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!
  • Students Click Here

*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


Interpreting vibration spec

Interpreting vibration spec

Interpreting vibration spec

Hi All

I have an environmental specification for a PLC which I'm struggling to interpret.

Functional Stress
5Hz to 9Hz
1.7mm amplitude
3.5mm amplitude
10Hz to 150Hz
10Hz to 150Hz

What are the definitions of Functional Stress, Withstand and Endurance?
Any help appreciated.


RE: Interpreting vibration spec

I'd contact the manufacturer, because otherwise you are guessing.

But if I were guessing (who can resist?),

"functional" levels are the vibration frequencies and amplitudes under which the unit is verified to remain functional, i.e. control of your process is continued un-interrupted. Likely, the 5-9 Hz range is where the relay outputs are resonant, and amplitudes somewhere above those listed may cause intermittent, unintentional, open/close of the relay contacts.

"withstand" - unit is rated to withstand these levels, though function is not guaranteed, without sustaining permanent damage. Most likely set by a combination of testing and stress/fatigue analysis.

"endurance" - likely a level of acceleration verified by testing over some fixed duration, below these levels no failures were observed.

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!


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