isolation network module

[Yan Sim]

I have a FP-1000 network module with a FP-AI-100, FP-DI-300 and FP-DO-403. I am using RS-232 serial communication. I have fried both of my computer's serial ports. Nothing happen to the network module or I/O modules. Can any one tell me what happen? How do I prevent this? I think I need an isolation serial board. Can anybody confirm that?

Yan

[e-Cash-Money]

Hello Yan,

I am not sure how your computer's serial ports got fried, I've actually never run into this before. The only thing I can think of is either a defective (or out of spec) power supply for the computer or a defective (or out of spec) power supply for the fieldpoint controller. If you had a serial isolation board, it's possible that it would help, but I'm somewhat doubtful. The isolation boards provide isolation from port to port. So you could still fry those ports depending on what is currently frying your ports. Perhaps you could give us some more information about your system set up, the conditions surrounding the frying of the computer's com ports, and any other information or troubleshooting you have done that may be relevant.

Thanks,
E.Lee

[Yan Sim]

I am using the FP-1000 with Labview to automate a test sequence on a cable sample. The problem happened rather randomly. The problem being frying a serial port. The field point may be doing fine for a few days or a few months.
When the problem happened, I see an error message " cannot find remote devices" the same time as the cable sample failed. So it almost seems like there is a voltage surge when the cable sample failed.

[e-Cash-Money]

Hello Yan,

If the FP-1000 is frying your computer's serial ports, you might have a defective controller. In any case, I would highly recommend that you give NI a call to continue troubleshooting and find out if you have a defective controller.

Here is the website, just choose the option to "Phone NI"
http://sine.ni.com/apps/we/niae_asc.main

Take care,
E.Lee

[Aaron_G]

Yaan,

RS-232 is a single-ended communication method. This means that the FieldPoint module and your computer will share a common ground through the RS-232 cable. If the ground level for either the FieldPoint module or your computer is at a different level, you can either lose communication (for small differentials) or cause damage to either the computer or FieldPoint device. Proper ground techniques and/or using an isolated serial board in your computer can minimize these risks.

Regards,
Aaron