Frequent occurrence of Watchdog Timeout

[Nottingham_SDG]

Hi. I'm using a 7344 card to get one axis to follow a prescribed (relative-contouring) profile and acquiring inputs from four ADCs as regularly as I can. Watchdog timeout errors have started occurring regularly and I do not know why. Any hints ?

An onboard programme grabs encoder position plus four ADC values each time through a loop and puts them in buffer. A host programme empties the buffer every 50 cycles (flagged by bit 13 of MCS register). The host programme tops-up the position buffer each time it empties the data buffer. It seems to work perfectly "often" but throws up a timeout error from time to time.

[SheelaS]

Hi,

Just to get a better insight into why this is occurring, can you copy the error message here?

Thanks

[Nottingham_SDG]

Hi.  I have now made it go away by getting the host computer programme to wait 2ms before polling the card again. I think perhaps that the card was overpowered by incessant requests to return the MCS register.

I do not recall the exact error message but it contained "watchdog timeout error" and the instruction to power-cycle the host computer and to contact National Instruments if the problem persisted. My early theory was that it might have been a thermal thing but it has gone away now anyway. Thanks

[SheelaS]

Nottingham_SDG,

Glad to hear you got things working.  Your solution imlpies you had no timing in your while loop, and therefore causing the loop to run as fast as the processosr would allow.  We recommend that you always put in some timing into a loop to allow your processor time to execute other applications/services.

All the best with your application,