PXI-2501 relay life

[ltok]

Hi,

I would like to know the relay life of PXI-2501.

For PXI-2503 and others, I can find the relay life (electrical and mechanical) in its specification manual, under Dynamic Characteristics. However, I cannot find the relay life for PXI-2501 under its specification manual, under Dynamic Characteristics. Could anyone tell me the relay life of PXI-2501 (for both electrical and mechanical)??

Thank you & Regards

Lee

same post as http://forums.ni.com/ni/board/message?board.id=170&message.id=279408

[Hani R]

Hi Lee,

The NI PXI 2501 is a Field-Effect Transistor (FET) switch, whereas the NI PXI 2503 is a mechanical relay switch.  The advantage of a mechanical relay is that it is more robust than an FET switch.  Because of its mechanical nature, the PXI 2503 will begin to degrade after millions of operations due to wear and tear.  The PXI 2501, however,  is going to be much faster and have an unlimited transistor lifespan.  You should select your switch based on the speeds you need to achieve, the topology that suits your application, and your voltage range.  I hope this helps. 

[chericks1]

Hi Lee,

I apologize if this issue has caused you any confusion.  Hani is correct in his reply.  The FET's lifetime has no correlation with the number of times the relay is cycled.  The relay (and its control circuitry) involves no physical moving parts, so mechanical lifetime really does not apply.  In reference to electrical lifetime, as long as the signals are within the relay's specifications they will have no adverse effect on the FET.  Therefore, in reference to number of cycles, the lifetime of a FET relay is unlimited. 

To be fair, all components will fail over time due to age and other external environmental factors.  However, because these failure modes are somewhat variable and difficult to predict, such a specification would not be suitably relevant nor repeatable from module to module.

I hope you understand the reasoning behind this inconsistency.  Let us know if you have further questions! 

Best regards,

Chad Erickson
Switch Product Support Engineer
NI - USA