labview error while data acquisition

[aviaashu]

Hello there,

I am using labview to image acquisition in a microscopy experiment. While using the program for capturing the images of higher resolution , i mean more data points, I am getting a error. I am attaching a screenshot of the error massages , that pops up. Basically the massage says "some or all the samples requested has not yet acquired". To wait for samples to become available use a longer read timeout or read later in your program.

What does this actually means?

Thank you

[PalanivelThiruvenkadam]

Check this out, This may give you a hint

https://forums.ni.com/t5/LabVIEW/Error-200284-with-DAQmx/m-p/2683377

[Bob_Schor]

You've not told us about your hardware, you've not told us about your camera's Frame Rate, you've not told us if your images are Color or 8-bit Greyscale, you've not told us how your camera is connected to your PC (USB-2, USB-3, TCP/IP), you've not told us the Resolution you can and cannot use, and you haven't provided any code.  So we can only "guess", based on the Error Message you received.

An Image is composed of Pixels, represented as bytes of data.  To acquire an Image, data has to be transferred from the Camera to the PC over some transport path, such as USB or Ethernet.  How much data depends on Frame Rate, Resolution, and Image Type (none of which we know).  

Your Error Message suggests that you are trying to process Image Data before the Data have been acquired.  This may be simply bad LabVIEW coding, or it may be a more complex issue involving trying to stuff too much data into too little processing time.  Almost impossible to tell without the following:

• The VI (not a Picture, but files ending in .vi, or better yet, the entire Project Folder compressed into a .ZIP file).
• The parameters of Image Acquisition -- transmission path (USB 2, USB 3, Ethernet), frame rate, Image type (RGB, 8-bit Grey).
• A brief description of what you are doing with the Images (just displaying them, saving them to disk, doing "Real-Time" Image Processing, etc.).

Bob Schor

[aviaashu]

Hello Mr.  Schor. Apologies for the sloppy job in previous post. The details are as follows.

1. I am using a 6353 X-series (PCIe).

2. The detector is a Hamamatsu Photomultiplier tube with current output. the output from the PMt is terminated in a transimpedance amplifier to convert the signal in redable voltage and then it is connected to NI breakout box. (all connections BNC)

3. The sample is positioned on a piezostage (Mad city lab nanolp 200) which is driven by  0-10V provided by the NI board through the output channels of same breakout box mentioned in previous point. The stage has xyz movement capability and separate BNC channels for providing the drive voltage. Currently we are engaging just the x and y as we are doing two dimensional imaging. The stage specifications say that it can traverse as low as 4 angstroms , so I think on resolution parameters, our settings are fine as the minimum we intend to go is 50 nm.

4. I am attaching the program and the sub VIs in a compressed folder.

5. The program appeared as a publication for this sort of experiment. I am attaching the pdf as well

I will describe , how I am trying it out.

1. As shown in the figure attached in the original post, we disable the counter, as our detector is not photon counter, its an analog device.

2. The input channel ai0 is engaged for registering the voltage from transimpedance amplifier.

3. The output channels ao0 and ao1 are engaged for providing voltage to the stage for movement . ao0 for x-axis , ao1 for y-axis. 

4. I usually keep my pixel dwell time  in milliseconds, but it ranges from microseconds to seconds , depends on signal strength and on your samples integrity under the laser irradiation.

5. Low time (or silent time during which the stage moves from one point to the next during the raster scanning), so far I have kept in millisecond. This decision was driven by the stage settling time data taken from its specification sheet which is in millisecond range for x,y and z axis albeit a little bit higher for z axis compared to the x and the y axis.

6. xmax and ymax decide the length in micrometers that you assign the stage to move along x and y direction respectively. 

7. Resolution is goverened by Nb points x and y. Suppose for xmax 100 micrometers and Nb point 100, the step size will be 10/100  i.e 0.1 micrometer.

8. We usually keep all the x, y parameters same to maintain an square aspect ratio.

9. After one round of acquisition is over, the Image ctr window refreshes. However, we have noticed that acquisition do not stops after that and  the window keeps on refreshing after each set of acquisition. So, we have to manually terminate the acquisition.

9. We export the data in excel format which is then rendered into an image using matlab.

Thank you for your interest.

I will be happy to provide any other information that is needed.

P.S : We are running this program on LV 2010.

[Bob_Schor]

That is extremely helpful!  You are starting from Published Code (which I assume is "mainly working", though you may have modified it for your own hardware and purposes).  It comes with Documentation (the manuscript in Computer Physics Communication) and you've provided additional information.  I'm going to read the documentation and look at the code you sent -- it may take some time for me to respond, but others will probably also take a look.

Bob Schor