is superior, it might be worth the risk.

Learn from history Remember the effort and rework required for past upgrades, especially the installation of new software versions. Stick with system integrators that have proven to be reliable on such projects and with vendors that have provided pain-free migration paths to their latest technology.

Start with the best Avoid buying products that are nearing obsolescence. Life cycles vary, but any technology on the market for over 10 years is likely to be supplanted in the near future. Still, be sure that the latest technology has at least enough of a track record to demonstrate its effectiveness.

Plan ahead, but not forever Consider the expected life span of the process being automated. If it is unlikely to be operational for more than a few years, there’s no need to invest in an automation system that will outlive it. Yet, processes requiring high reliability-and-availability ratings should not be run with outdated or dilapidated automation components.

Additional suggestions will be provided in Part 2, in the next ‘Tip of the Week.’

Source: Control Engineering, Feb. 2006, Back to Basics, ‘ Obsolescence is no defense .’