Running Data Acquisition program

From MariachiWiki

Programming the board

Data from scintillator detectors can be acquired more easily using the special designed "electronics box" (also known as the coincidence box and the board) connected to a computer. The board is based on a programmable FPGA chip. The chip should be programmed each time it is powered on. The procedure is the following:

• Log in (if not already there) a computer using User account (no password is required)
• Open "Mariachi DAQ" folder on the desktop, then goto "Lab-DAQ" subfolder, run (double-click) "Morph-IC Loader.vi". This window should pop up

• Choose the "Device" "Morph-IC A XXXXXXXX"
• Click "Program" button, you should see "Status: Programmed OK" (as in the picture)
• Click on "Quit" and close the window
• Don't close LabView window you will need it later...

Now the chip should be loaded. You can verify this by seeing the green led on under the cover near the USB connector. Each time this led is off you need to program the chip again.

More details: The window which shows up is not "quite" a normal Windows program. It is actually a "source code" written in G graphical language in the context of LabView software. When you press "Quit" button the program stops. To start it again one should click on the arrow in the left top corner. The program load to the chip a specially prepared file (Mariachi DAQ\Full-DAQ\altera\mariachi.RBF) which contains the program for this chip.

Running the Data AcQuisition (DAQ) program

The board constantly updates counts of pulses and coincidences coming from the detectors and keeps them in its internal memory. You need a computer again to read them out and turn into something visual and useful. We will use LabView program to do this. The program is run by clicking on DAQv2.vi. Here is its main interface:

• • The program can be run the predefined amount of time which is set in "Auto Stop Time" box. To run it press the right arrow button in the top left corner. It will stop automatically after the set time is passed.
  • "Run Time" shows the actual time the program is running.
  • Two columns in the center show counts from all the connected detectors and different coincidences counts (left column "Singles Count, x10", "Coincidence Count") and the corresponding boxes in the right column show rates of these quantities (counts per second). "x10" means that to get the real value you should multiply the number in the box by 10. This has to do with saving memory resources inside the FPGA chip (the smaller the number is the smaller the amount of memory to keep it in. E.g., in the picture you can see that during the last 100 second about 48080 pulses from the first and about 21140 pulses from the second connected detectors were registered. The number of coincidences was 1828 and the coincidence rate was 18.3Hz (Hertz=times/second).
  • By the end of each run of the program measurement data are automatically recorded to a next column of a table (see the picture) and the table is automatically saved in the file pointed in "Save data to file" box. The file can be imported to a spreadsheet program for further analysis.