Known issues of NI USB232/4

[navkuma]

Hi,

I am planning to use usb-232-4 NI hardware in our project.
my use-case is to read rs232 serial port channels every 500ms once. our system is configured to run for long period (3~4 months)

So once I create a VISA session with Hardware port, it is used until I stop the application (~ after 4 months)

So I would like to understand is there any issues/difficulties could occur with NI USB 232/4  for my use case?. Please share yours experience/thoughts with this hardware.

Specifically connection lost issues and VISA Hang issues.

[crossrulz]

I have not used that specific device, but here are a couple of general comments based on the requirement you seem to be most worried about.

I would avoid USB.  I would much rather go with a PXI or PCIe card to handle the RS-232.  They are a lot more stable and reliable than USB.

If you still insist on using USB, make sure you have a commercial grade, externally powered USB hub that your devices are plugged into.  USB hubs on PC motherboards tend to not be able to handle the current draw.  Having a good, powered hub helps alleviate this.  I am personally a fan of StarTech.

[santo_13]

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@navkuma wrote:

Hi,

I am planning to use usb-232-4 NI hardware in our project.
my use-case is to read rs232 serial port channels every 500ms once. our system is configured to run for long period (3~4 months)

So once I create a VISA session with Hardware port, it is used until I stop the application (~ after 4 months)

So I would like to understand is there any issues/difficulties could occur with NI USB 232/4  for my use case?. Please share yours experience/thoughts with this hardware.

Specifically connection lost issues and VISA Hang issues.

---

I assume your computer HW and SW is stable for a 24x7 run for 4 months, windows is known for its weird update schedules and BSODs.

[JÞB]

A few other things;

Use the Ferrite on the high quality USB cable supplied with the device and physically lock the system to prevent unauthorized access    some "friend" in your lab is going to feel like they need that easy to grab cable more than you need it.

Make sure that the Windows Power Management settings for the USB Hub are set to Never allow the OS to shut down the port to conserve power.  Trust me, I've seen guys struggling over that