FA125 Data Format June 23, 2015

From GlueXWiki
Jump to: navigation, search

Location and Time

Room: CC F326

Time: 2pm.

Remote Connection

You can connect using BlueJeans using the meeting number 589 693 655 .       (Click "Expand" to the right for more details -->):

(if problems, call phone in conference room: 757-269-6460 might not be the correct number)

  1. To join via Polycom room system go to the IP Address: 199.48.152.152 (bjn.vc) and enter the meeting ID: 589693655.
  2. To join via a Web Browser, go to the page [1] https://bluejeans.com/589693655.
  3. To join via phone, use one of the following numbers and the Conference ID: 589693655
    • US or Canada: +1 408 740 7256 or
    • US or Canada: +1 888 240 2560

More information on connecting to bluejeans is here

Specific instructions for connecting via polycom:

  • Turn polycom on if necessary
  • With the polycom, place a call at 199.48.152.152
  • Press # to enable the polycom keypad, then enter the meeting id: 589693655 and #
  • You may have to unmute the microphone: #*4
  • Turn the computer on if needed

Agenda

  • Previous meeting (June 9, 2015)
  • Status of FADC125 Firmware (report from Cody last week is in the minutes)
  • Version 5.06, 23 June 2015
  • Need to add NPK for number of peaks
  • Need to eliminate unnecessary data modes
  • Parameter PG to describe gap between pedestal sample and threshold crossing (replaces XTHR in user interface)
CDC sample data from many pulses with threshold crossing sample moved to bin 9
hit threshold 120, several peak amplitudes
all peak amplitudes, several hit thresholds
  • Pedestal samples

Useful Links

Minutes

Present: Naomi, Mike (CMU), Beni, Simon, Lubomir (JLab)

  1. Update from Cody last week - he synthesized the CDC combined mode and got some real (eventless) data through his test card using it - headers, trigger time and trailer (he suppressed the event data just to make testing easier in these early stages). This shows that both the new daisy chain and backend architectures work. It looks like he will have to make separate CDC and FDC versions to get the firmware to fit onto the card. When he gets back he'll talk to Bryan about the driver.
  2. We need to add a parameter NPK (number of peaks per trigger) to the firmware/driver spec. Multiple-peak-per-trigger reporting is already in the firmware, but undocumented. At present the max value for NPK is 512 but to prevent data deluge due to accidental typos we would like to limit this to a smaller number, we picked 8. The firmware would only record the peaks found in the window. After the first threshold crossing, the peak search requires a maximum after a minimum; falling below threshold is not required. Each maxima is identified as the sample before 2 consecutive decreasing samples.
  3. We should make sure that in the combined data formats, the firmware is reporting the calculated quantities for each peak but including the raw samples only once. The max window size is 1024.
  4. The format spec mentions output of samples in the 'pulse window' for the combined format. This should be the entire trigger window.
  5. We do not need the raw sample data formats (window or pulse raw data) as the raw samples are included in the combined formats.
  6. We do not need the scaler data format.
  7. We are happy to use the parameter PG to describe gap between pedestal sample and threshold crossing (which replaces XTHR in user interface) and can use plots similar to those above to pick the best value for a given threshold by looking to see where the signals before the pulse diverge, eg for threshold 125, a good value for PG would be 5. Cdc samples3.png
  8. Pedestal samples - Beni found no significant difference between using integer mean pedestal and floating point mean pedestal for subtraction from the integral. He found some strange effects using different batches of pre-pulse pedestal samples, the mean was lowest at the start of the data window. CDC_Pedestal_Studies
  9. Lubomir pointed out that if we integrate from the start of the pulse to a fixed number of samples after the threshold crossing, we don't know how many samples we integrated because the threshold crossing is not output. We will have to fix this. [eg by integrating for a fixed number of samples after the start of the pulse, not the threshold crossing]
  10. The data modes are not listed in the spec and probably should be.
  11. Naomi will compile a list of suggested maximum values for the config parameters and email them to the group. We need to specify maximum values so that the field widths can be allocated in the firmware and driver.

Proposed field range for configuration parameters

These are not intended to be restrictive, but to determine how many bits are needed to pass the parameter values from the software library driver into the firmware.


Name Max value Comments
NW 1024 I think this is the current maximum
P1 7 Initial ped window length NP=2**P1 which would be 128 for P1=7
P2 7 Local ped window length NP2=2**P2 which would be 128 for P2=7
IE 1023 for the CDC we need IE > NW-NP
NPK 15 Lubomir is ok with max of 8; 15 uses the same # bits; can limit this to 8 in software
H 511 Hit threshold
TH 511 High timing threshold
TL 63 Low timing threshold
IBIT 7 Scaling factor for integral is 2**IBIT (using 4 for CDC & 7 uses same # bits)
ABIT 3 Scaling factor for amplitude is 2**ABIT
PBIT 3 Scaling factor for pedestal is 2**PBIT
Retrieved from "https://halldweb1.jlab.org/wiki/index.php?title=FA125_Data_Format_June_23,_2015&oldid=80589"