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Failsafe RTD/Thermocouple Modules for ET200M or ET200isp

Created by: dshha at: 1/20/2012 1:01 AM (7 Replies)

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1/20/2012 1:01 AM	Rate (0)
dshha Advanced Member Joined: 6/15/2010 Last visit: 8/1/2024 Posts: 31 Rating: (1)	Hi there, Wehave a requirment where we mayhave to use ET-200M fail-safe IO modules for RTD or thermocouples. Just wondering if we can connect either RTD or T/C to suitable AI module which is fail-safe? Our initial search shows that the RTD/TC modules are not available in fail-safe version.Could you please advise me urgently if we can achieve this. This modules has to be installed in REMOTE IO panel which is in Zone 2 Hazardous Area which means it should have instrinsically safe internal barriers (galvenic isolation). If above cannot be achieved then I think the alternative is to use ET200isp, can someone tell me RTD or T/C modules are available in ET200isp fail-safe version? Waiting for your suggestions. Let me know in case of any Qs. Cheers, D

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1/20/2012 1:24 AM	Rate (0)
dchartier Grandmaster-Expert Joined: 9/27/2006 Last visit: 1/19/2025 Posts: 12330 Rating: (2700)	Hello D; I am just curious, but yourdescription would seem not to require a failsafe module, but a hazadous zone (Ex)module (for explosive areas). Just to examine the possibilty, maybe you could look at the following manual; it shows how these Ex modules for S7-300 and ET200M can be connected to TCs and RTDs, and what certifications they are covered by. SIMATIC Automation systems S7-300, ET 200M Ex I/O Modules The SIMATIC S7 Ex modules have the following FM licenses: • Class I, Division 2, Group A, B, C, D Tx; • Class I, Zone 2, Group IIC Tx Therefore, the modules can be used in areas that contain volatile flammable liquids or flammable gasses which are normally within closed vessels or systems, from which they can only escape under abnormal operating or fault conditions. The license applies to all test gasses. A surface temperature no greater than 135 °C (T4) occurs at ambient temperatures of 60 °C. Hope this helps, Daniel Chartier

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1/20/2012 1:35 AM	Rate (0)
dshha Advanced Member Joined: 6/15/2010 Last visit: 8/1/2024 Posts: 31 Rating: (1)	Thanks a lot Daniel for your prompt response. This project has requirement of failsafe PLC with minimum SIL2so the standard PLC (without failsafe version) optionwill not be helpful. Cheers, D

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1/20/2012 8:03 AM	Rate (0)
dshha Advanced Member Joined: 6/15/2010 Last visit: 8/1/2024 Posts: 31 Rating: (1)	Hi, I've posted and eagerly waiting for the response. Hope someone helps with solving this very important issue. If you know someone else who could help me, please forward. Cheers, D

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1/20/2012 3:48 PM	Rate (0)
H-H Platinum Member Joined: 7/2/2008 Last visit: 9/30/2024 Posts: 928 Rating: (309)	Hellodshha, Unfortunately Siemens doesn't have a SIL2/3 module that supports RTD/TC directly. You have said that you require an isolated safety barrier. So, you should buy a SIL2 intrinsically safe signal converter like thisoneof P+F. If you require redundant I/O (sometimes in SIL2) then you should buy something similar to thisone. In both cases ET200iSP F-module won't be of much benefit and ET200M F-module will be good. I'm sure you can find the same in MTL or TURCK or Weidmuller. Best regards. H-H

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1/21/2012 10:29 PM	Rate (0)
dshha Advanced Member Joined: 6/15/2010 Last visit: 8/1/2024 Posts: 31 Rating: (1)	Thank H-H, I've had this option in my mind as the last one to go for. One question though, is it necessary to have I/O modulechosen as SIL2 if you've the processor already as SIL2? My understanding is that when you've SIL2 requirement forsystem, there is no other option but to choose allsystem components (such as I/Omodules)that are SIL2 rated and that means I'll have to go for S7-315F with ET200M-F modules with P+F SIL2barriers. What are your thoughts on this? Cheers, D

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1/31/2012 8:08 AM	Rate (0)
H-H Platinum Member Joined: 7/2/2008 Last visit: 9/30/2024 Posts: 928 Rating: (309)	Deardshha, I'm really sorry for my late reply. dshha One question though, is it necessary to have I/O modulechosen as SIL2 if you've the processor already as SIL2? Yes you have to use SIL2 I/O modules dshha My understanding is that when you've SIL2 requirement forsystem, there is no other option but to choose allsystem components (such as I/Omodules)that are SIL2 rated and that means I'll have to go for S7-315F with ET200M-F modules with P+F SIL2barriers. What are your thoughts on this? Yes, Everything should be SIL2 even transmitters and actuators have to be SIL certified. Best regards. H-H

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1/31/2012 9:12 AM	Rate (0)
Rated X Posts: 1547 Rating: (129)	Have you ever thought about using a DP/PA coupler in your PROFIBUS and then failsafe PA transmitters (F-communication also is possiblefor PROFIBUS PA)? Because of easy cabling in some configurations PA can compensate high equipment prices.
Rated X Posts: 1547 Rating: (129)
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