how many tasks can be ran at same time

[morris44]

Using VI logger lite and I have ran 2 tasks at the same time using 9162 via 9211 and 9162 via 9215a at 1 Hz for hours and had no problems.

Also did not use the external power for my usb hub. Used laptop with xp. sample rate of 1 Hz for 8 channels

Now I am trying to run 4 tasks at the same time using 2 of the 9211 and 2 of the 9215a. I am now using external power on usb hub. Now I am getting errors in VI logger  saying it's lost module connection after 15 minutes of recording data from 4 tasks. Also am getting blue screen errors on laptop(DOS screen error messages about this error (driver error)). What is up with this? no one on phone support can answer my questions please help. Do I need a new laptop or new usb hub or have I maxed out VI. sampling 16 channels at 1 Hz so it's not high speed issue.

[David L.]

Hi Morris,

Thank you for contacting National Instruments support. I appologize that you were not happy with our phone support, but would like to ask for your previous service request number. I am interested in the notes from the SR so that I can get a better idea of the history behind this issue and what has already been done to research it.

Although your hub is connected to an external power supply, have you double checked that it meets specifications to power two 9211's and two 9215a's? What hub do you have? Does this error occur if you only have 3 USB modules connected to the hub? Does this occur if the hub is connected to a desktop? Any more information about the blue screen could also be helpful.

[morris44]

NI ref#7145290

I'm using win xp dell latitude laptop with 256 RAM. USB driver is 1.1

If I remember right the BIOS error had something to do with a generic driver update message probably for the usb driver to be upgraded to 2.0 but I was getting VI logger lite error messages first.

I have not tried this on a desktop yet. I bought a USB 6210(getting it tomorrow probably) so I will be using 3 nodes instead of 4. USB hub is a Belkin 4 node hub with external power. I asked NI what is the recommended usb hub but they said any off the shelf hub will do.

I have been doing 3 nodes with 2 9215A's and one 9211, so far there has been no issues yet with my testing ( 3 hour record time) will do more testing today.  I wouldn't say that I was unhappy with phone support just was wondering why this hasn't been defined in a spec sheet.

I realize that there is hardware involved that is not under NI product line like laptop, RAM and USB driver version etc...

Does it matter what USB driver update I should use to go to usb 2.0? If not where can I get one for this laptop? Dell website wasn't forthcoming on this. I just don't want to compund this issue with a usb driver that has conflicts with this laptop.

Is there minimum RAM requirements also?

Any other recommendations will be welcome. Thanks for responding.

[David L.]

Morris44,

I tried this on my computer with simulated devices, and successfully ran four tasks in VI Logger simultaneously . It is interesting that you say that having 3 devices connected does not cause a problem. Please let me know if you have any results of testing with a desktop, along with the results from testing with the 6210.