I am using a VI very much like the one attached here, and as my motor speeds up and the period value decreases, the vi fails, and error 200279 shows up as displayed in the attached 2 jpg images. This VI is reading the period value of an encoder by rising edges. The error does not show up at low speeds, only high speeds. Hardware is wired through USB ports on PC. Using Labview 2012 and Windows 7.
Do I need to specify the samples per channel for the READ in the case structure to eliminate this error? The error only occurs when the period gets quite short, e.g. 9ms or so. At higher period values (slower motor speeds) the error does not appear. I am using the counters built into the cDAQ9174 chassis and the NI 9401 module to read the period values of my encoder. What is happening at high speeds to cause this error? I thought that the setting on the DAQ Timing VI required that 16 periods are read every iteration, so, why is it saying that it is trying to read samples that are no longer available?
Also, is the "Append Array" building up a large array that is being carried in the SHIFT REGISTER and causing things to slow down? There are a huge number of periods occuring with an encoder at 120 ticks/revolution. should I try to keep this array truncated or something to reduce the size of the data being handled for each iteration? Can this large array be causing the 200279 error?
Thanks,
Dave