Random 200141 and 200019 error messages -

Question

Hi,
I have a new problem with an old code which is a random failing mid-run stating error 200141 or 200019. The code (in LabView 8.2) calculates engine speed from the pulses of an encoder, and takes pressure readings at each encoder point, with PCI-6143 board and SCB-68 connector block. A few weeks ago this would run fine for 10 minutes plus but has recently started coming up with these error codes mid run more and more frequently. The error messages seem to be related to too samples being processed with not enough time to do so - but does not occur with any relation to the frequency of acquisitions (engine speed), but to occur randomly. I have watched the CPU in task manager as the program runs, but it only uses about 2% of CPU (except for the start which uses about 10%).
Because of the random nature of these errors, and the fact that this program used to work ok (at even higher acquisition rates), I can only think that there must be something wrong with the operating system which is limiting the access of the program to CPU - perhaps a virus that my antivirus software has not picked up. I have already tried re-installing LabView and DAQmax, but to no avail. Does anyone have any ideas as to what else may be causing this - a fault with the encoder perhaps? Or how I would be able to check this? - I am a bit unenthusiastic about wiping and re-installing the whole operating system, especially if it may not help, but I cannot think of any other options at the moment.
Any help or suggestions would be most appreciated.
Thanks

Answer 1

Hi Henry,
Error -200019 is a hardware error that occurs if two clock edges occur too quickly.  For example, the 6143 has a maximum clock rate of 250 kHz.  As you increase the sample clock rate higher than 250 kHz, you would eventually see this error message.
Assuming your external clock rate is indeed under 250 kHz, the most likely cause of this error would be noise on your input line causing multiple clock edges to be picked up by the board in quick succession during a single transition.  The likely remedy would be to use an external Schmitt Trigger.  I should also point out that later generations of DAQ hardware have digital filtering available on the PFI lines that could also be used to solve the problem--unfortunately the feature is not present on the 6143.
Error -200141 is also a hardware error, indicating that the data is overwritten on the board before it can be transferred to your computer.
What is the rate that you are trying to sample your counter?  It's possible that noise on the clock line could cause this problem as well, especially if the behavior seems to occur randomly.  The other possibility is that your external sample clock is too fast, and a slight delay in the data transfer could cause the value that was previously sampled to be overwritten.  This is a fairly common error for high rate counter measurements on
hardware released before on-board FIFOs were added for counters.  For example, X
Series and 2nd Generation cDAQ both have on-board counter FIFOs.
To summarize, it sounds like you probably need external conditioning to prevent duplicate edges from being detected by the DAQ board.
Best Regards,
John Passiak