TUV AK6 APPROVAL

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Thread Starter

S.B.Gujarathi

I would like to know that basis on which TUV AK6 approval is given & also care I should take while selecting such PLC.
 
G
The hardware and software requirements for Application Class 6 are defined in DIN/VDE 0801, a German standard. TUV will also certify products to the more recent IEC 61508 standard as well. The requirments are many and varied. There are a dozen or more vendors that have hardware certified to that level, ranging from simplex to triplicated. How you select something is also
varied (programming language, local support, connectivity, level of redundancy, range of I/O modules actually certified, speed of response,
etc.), although naturally each vendor will tell you their system is 'best'. ;-) Some will even argue the benefits of which TUV does the certification.

Paul Gruhn, PE, CFSE
Siemens, Houston TX
 
P
The hardware and software requirements for Application Class 6 are defined in DIN/VDE 0801, a German standard. TUV will also certify products to the more recent IEC 61508 standard as well. The requirments are many and varied. There are a dozen or more vendors that have hardware certified to that level, ranging from simplex to triplicated. How you select something is also
varied (programming language, local support, connectivity, level of redundancy, range of I/O modules actually certified, speed of response,
etc.), although naturally each vendor will tell you their system is 'best'. ;-) Some will even argue the benefits of which TUV does the certification.

Paul Gruhn, PE, CFSE
Siemens, Houston TX
 
It has to do with the potential risks in case of an accident. SIL-3 or TUV AK6 systems are required for processes in Ex-zone area 1. At the moment the Siemens S7-400F is most favourite, because it allows Control- and Safeguarding in one system, withoutany consequences to the SIL-3 level (TUV-AK^6) In this case you don't need two systems. All can be programmed in the SIL-3 certified S7-400F.
 
> It has to do with the potential risks in case of an accident. SIL-3 or TUV AK6 systems are required for processes in Ex-zone area 1.>

If "Ex-zone area 1" stands for electrically classified hazardous Zone 1 area (ie. IEC 60079-10 or NEC Article 505), this is mixing protection
concepts. Area classification has nothing to do with requiring SIL 3 or TUV AK6.

In regards to the main question:

> > I would like to know that basis on which TUV AK6 approval is given &
> > also care I should take while selecting such PLC.

The basis for TUV AK6 approval is the German Standards DIN 19250 and DIN/VDE 0801. Also, while there is no direct conversion between AK and SIL, SIL 3 generally includes AK5.

German standard DIN V 19250 ("Basic Safety Evaluation of Measuring and Control Protective Equipment") defines eight "AK" classes (1 to 8). AK = Anforderungsklasse = Requirement Class (RC). These ratings are used in DIN V VDE 0801 (for computers/PLC's), and more generally, in (draft) DIN 19251.(Source: TUV)

I also would refer you to these web sites:

"tuvasi.com/faq-fs.htm":http://tuvasi.com/faq-fs.htm
"www.tuv-fs.com/plclist.htm":http://www.tuv-fs.com/plclist.htm
"www.tuvasi.com/index.htm":http://www.tuvasi.com/index.htm
"www.triconex.com/resourcecenter/sis/standards.asp":http://www.triconex.com/resourcecenter/sis/standards.asp

Bill Mostia
=================================
William(Bill) L. Mostia, Jr. P.E.
Partner
exida.com, LLC
Excellence in Dependable Automation
[email protected](b) [email protected](h)
www.exida.com 281-334-3169
These opinions are my own and are offered on the basis of Caveat Emptor.
 
J
SIL-3 or TUV AK6 approvals apply to functional safety and have nothing to do with processes in Ex-zone areas.

Do not confuse functional safety with intrinsic safety etc. they are two very different things.

Most SIL/AK systems cannot be placed in a hazardous area.

Most devices that can be placed in a hazardous area have no SIL/AK rating.

SIL/AK I would say is given based on the ability to detect failures and subsequently shut a process down safely.

Exi/Exd etc. certification is given based on the method and ability to prevent ignition of flammable stuff.

Jonas
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[email protected]
www.smar.com
 
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