Interpreting vibration spec
Interpreting vibration spec
(OP)
Hi All
I have an environmental specification for a PLC which I'm struggling to interpret.
Vibration
Functional Stress
What are the definitions of Functional Stress, Withstand and Endurance?
Any help appreciated.
Cheers
elbrownos
I have an environmental specification for a PLC which I'm struggling to interpret.
Vibration
Functional Stress
5Hz to 9Hz
Continuous1.7mm amplitude
Occasional3.5mm amplitude
Withstand10Hz to 150Hz
Acceleration0.1g
Endurance10Hz to 150Hz
Acceleration0.5g
What are the definitions of Functional Stress, Withstand and Endurance?
Any help appreciated.
Cheers
elbrownos





RE: Interpreting vibration spec
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.