ELOG DRS4 Forum

sub-ms precision timestamps?

Putting sub-ms precision into the header does not make sense, since the USB transfer only happens in time-slots of about 2 ms. To get better timing, you would need a hardware time clock in the FPGA, which does not exist right now.

Best,
Stefan

Will Flanagan wrote:

Dear DRS4 community,

Is there a way to extract timestamps with sub-ms precision? The milliseconds of an event is clearly given when unpacking the header. I would like to determine how far apart events are when they are within the same millisecond.

Thanks,

Will

671

Wed Mar 14 09:13:39 2018

confusion about the description in drs.cpp

Hi,Stefan:

Attachment 1: 20180314161201.jpg

668

Wed Mar 14 00:38:15 2018

Will Flanagan

sub-ms precision timestamps?

Dear DRS4 community,

Thanks,

Will

667

Thu Mar 8 22:54:20 2018

Rodrigo Trindade de Menezes

Running drs_example.cpp

We found a way to solve the previous problem, but right now when we try to set the input range only -0.5 to 0.5 is working. When we set the function "SetInputRange(0.5)" for 0 to 1V the output is all zeros and with "SetInputRange(0.45)" we just get all the outputs -49.9mV. What does that means? How to fix?

odrigo Trindade de Menezes wrote:

Hello,

We have been using the DRS4 evaluation board (S/N 2636) that works with the scope application. However we are trying to run the DRS4 evaluation board remotely by modifying the drs_exam.cpp to acquire and store data continuously.

We compiled the DRS_example.cpp without the wxWidgets but when we try to run the program, it appears to trigger on nonsense. The program appears to not be sensitive to the trigger threshold (although for very large trigger threshold it gets stuck in a waiting mode). Is there a way to ensure that the "normal" trigger mode is set? We are worried that the auto mode is running. Otherwise, not sure why the program is triggering on nonsense. By the way, it does not work with the wxWidgets compiled either so we are worried that there is an additional flag that needs to be set. The routine does not appear to conduct a calibration -- is this not necessary?

Another issue that we are having is with the data set stored on the .txt file looks incorrect. The time channel stops at 200 (but we think it should go up to 1024). In addition, the voltage channel appears to hover around small values near zero (as if triggering on noise). The output file appears this way even when we change the threshold to much higher values. It suggests that the trigger threshold is not actually being set? There are events where the output voltage appears to oscillate through huge negative and positive values too. So not sure what's going on.

Thanks!

Rodrigo

666

Wed Mar 7 22:49:38 2018

Rodrigo Trindade de Menezes

Running drs_example.cpp

Hello,

Thanks!

Rodrigo

Attachment 1: drs_exam.cpp

/********************************************************************\

  Name:         drs_exam.cpp
  Created by:   Stefan Ritt

  Contents:     Simple example application to read out a DRS4
                evaluation board

  $Id: drs_exam.cpp 21308 2014-04-11 14:50:16Z ritt $

\********************************************************************/

#include <math.h>

#ifdef _MSC_VER

#include <windows.h>

#elif defined(OS_LINUX)

#define O_BINARY 0

#include <unistd.h>
#include <ctype.h>
#include <sys/ioctl.h>
#include <errno.h>

#define DIR_SEPARATOR '/'

#endif

#include <stdio.h>
#include <string.h>
#include <stdlib.h>

#include "strlcpy.h"
#include "DRS.h"

/*------------------------------------------------------------------*/

int main()
{
   int i, j, nBoards;
   DRS *drs;
   DRSBoard *b;
   float time_array[8][1024];
   float wave_array[8][1024];
   FILE  *f;

   /* do initial scan */
   drs = new DRS();

   /* show any found board(s) */
   for (i=0 ; i<drs->GetNumberOfBoards() ; i++) {
      b = drs->GetBoard(i);
      printf("Found DRS4 evaluation board, serial #%d, firmware revision %d\n", 
         b->GetBoardSerialNumber(), b->GetFirmwareVersion());
   }

   /* exit if no board found */
   nBoards = drs->GetNumberOfBoards();
   if (nBoards == 0) {
      printf("No DRS4 evaluation board found\n");
      return 0;
   }

   /* continue working with first board only */
   b = drs->GetBoard(0);

   /* initialize board */
   b->Init();

   /* set sampling frequency */
   b->SetFrequency(5, true);

   /* enable transparent mode needed for analog trigger */
   b->SetTranspMode(1);

   /* set input range to -0.5V ... +0.5V */
   b->SetInputRange(0);

   /* use following line to set range to 0..1V */
   //b->SetInputRange(0.5);
   
   /* use following line to turn on the internal 100 MHz clock connected to all channels  */
   b->EnableTcal(1);

   /* use following lines to enable hardware trigger on CH1 at 50 mV positive edge */
   if (b->GetBoardType() >= 8) {        // Evaluaiton Board V4&5
      b->EnableTrigger(1, 0);           // enable hardware trigger
      b->SetTriggerSource(1<<0);        // set CH1 as source
   } else if (b->GetBoardType() == 7) { // Evaluation Board V3
      b->EnableTrigger(0, 1);           // lemo off, analog trigger on
      b->SetTriggerSource(0);           // use CH1 as source
   }
   b->SetTriggerLevel(0.3);            // 0.05 V
   printf("Trigger Level CHNN1: 100mV\n");
   b->SetTriggerPolarity(false);        // positive edge
   
   /* use following lines to set individual trigger elvels */
   //b->SetIndividualTriggerLevel(1, 0.1);
   //b->SetIndividualTriggerLevel(2, 0.2);
   //b->SetIndividualTriggerLevel(3, 0.3);
   //b->SetIndividualTriggerLevel(4, 0.4);
   //b->SetTriggerSource(15);
   
   b->SetTriggerDelayNs(0);             // zero ns trigger delay
   
   /* use following lines to enable the external trigger */
   //if (b->GetBoardType() == 8) {     // Evaluaiton Board V4
   //   b->EnableTrigger(1, 0);           // enable hardware trigger
   //   b->SetTriggerSource(1<<4);        // set external trigger as source
   //} else {                          // Evaluation Board V3
   //   b->EnableTrigger(1, 0);           // lemo on, analog trigger off
   // }

   /* open file to save waveforms */
   f = fopen("data.txt", "w");
   if (f == NULL) {
      perror("ERROR: Cannot open file \"data.txt\"");
      return 1;
   }
   
   /* repeat ten times */
   for (j=0 ; j<1000 ; j++) {

      /* start board (activate domino wave) */
      b->StartDomino();

      /* wait for trigger */
      printf("Waiting for trigger...");
      
      fflush(stdout);
      while (b->IsBusy());

      /* read all waveforms */
      b->TransferWaves(0, 8);

      /* read time (X) array of first channel in ns */
      b->GetTime(0, 0, b->GetTriggerCell(0), time_array[0]);

      /* decode waveform (Y) array of first channel in mV */
      b->GetWave(0, 0, wave_array[0]);

      /* read time (X) array of second channel in ns
       Note: On the evaluation board input #1 is connected to channel 0 and 1 of
       the DRS chip, input #2 is connected to channel 2 and 3 and so on. So to
       get the input #2 we have to read DRS channel #2, not #1. */
      b->GetTime(0, 2, b->GetTriggerCell(0), time_array[1]);

      /* decode waveform (Y) array of second channel in mV */
      b->GetWave(0, 2, wave_array[1]);

      /* Save waveform: X=time_array[i], Yn=wave_array[n][i] */
      fprintf(f, "Event #%d ----------------------\n  t1[ns]  u1[mV]  t2[ns] u2[mV]\n", j);
      for (i=0 ; i<1024 ; i++)
         fprintf(f, "%7.3f %7.1f %7.3f %7.1f\n", time_array[0][i], wave_array[0][i], time_array[1][i], wave_array[1][i]);

      /* print some progress indication */
      printf("\rEvent #%d read successfully\n", j);
   }

   fclose(f);
   
   /* delete DRS object -> close USB connection */
   delete drs;
}

665

Fri Mar 2 21:05:48 2018

ROI

Great! That is very helpful.

One more question. If no signals were detected in the 1024*200ps time frame in ROI mode, would the DRS4 go dead for 32us (or 30us depending on the supply) for, or would it dump the earliest events in the buffer for the more recent ones until it detects a signal to readout? Or rather, does filling the buffer force a readout or can it dynamically shift out old data until it detects a signal to readout.

Steven

Stefan Ritt wrote:

N'/N is correct. The 2 us "from the response you got from me" come from the fact that after readout, you have to start the DRS4 again. During this time, the power supply usually becomes slightly unstable, and it takes on the evaluation board about 2us to stabilize it again. Tha't why I add the 2 us. If you don't care about slight offset effect, or if you make a better power supply, you dead time would be 10*30ns = 300ns for 10 samples. Starting the DRS again will take one or two clock cycles from the FPGA, which might add another 30 ns or so, depending on how you program the FPGA. So the best you can achieve for 10 samples is maybe 330 ns, if you have a really good power supply (large capacitors).

You can achieve this functionality with the evaluation board, but you would have to make a special firmware for it.

Stefan

Steven Block wrote:

Hello,

I have a question about how ROI works. From what I have read, it will only save data that ocurs some time [t_a] dictated by the user after an event is triggered as well as a small time [t_b] before the event. The technical manual seems to indicated that the deadtime assciated with operating in ROI mode can be reduced by the following factor:

$\frac{t_a + t_b }{\frac{N}{Sample Speed}}$ .

Where N is the number of points in the time window (ex. 2048 or 1024). Is it ok to describe this as:

$\frac{N'}{N}$

Where N' is the number of samples in the ROI and N is the same as before.

For example, if I were running at 5Gsps (200ps between samples), only recording 1024 samples per event and I had an signal that lasted 2ns, that means the signal would last 10 samples. If I set the ROI to only save 20 samples around this signal, would my Deadtime go to:

$\frac{10}{1024} * 30ns*1024 + 2\mu s = 2.3\mu s$ ? (The second portion of this equation comes from a response I recieved earlier, but I just want to make sure I understand this concept properly)

I recognize that the caveat is that this would work only if the signal was detected during acquistion, which leads to my next question. If no signals were detected in the 1024*200ps time frame in ROI mode, would the DRS4 go dead for 32us (using the factor = 1 from above equation), or would it dump the earliest events in the buffer for the more recent ones until it detects a signal?

Finally, I assume this functionality can only be utilized with custom electornics with the DRS4, not the evaulation/demo board, please let me know if this is the case.

Best,

Steven

664

Fri Mar 2 20:17:17 2018

ROI

You can achieve this functionality with the evaluation board, but you would have to make a special firmware for it.

Stefan

Steven Block wrote:

Hello,

$\frac{t_a + t_b }{\frac{N}{Sample Speed}}$ .

Where N is the number of points in the time window (ex. 2048 or 1024). Is it ok to describe this as:

$\frac{N'}{N}$

Where N' is the number of samples in the ROI and N is the same as before.

$\frac{10}{1024} * 30ns*1024 + 2\mu s = 2.3\mu s$ ? (The second portion of this equation comes from a response I recieved earlier, but I just want to make sure I understand this concept properly)

Finally, I assume this functionality can only be utilized with custom electornics with the DRS4, not the evaulation/demo board, please let me know if this is the case.

Best,

Steven

663

Fri Mar 2 18:08:55 2018

ROI

Hello,

$\frac{t_a + t_b }{\frac{N}{Sample Speed}}$ .

Where N is the number of points in the time window (ex. 2048 or 1024). Is it ok to describe this as:

$\frac{N'}{N}$

Where N' is the number of samples in the ROI and N is the same as before.

$\frac{10}{1024} * 30ns*1024 + 2\mu s = 2.3\mu s$ ? (The second portion of this equation comes from a response I recieved earlier, but I just want to make sure I understand this concept properly)

Finally, I assume this functionality can only be utilized with custom electornics with the DRS4, not the evaulation/demo board, please let me know if this is the case.

Best,

Steven

662

Tue Feb 27 18:12:32 2018

For applications which are critical on the dead time, one typically uses one ADC per DRS4 channel, and thus the dead time stays at 32us. If you multiplex two DRS4 channels into one ADC channel, then it goes to 32us.

Stefan

Steven Block wrote:

That is extremely helpful! Many thanks. One more question; If I were to take inputs from 2 channels at once, would that scale the dead time to 64us using your example?

Steven

Stefan Ritt wrote:

XML is very slow to write, and you are probably limited by that. Switch to binary mode, which is much faster. You will see in the end a maximum rate of ~500 Hz, and thus a dead time of 2ms, independent of the sampling speed. Note that you have only an evaluation board, which is optimized for ease of use. If you develop your own electronics, and do optimized readout, you can bring the deadtime down to 30ns x number of samples + 2us, or 32us if you read 1024 values from one channel.

Stefan

Steven Block wrote:

Hello All,

I am currently trying to figure out how to properly characterize the dead time of the DRS4 board. My most recent experiment to try and answer this question involved using an external trigger that can range from 1Hz to 2MHz. I fed this trigger into the DRS4 and collected 1000 samples with no input to any channels. I repeated this across the range of my external trigger by a factor of ten [10Hz, 100Hz, 1kHz...etc]. After I had saved these runs in XML format, I looked at the difference between timestamps on the events. Attached are my findings. Can someone offer an explanation for the periodic peaks? I am new to the DRS4 and don't really understand how it works. My guess is that there is a buffer that has to be emptied every so often, but if so, the buffer emptying time varies with the frequency of the trigger. I would ideally like to be able to know the relation of the dead time to a particular setting I change on the DRS4 such as locking the sampling speed or changing external trigger frequency.

Best,

Steven

661

Tue Feb 27 18:04:18 2018

That is extremely helpful! Many thanks. One more question; If I were to take inputs from 2 channels at once, would that scale the dead time to 64us using your example?

Steven

Stefan Ritt wrote:

Stefan

Steven Block wrote:

Hello All,

Best,

Steven

660

Tue Feb 27 17:04:12 2018

Stefan

Steven Block wrote:

Hello All,

Best,

Steven

659

Tue Feb 27 16:34:26 2018

Hello All,

Best,

Steven

Attachment 1: 1kHz.png

Attachment 2: 1MHz.png

Attachment 3: 10Hz.png

Attachment 4: 10kHz.png

Attachment 5: 100Hz.png

Attachment 6: 100kHz.png

658

Tue Feb 27 13:29:47 2018

WIndows Connection problem with drs507 SOLVED

Dear Steven, many thanks for this information, this is very useful. I know of people having problems on Windows 10, maybe this will also help them.

Stefan

Steven Block wrote:

Hello All,

I too have been struggling with trying to get the drs4 (507) to work on my windows machine and I found it to be a problem with the libusb library. My solution is as follows and has worked on multiple PC's. I ran this solution after I first plugged in the drs4 and installed 507.

Go to http://zadig.akeo.ie/ and install the corresponding software.

After that, you will need to plug in the DRS4 to your computer. From there go to ‘Options’, and select ‘List all Devices’.

Finally, choose the DRS4 evaluation board from the list and press install driver and let it run. You should be fine after that.

Best,

Steven

657

Tue Feb 27 13:17:00 2018

WIndows Connection problem with drs507 SOLVED

Hello All,

Go to http://zadig.akeo.ie/ and install the corresponding software.

After that, you will need to plug in the DRS4 to your computer. From there go to ‘Options’, and select ‘List all Devices’.

Finally, choose the DRS4 evaluation board from the list and press install driver and let it run. You should be fine after that.

Best,

Steven

656

Thu Jan 25 08:07:32 2018

problem with the drscl(drs507)

I have tried about 4 computers,only one worked fine.I truly want to know how others get this fixed,can you get in touch with them?

Stefan Ritt wrote:

This problem has been reported by several people, like elog:551

So far I could not solve it. On the computers at our lab it works find so I cannot reproduce and fix the problem. One suspicion I have is that the underlying libusb library needs to be updated. You can try to install the newest version from their website at http://libusb.info/, but I haven't tried it myself.

Stefan

chen wenjun wrote:

Hi! Stefan:

when I change a new computer(win7,64bit),I meet a problem that the drscl app cannot found the board! It shows"USB successfully scanned,but no boards found",but the drsosc runs well . when I connect to other win7*64bits computer,only one of them runs property! Is there any driver else I need to install?

Thank you!

Chen

655

Thu Jan 25 08:00:16 2018

problem with the drscl(drs507)

This problem has been reported by several people, like elog:551

Stefan

chen wenjun wrote:

Hi! Stefan:

Thank you!

Chen

654

Thu Jan 25 06:10:52 2018

drscl doesn't find eval board but drsosc does (Windows 7)

Hi! Jim:

It seems that I meet the same question with you ,and I am confused ,have you find out the reason about this problem?Or can you tell me how you deal with it?

Thank you very much!

chen

Jim Freeman wrote:

I cannot find the EVAL board using drscl version 5.06 while the drsosc works fine. I tried 2 different eval boards and 2 different computers and the same effect. I looked under device manager at the libusb and the drs4 was there, and checked the driver which was found to be up to date.

653

Thu Jan 25 05:24:05 2018

problem with the drscl(drs507)

Hi! Stefan:

Thank you!

Chen

652

Wed Jan 17 10:09:09 2018