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ID Date Authordown Subject
  293   Wed Sep 11 02:41:28 2013 Andrey KuznetsovUSB connection stops
Hi,

although I don't have a chance to test your code, it looks very similar to what I am using.

I can confirm that the DRS4 communication breaks down if the program talking to the DRS4 is closed abruptly or before is has a chance 
to properly execute "delete drs" where it closes the USB connection.

For me if I terminate the program that's using DRS4, the next time I might or might not be able to connect to the DRS4 because I would 
get a magic number or the program would just stop. The DRS4 eval board needs to be restarted via pulling the plug if the orange LED is 
not ON.

I have tried to power down the DRS4 board via software under SL6 linux, but the reality is that the DRS4 eval board is powered directly 
by the 5V USB rail off the computer, and you cannot software control that, you can only suspend the communication of the USB 
port/device.

So I don't have a solution to fix this issue, but my best advice is to change your software such that it calls "delete drs" to 
terminate the USB connection before you close or terminate the program.

Oh and I have not tried running multiple programs at the same time to see if that might be causing the issue as well. The usb library 
might simply error out saying the device is inaccessible because it's being used.

> Hello the DRS4 team,
> 
> I and some of my colleagues are using DRS4 evaluation boards (ver. 3) for the R&D of the Cherenkov Telescope Array project. During 
> our PMT measurements, we have encountered a problem which is probably related to USB connection. In fact, I cannot reproduce this 
> problem with my Linux virtual machine (Scientific Linux 5 64 bit), but other colleagues from three different universities in Japan 
> reported the same problem with their real machines.
> 
> === Short Summary ===
> DRSBoard::SetFrequency occasionally stops
> 
> === Environment ===
> - drs-3.0.0
> - Scientific Linux 5.5 (32 bit)
> - lib-usb-devel-0.1.12-5.1.i386
> 
> === Steps to Reproduce the Problem ===
> 1. Compile the attached file drs_simple.cpp with drs-3.0.0
> 2. Repeat the following command several times from a terminal
> 
> $ drs_simple -0.05 1000 ./outputfilename.dat true 2.
> 
> 3. The above command may stop. In that case, you need to kill the command by Ctrl-C.
> 
> === Comments ===
> - Once the command stops, we cannot run the above command properly.
> - If we unplug and plug the USB cable again, the command can be executed again.
> - It seems that the program stops inside DRSBoard::SetFrequency
> 
> I would very appreciate it if you could give me any advise. If you need further information, please let me know.
> 
> Akira
  753   Thu Jun 20 01:36:48 2019 Andrew PeckEvaluation firmware wait_vdd state

Dear Stefan,

I am working with others at UCLA on a custom made board built around the DRS4. We are in the process of writing firmware so I am adapting the readout state machine from the evaluation board firmware.

I see in the state machine of the eval board firmware that after a trigger is received, the FPGA goes into the start readout state and then into "wait_vdd", where the FPGA waits "~120 us for vdd to stabilize" before reading out the ADC.

Our application is sensitive to deadtime and this wait_vdd state adds very significantly.  I am trying to find anything explaining the necessity of wait_vdd in the documentation / elog and have only found so far your old forum posting, https://elog.psi.ch/elogs/DRS4+Forum/12

Does this forum posting explain wait_vdd or is there a another purpose that I have missed?

If this post is relevant to wait_vdd, does the advice of large capacitance and an LDO with fast transient response still apply or are there any new recommendations?

Thank you,

Andrew Peck

  755   Mon Jun 24 23:07:35 2019 Andrew PeckEvaluation firmware wait_vdd state

Dear Stefan, 

Thanks so much for clarifying this. We made wait_vdd a parameter controlled by software and will try to experiment with it to find some compromise between deadtime and the offset added by the droop in VDD. 

Best regards, 

Andrew

Stefan Ritt wrote:

Dear Andrew,

the posting you mention is still accurate. Any power supply will drop when you start the Domino wave, no matter how big your capacitor is. Unfortunately the output signal of the DRS4 scales with VDD. So if your VDD drops by 40 mV and you get a trigger and you immediately start the readout, the output baseline will also be shifted by about 40 mV. If you are sensitive to dead time, you can remove the wait_vdd state completely, but then you have to deal with varying baseline shifts. If you have narrow signals sitting on a broad baseline, you can correct for this by measuring the baseline outside your signal, then subtracting it before integrating your pulse. If you have lots of pile-up in your signals, it might sometimes be hard to evaluate the baseline on an event-by-event basis.

Stefan

Andrew Peck wrote:

Dear Stefan,

I am working with others at UCLA on a custom made board built around the DRS4. We are in the process of writing firmware so I am adapting the readout state machine from the evaluation board firmware.

I see in the state machine of the eval board firmware that after a trigger is received, the FPGA goes into the start readout state and then into "wait_vdd", where the FPGA waits "~120 us for vdd to stabilize" before reading out the ADC.

Our application is sensitive to deadtime and this wait_vdd state adds very significantly.  I am trying to find anything explaining the necessity of wait_vdd in the documentation / elog and have only found so far your old forum posting, https://elog.psi.ch/elogs/DRS4+Forum/12

Does this forum posting explain wait_vdd or is there a another purpose that I have missed?

If this post is relevant to wait_vdd, does the advice of large capacitance and an LDO with fast transient response still apply or are there any new recommendations?

Thank you,

Andrew Peck

 

 

  549   Wed Oct 26 21:15:35 2016 Alexey LubinetsProblems with DRS command line
Hello, everybody

I have installed the software for the DRS4 Evaluation Board.
When I run the DRS Oscilloscope, it works OK (at least, my computer "knows", that the board is connected). But when I run the DRS Command Line Interface, it writes "USB successfully scanned, but no boards found
No DRS boards found".
How can I manage with this problem? The drivers for the DRS Evaluation Board are installed.

Regards, Alexey Lubinets
  567   Thu Nov 24 00:40:38 2016 Alexey LubinetsPLL did not lock

Hello, everybody!

I installed DRSosc and DRScl. Command line works normally (at least, it can "see" the board). But when I start the oscilloscope, I have an error: "PLLs did not lock on USB board #0, serial number #...". In Info section I can see the board type = 9 (and in the error message I have "USB board #0").

After that I have a warning: "Board on USB0 has invalid voltge calibration. Only raw data will be displayed". I tried to execute voltage calibration using DRSosc and DRScl, but it did not help.

Did anybody face such broblems? Does anybody know, how to fix them?

Thank you. Alexey.

  570   Mon Nov 28 16:48:15 2016 Alexey LubinetsPLL did not lock

The serial number is 2586. This board is about two years old, and it might be in use (but I do not know exactly).

Stefan Ritt wrote:

Which serial number has the board? Has it been in use before or is it a new board?

Stefan

Alexey Lubinets wrote:

Hello, everybody!

I installed DRSosc and DRScl. Command line works normally (at least, it can "see" the board). But when I start the oscilloscope, I have an error: "PLLs did not lock on USB board #0, serial number #...". In Info section I can see the board type = 9 (and in the error message I have "USB board #0").

After that I have a warning: "Board on USB0 has invalid voltge calibration. Only raw data will be displayed". I tried to execute voltage calibration using DRSosc and DRScl, but it did not help.

Did anybody face such broblems? Does anybody know, how to fix them?

Thank you. Alexey.

 

 

  805   Thu Dec 17 09:29:43 2020 Alex Myczkodrs sources on github?
Are there plans to add the drs software to github? (asking because I have users @ethz.ch that want to use it on debian,
thus I'm creating official debian packages of it, if license allows so, but talking to upstream (the developers) would be
much easier on github (or irc) than on this "DRS4 Discussion Forum".

Best,
  863   Tue Feb 15 11:59:22 2022 Alex Myczkoapt install drs4eb

drs4b is now officially on these distributions:

https://repology.org/project/drs4eb/versions

enjoy

  678   Fri Apr 13 18:14:07 2018 Alessio BertiVoltage and Timing Calibration in drs_exam.cpp

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

  683   Wed May 2 10:44:17 2018 Alessio BertiPeak at 0 mV in traces

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

 

  685   Wed May 2 12:23:16 2018 Alessio BertiPeak at 0 mV in traces

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

Stefan Ritt wrote:

I note that your peak at zero is exactly twice as high as the bins left and right, so this looks to me like a binning problem in your histogramming. Maybe your bin #0 goes from -1mV to +1mV, which all other bins are just 1mW wide. Can you check that?

Stefan

Alessio Berti wrote:

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

 

 

 

  691   Tue May 8 12:15:54 2018 Alessio BertiPeak at 0 mV in traces

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

 

 

Stefan Ritt wrote:

I tried the following:

- trigger on a 10 MHz sine wave on CH0, CH1 was open

- run drs_exam.cpp program and write data.txt with a few events

- imported the event into Excel

- did a histogram on (empty) CH1

What I see is a nice Gaussian distribution centered around 1mV, but with no spike around zero. See attachment. So I still believe that you have either a binning or a rounding problem. Like you round value -0.99 to +0.99 all to zero mV, and 1.00 to 1.99 mV to one mV.

Stefan

Alessio Berti wrote:

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

Stefan Ritt wrote:

I note that your peak at zero is exactly twice as high as the bins left and right, so this looks to me like a binning problem in your histogramming. Maybe your bin #0 goes from -1mV to +1mV, which all other bins are just 1mW wide. Can you check that?

Stefan

Alessio Berti wrote:

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

 

 

 

 

 

  696   Mon May 14 09:21:29 2018 Alessio BertiWIndows Connection problem with drs507 SOLVED

Hi,

I have a machine with Windows 10 and the solution provided by Steven works fine. To give more details, the driver installed in my case is WinUSB (i.e. libusb, v6.1.7600.16385).

Cheers,

Alessio

Alec Shackleford wrote:

Thank you for this fantastic solution. I had almost reinstalled windows 7 to see if that would solve the issue!

 

All the best,

Alec

Stefan Ritt wrote:

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

 

 

 

  695   Wed May 9 14:07:10 2018 Alec ShacklefordWIndows Connection problem with drs507 SOLVED

Thank you for this fantastic solution. I had almost reinstalled windows 7 to see if that would solve the issue!

 

All the best,

Alec

Stefan Ritt wrote:

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

 

 

  292   Tue Sep 10 10:31:30 2013 Akira OkumuraUSB connection stops
Hello the DRS4 team,

I and some of my colleagues are using DRS4 evaluation boards (ver. 3) for the R&D of the Cherenkov Telescope Array project. During 
our PMT measurements, we have encountered a problem which is probably related to USB connection. In fact, I cannot reproduce this 
problem with my Linux virtual machine (Scientific Linux 5 64 bit), but other colleagues from three different universities in Japan 
reported the same problem with their real machines.

=== Short Summary ===
DRSBoard::SetFrequency occasionally stops

=== Environment ===
- drs-3.0.0
- Scientific Linux 5.5 (32 bit)
- lib-usb-devel-0.1.12-5.1.i386

=== Steps to Reproduce the Problem ===
1. Compile the attached file drs_simple.cpp with drs-3.0.0
2. Repeat the following command several times from a terminal

$ drs_simple -0.05 1000 ./outputfilename.dat true 2.

3. The above command may stop. In that case, you need to kill the command by Ctrl-C.

=== Comments ===
- Once the command stops, we cannot run the above command properly.
- If we unplug and plug the USB cable again, the command can be executed again.
- It seems that the program stops inside DRSBoard::SetFrequency

I would very appreciate it if you could give me any advise. If you need further information, please let me know.

Akira
  297   Wed Sep 25 14:42:00 2013 Akira OkumuraUSB connection stops
Hello Andrey,

Thank you for your advise. But we never terminated the program before closing and deleting the DRS object. What we did was just executing the program multiple times 
repeatedly.

Akira
  783   Mon Mar 23 15:03:28 2020 Ajay KrishnamurthyUSB trigger issue

Hello,

I had forgotten to disable the turn off the power to the USB drive on Windows and DRS4 stopped triggering. Now, we are all on quarantine and I am unable to reset the board to normal function. Are there any commands to reset the board remotely. I tried all of the default Windows based solutions such as disable USB port etc., but I am unable to do this. Only thing that has worked in the past is manually replugging the USB but I do not have the option to do that currently. Please help.

Thanks,

Ajay 

  557   Thu Nov 10 04:41:24 2016 Abhishek RajputBreak Statements in DRS4 Binary to ROOT Macro

Hello,

I recently modified the binary to ROOT convertor written by Stefan (https://midas.psi.ch/elogs/DRS4+Forum/361) so it can decode data taken with any channel or set of channels  on the DRS4. In the process of testing this modifed version for data taken on all 4 channels, I encountered problems with decoding some of the event data. More specifically, upon hitting a certain event in some channel, the histograms for that channel would no longer be filled and the histograms for subsequent channels would not be filled with any event at all. 

After considerable bug hunting, I discovered the source of this problem was due to the break statement in the following code extract from the ROOT to binary macro:

 for (n=0 ; n<5 ; n++) {
      // read event header
      i = fread(&eh, sizeof(eh), 1, f);
      if (i < 1)
         break;

For some events apparently, the event header fails to be read properly (fread line returns 0 in this case). Moreover, when I used the feof and ferror functions on a particular file I was testing, the feof function returned a value of 1.

So my questions deal with two scenarios.

Firstly, in the event of an fread error, is a break statement is necessary? Is it not possible to skip the voltage data for those events whose event header fails to be read properly? Or is it the case that when some "corrupted" event header is encountered, all waveform data subsequent to that event is likewise corrupted? If the former is the case, is it advisable to replace the break condition with an fseek line that advances the position indicator of the stream by an additional 2052*n_channels + 32 bytes (in accordance with the binary file specifications of page 25 on the DRS4 manual) so that the next set of voltage data can be read? 

Secondly, in the case of an end of file error, does there exist any possible solution? Or is such an error an indication of a faulty drs4 channel or corrupted binary file? 

Any help with the aforementioned issues would be greatly appreciated.

 

Abhishek

 

  560   Thu Nov 10 19:24:52 2016 Abhishek RajputBreak Statements in DRS4 Binary to ROOT Macro

Hello,

I am wondering why the code should be changed to i < sizeof(eh), since doesn't fread(&eh,sizeof(eh),1,f) return 1 in this scenario? I've confirmed with a cout statement that this is the case, so this break condition will therefore always trigger as sizeof(eh) is 32 bytes. 

Either way, I believe I figured out my problem. In my revised version of your code, I had two nested loops, the outer one being a loop over the channels and the inner one being a loop over the events. However, I really should have been doing the reverse considering the binary structure of the file.  Otherwise, the end of the file will be reached for only a single iteration of the channel loop if I choose to loop through all the events in the data file.

Once I modified the code to have the outer loop be over all the events and the inner one be over all the channels, I no longer suffered from breaks in the loops. 

Many thanks for your assistance. 

Abhishek 

Stefan Ritt wrote:

Hi,

fread() returns the number of bytes read and zero (I believe) if there is an end of file. So this break statement is a simple end-of-file test. There might be other erros such as hard disk failures, but these are extremely rare. 

If course the file should not end in the middle of an event header. If it does, it means the file is corrupted and truncated, and we should not continue to read that file, that's why there is the break. The internal file is just a series of bytes, it does not know about the event header, so there will be no "error" if we have for example a missing event header but a voltage array. To be correct, the code should actually read

for (n=0 ; n<5 ; n++) {
      // read event header
      i = fread(&eh, sizeof(eh), 1, f);
      if (i < sizeof(eh))
         break;

Hope this helps,

Stefan

Abhishek Rajput wrote:

Hello,

I recently modified the binary to ROOT convertor written by Stefan (https://midas.psi.ch/elogs/DRS4+Forum/361) so it can decode data taken with any channel or set of channels  on the DRS4. In the process of testing this modifed version for data taken on all 4 channels, I encountered problems with decoding some of the event data. More specifically, upon hitting a certain event in some channel, the histograms for that channel would no longer be filled and the histograms for subsequent channels would not be filled with any event at all. 

After considerable bug hunting, I discovered the source of this problem was due to the break statement in the following code extract from the ROOT to binary macro:

 for (n=0 ; n<5 ; n++) {
      // read event header
      i = fread(&eh, sizeof(eh), 1, f);
      if (i < 1)
         break;

For some events apparently, the event header fails to be read properly (fread line returns 0 in this case). Moreover, when I used the feof and ferror functions on a particular file I was testing, the feof function returned a value of 1.

So my questions deal with two scenarios.

Firstly, in the event of an fread error, is a break statement is necessary? Is it not possible to skip the voltage data for those events whose event header fails to be read properly? Or is it the case that when some "corrupted" event header is encountered, all waveform data subsequent to that event is likewise corrupted? If the former is the case, is it advisable to replace the break condition with an fseek line that advances the position indicator of the stream by an additional 2052*n_channels + 32 bytes (in accordance with the binary file specifications of page 25 on the DRS4 manual) so that the next set of voltage data can be read? 

Secondly, in the case of an end of file error, does there exist any possible solution? Or is such an error an indication of a faulty drs4 channel or corrupted binary file? 

Any help with the aforementioned issues would be greatly appreciated.

 

Abhishek

 

 

 

  566   Wed Nov 23 08:17:23 2016 Abhishek RajputPotential Incorrect Timing Calibration for DRS4 Data

Hello,

I was running through a particular binary file containing data taken on all 4 channels of the DRS4 and printing out the value of the first time sample for each channel (per event). While doing so, I noticed that some of these times were negative. For this dataset, channel 1 was chosen as the reference channel (which is the default setup in Stefan's DRS4 macro).  From my understanding, the calibration procedure delineated in the DRS4 manual and shown in the code below is supposed to sync the timing of each channel relative to sample 0. However, this does not appear to be the case for when I print out the time value of the first sample, I notice that only channel 1's 0th sample is set to 0. The first sample for the other channels is nonzero (and most often negative). 

Even more strange is when I test another 4-channel dataset with the same code, this issue does not appear. More specifically, the first time sample on each waveform on all channels is set to 0, as should be the case.

My question is therefore whether or not the timing calibration varies from dataset to dataset. My initial thought was that this should not be the case, but I have two different data sets taken on the same set of channels which give different timing calibration results. Are there any circumstances under which this behavior can happen? 

for (ch=0 ; ch<5 ; ch++) {
         i = fread(hdr, sizeof(hdr), 1, f);
         if (i < 1)
            break;
         if (hdr[0] != 'C') {
            // event header found
            fseek(f, -4, SEEK_CUR);
            break;      
         }
         chn_index = hdr[3] - '0' - 1;
         fread(voltage, sizeof(short), 1024, f);
         
         for (i=0 ; i<1024 ; i++) {
            // convert data to volts
            waveform[chn_index][i] = (voltage[i] / 65536. - 0.5);
            
            // calculate time for this cell
            for (j=0,time[chn_index][i]=0 ; j<i ; j++)
              time[chn_index][i] += bin_width[chn_index][(j+eh.trigger_cell) % 1024];            
         }
      }
    
      // align cell #0 of all channels
      t1 = time[0][(1024-eh.trigger_cell) % 1024];
      for (ch=1 ; ch<4 ; ch++) {
         t2 = time[ch][(1024-eh.trigger_cell) % 1024];
         dt = t1 - t2;
         for (i=0 ; i<1024 ; i++)
            time[ch][i] += dt;
      }
ELOG V3.1.4-bcd7b50