Increasing number of error codes in Run Time


We have been starting to see an increasing number of error codes while running procedures. The errors that we get are; E2756: IEEE-488: (NI) Unknown error, E2740: IEEE-488 (NI EDVR) DOS error and the last one I missed to write the number down but the error message said IEEE-488: (NI MAX) DOS error.

I am guessing they all have something to do with the NI drivers for our NI GPIB-USB-B interface but since the errors have occurred after an update to the latest drivers I am uncertain if the fault lies with MET/CAL, the drivers or the hardware.

Anyone here who got any thoughts on the matter?



Joakim Spångberg


Date Votes
Krista E.

A couple of things:

1) EDVR is almost always a board config error.  Make sure you tell Met/Cal exactly the number of boards you have in your system (what NI can see).  This can also (rarely) be caused by upgrading from win XP to win 7 without upgrading your NI drivers.  The NI drivers are free from NI and you should always make sure you are up to date for your OS.

2) Random timeouts can be caused by bus timeout being set to too fast a speed (setting 2 which is 500nsec is too fast for most instruments) and you just need to change it to the lowest setting (1 or 2usec) to fix a lot of those issues.  

3) You can turn on I/O trace for GPIB from the debug menu.  All metcal does is echo the lowest level error coming back from NI.  So if you turn on I/O trace you usually get a more descriptive error message.

Hope this helps.


John Evans

We use to use NI GPIB-USB-B interfaces with no problems for quite awhile, then we started to get problems you described. Eventually, we were able to narrow down problem with the interface. There is a known problem with the USB-B interface with a capacitor on PCB. This would cause loss of communication with interface. It would be instantaneous, but enough to cause METCAL to go off the rails. We sent in our USB-B for repair, but I don't think NI stills does this. Besides, the problem eventually came back. So we replaced USB-B with newer USB-HS and problem has never happened again.

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