×
INTELLIGENT WORK FORUMS
FOR ENGINEERING PROFESSIONALS

Contact US

Log In

Come Join Us!

Are you an
Engineering professional?
Join Eng-Tips Forums!
  • Talk With Other Members
  • Be Notified Of Responses
    To Your Posts
  • Keyword Search
  • One-Click Access To Your
    Favorite Forums
  • Automated Signatures
    On Your Posts
  • Best Of All, It's Free!

*Eng-Tips's functionality depends on members receiving e-mail. By joining you are opting in to receive e-mail.

Posting Guidelines

Promoting, selling, recruiting, coursework and thesis posting is forbidden.

Students Click Here

Level switch as part 2oo3 voting

Level switch as part 2oo3 voting

Level switch as part 2oo3 voting

(OP)
Hi

Is it a good idea to use level switch as part of 2oo3 voting where the other two devices are transmitters.. in this case , if the switch fails, we will not know and we will end up having two devices (2oo2) configuration.. is this correct ? Can anyone add more comment from experience on this type of configuration please

Thank you

RE: Level switch as part 2oo3 voting

I don't think it provides as high of a level of redundancy. A pair of transmitters can indicate trouble if the sensor values deviate. 3 transmitters will tell you which one is defective so that value can be ignored. A switch provides no indication of proper functionality other than a heart beat in some cases.

RE: Level switch as part 2oo3 voting

The 2oo3 Voting With diverse Devices is a very good idea to minimize common causes which affect the Safety integrity Level(SIL). however, the Switches are dummy and do not have any diagnostic coverage and can fail dangerous and can not be detected. by using all three transmitters you can implement deviation alarms and detect out-of-calibration transmitters by simple comparison as part of our design. you can use different transmitter manufactures as diverse devices by doing this you will minimize the common cause but you introduce complicity in the design and additional spare parts need to be maintained ad additional indirect cost.

RE: Level switch as part 2oo3 voting

First and foremost, yes you can use a limit switch in a voting scheme.
On the other hand, assuming that this is for a Safety Instrumented System (SIS), limits switches have a higher failure rate when compared with process transmitters.

With that in mind, perform the SIL calculation and determine if you met the SIL level required.

Red Flag This Post

Please let us know here why this post is inappropriate. Reasons such as off-topic, duplicates, flames, illegal, vulgar, or students posting their homework.

Red Flag Submitted

Thank you for helping keep Eng-Tips Forums free from inappropriate posts.
The Eng-Tips staff will check this out and take appropriate action.

Reply To This Thread

Posting in the Eng-Tips forums is a member-only feature.

Click Here to join Eng-Tips and talk with other members! Already a Member? Login


Resources

Low-Volume Rapid Injection Molding With 3D Printed Molds
Learn methods and guidelines for using stereolithography (SLA) 3D printed molds in the injection molding process to lower costs and lead time. Discover how this hybrid manufacturing process enables on-demand mold fabrication to quickly produce small batches of thermoplastic parts. Download Now
Design for Additive Manufacturing (DfAM)
Examine how the principles of DfAM upend many of the long-standing rules around manufacturability - allowing engineers and designers to place a part’s function at the center of their design considerations. Download Now
Taking Control of Engineering Documents
This ebook covers tips for creating and managing workflows, security best practices and protection of intellectual property, Cloud vs. on-premise software solutions, CAD file management, compliance, and more. Download Now

Close Box

Join Eng-Tips® Today!

Join your peers on the Internet's largest technical engineering professional community.
It's easy to join and it's free.

Here's Why Members Love Eng-Tips Forums:

Register now while it's still free!

Already a member? Close this window and log in.

Join Us             Close