Error -50400 occurred at Invoke Method: FIFO.Read in Host.vi

Question

Hey there,
we have sensors on an Engine which are connected to a NI cRIO 9014 board (with a NI9411 6-channel digital input modul) and go from there via network to a host computer.
cRIO board: the cRIO board collects the data from the engine and stores it in a buffer, this is because the network is to slow for the magnitude of data
host computer: the host computer reads over the network the buffer on the cRIO board, on the host computer it takes out specific portions of the data to create pressure graphs of the engine
Error: 
Error -50400 occurred at Invoke Method: FIFO.Read in Host.vi
Possible reason(s):
The transfer did not complete within the timeout period or within the specified number of retries.
This error occurs in the following scenario:
- engine is running
- cRIO is running
When I press the start button (boolean 3) in the host.VI to start the reading of the data from the board AFTER I pressed the run button of the host VI. 
The Error would not occur if I pressed the start button (boolean 3) BEFORE I pressed the run button of the host VI.
We tried to increase the time out, but it still did not work, the error occurs!
We would be really happy if you could look over it and help us in this case! If you need further informations or if we need to clarify some specific portion, please let us know!
We included the VI's in the attachement!
Thanks in advance!
Solved!
Go to Solution.
Attachments:
Host.vi ‏152 KB
C_RIO.vi ‏92 KB
Cyl_Pres.lvproj ‏196 KB

Answer 1

Chrisse,
There are a few things wrong in your application, if I may offer some suggestions.
First, your while loops are not running in parallel.  In fact, they are in while loops with a true constant wired to them. I am not sure if this is by design for debugging, or on accident.  I would put the Polling(read pulling zero elements) outside your main while loop.
Your second nested while loop (the one polling the # of elements and then pulling them out) is going to run just once, and may pull only a few samples.  I don't think that is what you are looking for here, and there are a couple ways we can go here.  You could continuously poll until you have 0 elements available for x amount of time, then you know you have no more samples available and you can process all the data OR you can put all of your data processing as part of that loop and just always write to file immediately as x samples are pulled.
Also, your main loop's stop condition is (i <= 3) Therefore, it will run once and then stop.  Maybe you mean >=3?
Also, you have 'append to file' disabled on your write to spreadsheet, so everytime you write you are overwriting old data.  If you want to continuously write, you will be losing data.  This can be cured by either setting this to true(requiring a new file name or programatically deleting the old spreadsheet every time you run the vi) OR you can collect all of your data in a shift register, and only write to file once you have all your data available.
The error you are seeing is because you try to close your FPGA reference twice.  You only need to close it once.
After seeing your overall picture, I think this can all be cured by simply hardwiring your Read to get your 1440X4 elements, but as we have seen, this does not work.  Something is happening in your system....this is what I want you to do...run just the following code...and let me know how many elements remaining it gives you...Once the number has settled(I hope it does and your engine doesn't keep running), hit stop, and all the values will be put on a graph for you.  My broken wires are because I do not have the FPGA VI.
Message Edited by Robbob on 04-21-2009 01:48 PM
Rob K
Measurements Mechanical Engineer (C-Series, USB X-Series)
National Instruments
CompactRIO Developers Guide
CompactRIO Out of the Box Video
Attachments:
numelements.jpg ‏39 KB