RS232 PCI Shielding Problem

[alini]

Hi

I have bought PCI-8430 RS232. I have found that the shield of the PCI card is connected to the GND of the serial ports. In fact a simple continuity test with a multi meter between pin5 of DB9 and the case of the card shows this problem.

When I install the PCI card to the motherboard, the shield of my pc will connect to the GND of the serial devices and this will cause serious problem in my application.

how can I solve this problem?

regard

[crossrulz · Accepted solution]

You should have gotten the PCI-8432, which has isolation between the ports.

[alini]

Thanks for your helpful comment. Is there any other suggestion to save time and money?

[crossrulz]

Give your local NI rep a call.  They may swap out the cards for you (you will have to at least pay the difference in price).

[alini]

Thanks again for the quick reply.

I have read the NI document for PCI-8430 and PCI-8432 once gain.

It seems that PCI-8432 has isolated port to port connection (i.e. the GND pin of serial ports are not connected to each other).

In our application, there is no need to have different GND for each port. It is just enough to have one GND for all ports which is not connected to the earth.

Unfortunately the GND pins of my PCI-8430 serial ports are all connected to the earth. Does this sound okey? Or maybe my card has been damaged somehow?

Best regards.

[even-And]

I recommend contacting RMA and look into exchanging your card for one that better suits your application