VME transactions fail - any advice available?

[lippj]

I have a VME-MXI-2 card occupying slot 0 in a VME crate. It talks back to a MXI card mounted in a desktop PC running Labview 7.1 and the Measurement and Automation eXplorer (MAX). This configuration has worked fine until now when it has suddenly stopped working. The only thing that has happened betweeen working and not working is that I've altered the layout of my lab and had to remove the VME-MXI-2 card from the VME crate before replacing it in the new location.

Diagnostics:
I can run the MAX, and then initiate the "Run VXI Resource Manager" command. It seems to run fine and the MXI light on the VME-MXI-2 card flickers two or three times whilst the command runs. No other indicators light up at all, but data hits the VME bus according to my bus monitor.

If I then run my Labview application, which simply moves out a value I get the following report (translated through VISA status description block)
"Bus error occurred during transfer."

And the following error reported when I do VISA close block:
"Status: X Code:-1073807304
Error -1073807304 occurred at VISA Move Out 16 in loop.vi

Possible reason(s):

VISA:  (Hex 0xBFFF0038) Bus error occurred during transfer."

No data appears on my VME bus monitor card, so it appears that nothing is getting through to the VME bus except when the MAX "VXI resource manager" is run.

I'd be grateful for any advice which can be offered in resloving this problem - as I've moved/unplugged and replugged the card, I slightly suspect a harwdware fault, but don't know if the above errors/LED combinatiobns are chracteristic of this - nor do I have any experience of using any lower level diagnostic tools on the system (do any exist?).

Thanks,
John

[Stuart_R]

Hi John,

I'm personally not that familiar with the hardware that you are using but would like to try and help if I can.

Are you saying that everything works fine via MAX and the only issues arise when trying to run code that previously worked fine before you reconfigured your lab? If so then the root of the problem likely lies with the LabVIEW code and I would recommend checking through it for any configuration mistakes such as the way you are addressing the device.

Out of interest, which order do you start your equipment? Do you boot the VME first and then the PC or vice versa?

[tuba]

Hi John,

You mentioned that this problem began when you moved your equipment.  Have you checked the MXI-2 connectors for bent pins?  MXI-2 connectors are rather fragile and easy to bend out of shape if care is not taken when plugging and unplugging them.

If this is not the problem, do you have another PCI-MXI-2, VME-MXI-2, and cables that you can use to try to narrow down the source of the problem?  If you begin swapping components, take care that all the pins are in good shape before plugging anything in.

-tuba

[lippj]

Hi SR,

thanks for being so willing to help - I am a bit more suspicious that I may have developed a hardware fault in my lab move. Nothing has changed on the software side of things so I suspect that it is still OK. Really, nothing ought to have changed on the hardware side too - it was just a case of disconnecting the MXI2 cable whilst I shifted the VME crate.

As for boot order, I generally have the PC running first, but ocassionally the PC will be rebooted (though this does not happen often) after the VME system is up and running.

Regards,
John

[lippj]

Hi tuba,

I have now checked all the pins on the cable and tey seem OK. I am a bit more suspicious that maybe I've managed to damage a chip on the VME-MXI-2 card. If you know of any registers that I can probe to check its correct funtioning, that would be most helpful.

I think I need to start by probing registers 'near' the MXI-2 cable, then look at some at the VME interface, then try accessing register across the VME backplane.

I'm afraid that I do not have any further sets of hardware to try swopping in - this would be ideal as it would let me isolate the problem quickly, but not an option!

Regards,
John

[Stuart_R]

Hmmm, not sure what has happened there then. The only thing I would suggest is checking for bent pins as the other poster mention, as well as trying to change the boot order so that the VME is started first and then the PC, just to see if this has any effect.

Let us know how you get on with this.