03-28-2020 08:33 AM
Hello,
I'm developing a Custom Device to read 10 waveforms channels produced by another my Custom Device in order to analyze them and calculate some parameters like RMS.
I read in this list (http://zone.ni.com/reference/en-XX/help/372846M-01/veristand/system_channels_table/) that there is a System Channel called "WPL Overflow Count" with this description "The number of times the Waveform Processing Loop attempts to write to a waveform read session within the NI VeriStand Engine and times out".
I'm monitoring this channel and I saw that when I add the third waveform (reading session) to my Custom Device, it starts to increase.
I don't undertand very weel the description of this channel. I need some more explanations. My doubts is: when the value of this channel starts to increase, I'm losing data?
Somebody can help me,
thank you,
Francesco
Solved! Go to Solution.
04-10-2020 07:56 AM
Hi Francesco,
as per what described here (Avoid Data Loss When Reading and Writing Data), the WPL Overflow Count signals an overflow in a Waveform Read Session, meaning that the Waveform Processing Loop (Producer) has produced more data that the consumers can handle, meaning that the CPU in uncapable to read all the data the CD produces (so yes, it means you have data loss).
Possible solutions, as the guide suggests, would be to change the size of the queue (from the Communication Properties input cluster of Open Waveform Session VI ) or to change the PCL rate in order for the CPU to keep up with the speed the CD produces data.
Best,
Nicola