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

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: 

.

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

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:

? (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

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

Hi,Stefan:

  recently,whtn I study the drs.cpp code ,I found that  the buffer[1] is char but the addr and the base_addr are all unsigned int,isn't there any problem that the addr may be cut off to 8 bits? Also ,I found that the data fpga recieved from the usb is 16 bits,so how can fpga get the true 32bits address from the PC.

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. 

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

Helo
I'm building an application for reading waveforms from the DRS4 board to PC. However, I am having problems reading calibration data from EEPROM on DRS4 board. The calibration data is read through the function reference:
void DRSBoard :: ReadCalibration (void)
...
      ReadEEPROM (1, buf, 1024 * 32);
      for (i = 0; i <8; i ++)
         for (j = 0; j <1024; j ++) {
            fCellOffset [i] [j] = buf [(i * 1024 + j) * 2];
            fCellGain [i] [j] = buf [(i * 1024 + j) * 2 + 1] / 65535.0*0.4+0.7;
         }
      
      ReadEEPROM (2, buf, 1024 * 32);
      for (i = 0; i <8; i ++)
         for (j = 0; j <1024; j ++)
            fCellOffset2 [i] [j] = buf [(i * 1024 + j) * 2];
...
The Calibrate Waveform is performed by:
int DRSBoard::CalibrateWaveform(unsigned int chipIndex, unsigned char channel, unsigned short *adcWaveform, short *waveform, bool responseCalib, int triggerCell, bool adjustToClock, float threshold, bool offsetCalib)
.....
         for (j = 0; j < n_bins; j++) {
            value = adcWaveform[j] - fCellOffset[channel+chipIndex*9][(j*skip + triggerCell) % kNumberOfBins];
            value = value / fCellGain[channel+chipIndex*9][(j*skip + triggerCell) % kNumberOfBins];
            if (offsetCalib && channel != 8)
               value = value - fCellOffset2[channel+chipIndex*9][j*skip] + 32768;
...
. Because the calibration data reads incorrectly, the Calibrate Waveform does not do it.
Can read calibration data from EEPROM by any command via Oscilloscope application or DRS Command Line Interface application?
Thank you for your help!!!!

Hello everyone, 

The new read_binary.cpp code 

I will be very glad if anyone can help with the old version of read_binary.cpp code. The latest version I saw online was updated on June 30th, 2014, but I need the old version of the code to compare what changes were made in the latest version. This will help me to modify it and be able to read my data successfully. Thanks

Hi, 

I would like to save the waveform in a .dat binary file using drs_exam.cpp.

I know the distributed software allows us to save as binary files with the save button, but I currently need to save multiple runs using a script.

I've seen that drs_exam.cpp can save the waveform as .txt files.

Is there any .cpp file or function that allows us to save the waveforms in binary format (.dat)?

Thank you for your help. 

Hi,

we modified drs_exam.cpp to read all 4 channels from the DRS4 and apply directly the spike removal (taken from Osci.cpp) during the acquisition phase. For test purposes, we don't save the data showing spikes and we focus on the data not having spikes (even if at the end we end up having triple and quadro spikes which are not removed by the spike removal routine, but they are rare). With this modified program we wanted to characterize the noise of the DRS4, so we took 30000 events at 5GSPS, triggering on channel 1 with a 10 MHz sine wave with 100 mV_pp (trigger level set at 10 mV), while channels 2,3 and 4 were left open without any input.

We then took a look at the data and plotted the noise histograms for channels 2,3 and 4, which you can find attached (without offset correction, named zero_peak_after_spike_removal_ch*.png). For completeness, we also attached the plot from ch1 (the sine wave). The selections in time and amplitude we applied had the goal to remove the high oscillations in amplitude occurring in the first and last samples and to discard the quadro spikes we had in the data.

We see that there is a peak at 0 mV in all histograms from all channels and scanning through the data, we saw that indeed the value 0 mV is stored many times for each event, thus originating the peak we see in the histograms. We also applied an offset correction to the data (taking the average of the first three most occuring amplitudes) of channels 2 (as an example) and the problem seems to be only partially removed.

We also noticed that this peak at 0 mV is present also when we acquired the data from the DRS4 with DRSosc saving the data in binary format.

So we had the following questions:

- why is the DRS4 saving so many times the value 0 mV (exactly 0 mV)?

- is there any way (in our case through software, preferably at acquisition time) to solve this problem?

Thank you for the help and best regards,

Alessio & Davide

Hi,

thank you for the quick reply. All the bins in the previous histograms have the same width. We also tried to plot the noise histogram for channel 2 with more bins (i.e. 1000, so that we can see almost discrete values), and the peak is still there.

Alessio & Davide

Hi,

we were trying to implement an automatic way to calibrate our DRS4 both in voltage and in time (we have the V5 Evaluation Board). We started from drs_exam.cpp and tried with the following lines:

/* set input range to -0.5V ... +0.5V */

b->SetInputRange(0);

b->CalibrateVolt(NULL);
b->CalibrateTiming(NULL);

While the timing calibration seems to work (we checked with drsosc executable), the voltage calibration in our test program seems not to do the same as in drsosc when pressing the button "Execute Voltage Calibration". Specifically we think that no primary calibration, secondary calibration or spike removal is applied when calling CalibrateVolt(). It seems that the methods to perform those tasks are implemented in Osci.ccp/Osci.h, but drs_exam.cpp uses objects of the class DRS (i.e. defined in DRS.cpp and DRS.h).

Is there a way to execute the voltage calibration in drs_exam.cpp in the same way performed within drsosc?

Cheers,

Alessio

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?

Hi Stefan:

  I'm still confused that althought the 8 bits buffer is enough,the FPGA receive the command through the uc_data_i register which is 16 bits wides.As we can see in the firmware, the locbus_addr is 32 bits wides. Does it means the locbus_addr[31:8] are always '0' because the address in buffer is only 8 bits. Does it means the usrbus_status_sel and usrbus_ram_sel are also '0' all the time .

thanks!

chen

Hi Stefan,

following your example, we tried to perform the same measurement, using drs_exam and taking 1000 events. The results we obtained are in the plots attached (both in log and linear scale). We tried two different binnings:

    - the first is the same as the one used in your example, that is 0.1 mV (corresponding to the plots having 81 bins)

    - the second is a more wide binning equal to 0.35 mV, that is (2^(-11.5)) mV, 11.5 being the effective number of bits given in the DRS4 spreadsheet (corresponding to the plots having 23 bins)

With the fine binning we see that in the bin centered around 0 there is a little excess of events (the effect is more visible in the log scale histograms). This excess is not present in the wide binning case.

Is the problem we had before (and also here in the fine binning case) lying in the fact that we were trying to have bins with a width smaller than the effective resolution of the instrument (0.35 mV)?

We also noticed that in drs_exam, the values for the waveform are printed in the ASCII file with 1 digit after the decimal point, but when trying to print more digits the resolution is not improved (i.e. the decimal digits from the second one on are 0). This means that the values are rounded to a resolution of 0.1 mV when they are saved through the GetWave() routine (and in fact the member fPrecision is set to 0.1 -mV- in DRS.cpp, line 7502, and also in DRS.h, line 757, GetPrecision() returns 0.1). Why is that so? How does it reconcile with the effective number of bits giving a resolution of 0.35 mV?

Thank you,

Alessio & Davide

Dear All,

I'm troubleshooting a board which uses the DRS4 and adopts an analog front end very similar to the evaluation board. As a result, we rely on the eval board as a reference. In doing so we've encountered an issue in the manual:

The high resolution photo in Figure 1. is useful, but it seems to correspond to an older version of the board. For instance, the RF switch can't correspond to the schematics of Rev5.1 in the appendix.

Request: Could the manual be updated with a high resolution image of Rev5.1. Also, could a high resolution of the bottom side of the board be included in the manual? This is desirable since it has the version number and contact information, so it will remove any ambiguity about what board you're looking at and what schematics you should refer to.

A second question, which might be overly broad: what is the impact of installing the optional components (marked * in the schematics) on the analog front end? Why are a lot of these left uninstalled on the eval board?

Thanks,

Sean

Dear Stefan,

I am using an DRS4 board to test the signal from an scintillator detector; It has connected well to the computer on DRS Oscilloscope (Figure 1). Now, I am having a problem of developing from the code of the drs_exam program, because the DRS4 board has not connected to the computer when translation the drs_exam program (Figure 2). Before running the drs_exam program, I copied the libusb-1.0.lib file to the computer's "C: \ Program Files \ Microsoft SDKs \ Windows \ v7.0A \ Lib" folder. Can you show me how to solve this problem?

Figure 1.

Figure 2.

Thank you very much!

Best Regards,

Chuan

Dear all,

I have been wondering what the maximum analog input voltage for the DRS4 V5 evaluation board is. It came with a sticker indicating that it is "2.5V pk Max". On the other hand, when checking the manual (https://www.psi.ch/drs/DocumentationEN/manual_rev50.pdf), it says maximum allowed is 10V DC or even 30V for short pulses. I foresee an application where I cannot make sure that pulses stay below 2.5V, so the correct value will be quite important for me.

Best,
Julian

Dear Stefan,

We are using an DRS4 board V5.1 for building a metering system for the scintillator detector by a Labview program. The program was built based on the functions in DRS.cpp and it reads data from channel 0 very well (Fig 1). Now, I am having a problem with the data acquisition from DRS4 board. The data acquisition speed on this program is only about 30-50 Acq / s, while using the DRS Oscilloscope that of about 300-400 Acq / s.

When the program was installed with fDominoMode = 0 and fDominoActive = 0, the data acquisition speed was about 300-400 Acq / s. However, the waveform is inaccurate.

I do not know if I installed the wrong function! Can you show me how to solve this problem?

In the Labview program, functions (corresponding to functions in DRS.cpp) are called with the following parameters:

InitFPGA();

SetMultiBuffer(0);

fROFS = 1.6;              // differential input range -0.5V ... +0.5V

fRange = 0;

SetDAC(fDAC_ROFS_1, fROFS);

 fCommonMode = 0.8;        // 0.8V +- 0.5V inside NMOS range

SetDAC(fDAC_CALP, fCommonMode);

SetDAC(fDAC_CALN, fCommonMode);

SetDAC(fDAC_BIAS, 0.70);

/* set default number of channels per chip */

SetChannelConfig(0, fNumberOfReadoutChannels - 1, 8);

// set ADC clock phase

      fADCClkPhase = 0;

      fADCClkInvert = 0;

   // default settings

fMultiBuffer = 0;

   fNMultiBuffer = 0;

   fDominoMode = 1;

   fReadoutMode = 1;

   fReadPointer = 0;

   fTriggerEnable1 = 1;

   fTriggerEnable2 = 0;

   fTriggerSource = 0;

   fTriggerDelay = 0;

   fTriggerDelayNs = 0;

   fSyncDelay = 0;

   fNominalFrequency = 1;

   fDominoActive = 1;

// load calibration from EEPROM

ReadCalibration();

...

SetDominoMode(fDominoMode);

   SetReadoutMode(fReadoutMode);

   EnableTrigger(fTriggerEnable1, fTriggerEnable2);

   SetTriggerSource(fTriggerSource);

   SetTriggerDelayPercent(0);

   SetSyncDelay(fSyncDelay);

   SetDominoActive(fDominoActive);

   SetFrequency(fNominalFrequency, true);

   SetInputRange(fRange);

SelectClockSource(0); // FPGA clock

// disable calibration signals

   EnableAcal(0, 0);

   SetCalibTiming(0, 0);

   EnableTcal(0);

   // got to idle state

   Reinit();

////////

SetFrequency (1,false);

settranspmode (1);

setinputrange(0);

EnableTcal (0,-,-);

EnableTrigger(1, 0);

SetTriggerSource(0);

SetTriggerLevel(0);

SetTriggerPolarity(false);

SetTriggerDelayNs(512);

// in loop of read data from DRS4:

 {

StartDomino();

while (b->IsBusy());

TransferWaves(0, 8);

GetTime(0, 0, b->GetTriggerCell(0), time_array[0]);

GetWave(0, 0, wave_array[0]);

}

Thank you very much!

Best Regards,

Chuan