4/6/2016 4:50 PM | |
Posts: 8946 Rating: (999) |
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4/6/2016 7:30 PM | |
Joined: 9/27/2006 Last visit: 9/20/2024 Posts: 12282 Rating: (2684)
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Hello Eric; You refer to SIL and PL levels, which are definitions of machine safety introduced by international standards. The latest is EN ISO 13849-1, which defines PLs and is itself an evolution of ISO 62061, which introduced SIL levels, still used in many applications. These standars not only use various grids tpo evaluate safety risks and determine how satety functions will be used to attenuate them, they also determine a series of component types accepted to integrate these safety functions. Basically, this means that you cannot use the hardware you are describing and propose them to carry out a SIL or PL application; this is not only a manufacturer's way to force you to purchase more expensive material and software. When you tell a client you are implementing safety functions to SIL 2 or 3, or PL c, you are contractually obligated and liable for any mishap, injury or death that can occur on the proposed machine. So equipment and programming must be chosen to respect the international guidelines. Look at the attached screenshot for an idea of the minimum required hardware required to attain various safety levels. Basically, you should only think of developing a safety application using a Safety controller (for Siemens, that would be a F-CPU, such as a S7-315F-2PN/DP or a Sirius Safety relay) with F-IO and a Safety program (such as the Distributed Safety software). Note that a Safety CPU can run (in parallel to the safety functions for a project requiring safety IO) a normal program controlling normal I/O, so you can control all aspects of a process in a single controller. A Safety CPU not only runs a Safety program using Safety IO; it has very strict monitoring functions to evaluate the status of the Safety IO, imposed by the safety standards mentioned above. Appendix A of the Safety Engineering manual suggested below describes these monitoring times and functions. I suggest you look at the following documents, describing the software and hardware proposed by Siemens so that you may start developing an expertise in safety engineering with Siemens. SIMATIC Industrial Software Safety Engineering in SIMATIC S7 https://support.industry.siemens.com/cs/ww/en/view/12490443 SIMATIC Industrial Software S7 Distributed Safety - configuring and programming https://support.industry.siemens.com/cs/ww/en/view/22099875 Documents on the S7-315F-2PN/DP SIMATIC Automation System S7-300 ET 200M Distributed I/O Device Fail-safe signal modules https://support.industry.siemens.com/cs/ww/en/view/19026151 And finally some presentations of Siemens Safetycomponents: The Way to safe Machinery (Video) https://support.industry.siemens.com/cs/ww/en/view/109481791
The Safety System for Industry (ch. 7 for Safety Controllers)
https://support.industry.siemens.com/cs/ww/en/view/28813929
Hope this helps, Daniel Chartier
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Last edited by: dchartier at: 4/6/2016 7:33:28 PMLast edited by: dchartier at: 4/6/2016 7:59:59 PM |
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