I have a machine that gets pulses from a FPGA to servodrive when i operate it.
But every now and then the FPGA loosens from it’s socket (the card and chip is pretty new) , and when the machine vibrates it seems like the FPGA gives pulses to servodrive and the motor goes by itself.
I can press it down in the socket and the problem dissapears for a while. and comes back.
What can i do?
The chip is an Actel A42MX16-PLG84
Hello,
The only thing I can think of is replacing the socket. Maybe you got a bad one.
Welcome to the forum.
The problem of heavy machinery vibrations loosening ICs in sockets is why so many industrial PCBs do not use any sockets, all IC’s are soldered to the PCB for orders of magnitude more vibration resistance.
If the socket is absolutely necessary, then vibration dampening can be added to the PCBs enclosure to lessen the problem.
Not knowing what kind of room consideration you have for your enclosure/device, vibration dampening would usually be thought out during the design rather than applied after.
We sell this kind of thing that might help with that kind of vibration.
Sometimes a fix includes using large rubber o-rings to suspend a device from the corners:
Hi ebratteberg,
Wow, that is a really old device architecture! I haven’t seen 5V in an FPGA in quite some time. It looks like it first appeared around 1997. I see that your part is on a “Last Time Buy” status now. If you need any more of them, I would recommend getting them fairly soon.
@Kristof_2649’s suggestions for damping materials to help isolate the board from the vibration source might be worth looking into. Below are links to some additional damping products from companies which specialize in shock absorption/damping products:
If that’s not a viable option or if it proves to be insufficient, then the other options I can think of would be to devise a mechanical clamping structure to help retain the part, or, as a last resort, use adhesive underneath the FPGA to affix it to the socket. Of course that would make removal and replacement nearly impossible, but it might buy you some time.
Thank you for all the good answers.
I really dont know how to get the FPGA out of it’s socket, would be nice to take a look at the socket and see if any of the pins are bent or something.
It’s scary to have a machine that wanders by itself (servodrive getting signals from FPGA).
It helps to have an extraction tool to be able to pull up the PLCC from two corners. The below one is a universal sized tool
