Benefits of integrating safety into drives

April 7, 2009
With the increasing strains in the economy, engineers are faced with finding ways to lower costs, reduce maintenance, and streamline operations. 
Encompassing safety into an integrated automation platform can provide a seamless integration that delivers real benefits to the bottom line, including reduced expense, less use of space, and more reliable safety systems when compared to those offered in the recent past. To achieve this, it took some modernizing of standards, but also took evolution of the automation products and careful engineering to come up with a solution that is reliable enough to be trusted with machine safety. Sometimes changing restrictions can make your life easierWhen PLCs first entered the market in the 1970s, they were only smart enough to perform simple sequences. If the unit got into looped sequence, it was difficult to stop. So the NFPA79 had to ensure designers added electromechanical shutdown devices in addition to the PLC to protect people from the PLC.  Over the years the standard PLC capabilities improved dramatically and a new class of Safety PLC was developed that eliminated the safety risk in the original designs.  In 2002, the NFPA 79 standard was revised to allow listed safety PLCs to function in the safety capacity bringing the design of automation control and safety shutdown together. The 2002 version of NFPA 79 standard still required an electromechanical device as the element for final removal of power in all cases.   This held back the introduction of safety rated drives since they achieve safe control with redundant electronic disconnects inside the drive and prevented safety design from using the many benefits that come with the new drive technology .  The latest revision NFPA 2007 has removed the restriction and allows safety rated drives to take advantage of the high reliability of electronic devices. The new Siemens safety design creates a seamless safety architecture including the driveThe integration of safety into the drive requires some fundamental differences in the internal drive design, like adding control reliable disconnects to the low voltage power that runs the rotational speed output of the drive.  That's why Siemens started from scratch and designed safety drives from the inside out, rather than trying to modify an existing design. The key is that truly integrating safety into the system design provides a simplified seamless architecture because of the common safety concepts and the connection of the drive on the PROFISafe safe rated bus with the safety PLC.Siemens safety drives are designed with the overall safety design architecture built right in. The whole system is modular, so it's easy to install. The look and feel of the configuration and programming is the same, so it's simple to just add modules in a "plug and play" fashion. No other safety drive system has this level of smooth integration with the automation system allowing only bus connection to the drive for both automation speed control and safety.  The bus system is expanded by the PROFIsafe protocol for transmitting safety-oriented data. The connection to the standard and safe modules is made via open Ethernet PROFINET or via PROFIBUS, fieldbus technology with this embedded PROFIsafe protocol, providing the choices you desire while maintaining one consistent design.  Safety-related and standard communications are now possible over only one standard bus cable. Integrating safety in your design will eliminate the isolated safety system and simplify the safety related design and operation of the machine, resulting in improved efficiency and increased profits.Energized stops and safe speed control increase efficiency and improve profitsWith safe motion and limited speed, your production can continue
Siemens seamless architecture delivers a drive that is more intelligent. It is monitored to ramp down and not to exceed safe speeds. You can take the drive to slow speeds without stopping the drive. This leads to huge improvements in productivity because the drive is always energized rather than going to a complete stop. You get safety without completely powering down. This means line startups are faster and smoother. It's achieving safety without "stopping. "Retaining drive power gives improved diagnostics and faster repairsPowering down the drive using bulky, expensive three-phase contactors or other older methods caused lost production time and conflicts between production and safety requirements.   With today's safety rated drive troubleshooting and repairs take less time.                                                                                    Reduced wiring and reduced engineering saves money
Siemens safety drives deliver a number of advantages and benefits for the OEM and the end user. For the OEM, with the Siemens Safety Drives you no longer need bulky, expensive three-phase contactors.  And, if you are controlling a large motor you know that its contactor is not an insignificant piece of equipment. Not only can you eliminate the contactor, you no longer need the labor or cabinet space - and you achieve simplified compliance.   Additionally, you'll have faster, easier and less costly wiring; faster certification; fewer and smaller enclosures; and, you can eliminate hardwired logic design. The impact: lower engineering time and cost.End users will also see improved productivity and compliance. End users will enjoy more product output per machine with fewer components to fail. Because TIA shows operator fault location, you'll have much better diagnostics. Easier troubleshooting means you'll be able to correct problems more quickly. There's less machine downtime for improved throughput, resulting in significantly less maintenance for lower costs and overall improved operation.  And, perhaps most importantly, you'll be more effective at preventing accidents.Scalable and modular to meet your application needs with a complete range of drive sizes and selectable controller size
Siemens offers a complete line of drives, switches and sensors to compliment its safety drives. This system is infinitely scalable and the modular design let's you add or subtract modules as your processes change. Get this all in one common architecture - with safety built in.Click here for more information.

Would you like a Siemens Technical Specialist to contact you for a Free Automation Assessment and discuss cost savings for your application? Click here.

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