> a) Calibration:
> I am using 4 boards daisy chained. To achieve optimal time resolution I did first a voltage calibration and right afterwards a time calibration. For all 
> boards after the master I am not sure how to do it.
> After setting the flag "Configure multi-board daisy-chain" in the config menu, all the slave boards set the flag "use external reference clock".  By 
> hitting the voltage calibration button, the slave boards unset this flag. Is it true, that I have to re-set this before doing the time-calibration right 
> afterwards?

Please do NOT do any calibration in multi-board mode. This will not work. Calibrate the boards separately, then activate the multi-board mode. Please note that the timing between the boards is not better 
than ~50 ps. This is a limitation of the FPGA clock generators. If you need better timing, you have to feed an external clock into one channel of each board (leaving only 3 channels for DAQ). The upcoming 
WaveDREAM board will have 16 channels per board, so building bigger DAQ systems will be much easier (and more precise).

> b) getting the right times in binary format:
> To get the time out of the time width (i.e. the t_ch[i]) you sum up in your documentation from j=0 to j=i (see attachment). In your example code 
> read_binary.cpp (line 113) you sum from j=0 to j=i-1. Since you get the the bin with in the binary file, I guess that the example code is correct one?

Yes, I will correct the documentation.

Cheers,
Stefan

Hello,

what is the abbreviation of DRS?

Thanks and kind Regards,

Moritz

Domino Ring Sampler. 

Dear Stefan Ritt,

I am using a DRS4 v5 to do timing measurements of Positron lifetime. I use the DRS Oscilloscope with triggering on 2 channels when I have a coincidence. Attached is a picture with all the setting that I use. When I use the DRS4 for a long measurements of 5 million events for a couple of hours, the DRS Oscilloscope stops showing any signal .After the first restart of the program I get a strange signal which is at the bottom of the scope range of voltage picture below(in the picture I changed the vertical positions of the channels for better viewing). Only after a couple of DRS Oscilloscope restarts and USB reconnections do I get the results again.

I currently am using another DRS4 v5 and the same situation occurs again although with lower frequency.

What can I do to solve this problem?

thank you very much,

Daniel

Dear Daniel,

sorry my late reply, I'm pretty busy these days. The behavior you report has not been seen before, but I guess no one tried to take such long runs of data yet. Can you confirm that the problem also occurs without writing data to disk, or is it disk-related? I guess you use it under Windows 7, right?

Stefan

Dear Stefan Ritt,

Yes I use Windows 7, If the DRS Oscilloscope program stays on for a couple of hours without saving the data, the problem will occur. It seems it happens more often when there is data writing and when the rate of events is slow, about 100 events per second, at high rates it almost doesn't happen. Can it be temperature related?

Daniel

Then it seems that there is some USB communication problem. I heard this also from other people, that the USB data transfer under Windows has sometimes problems. I develop and run the board under Mac OSX, and there the same software runs for days without problem. So I guess it's related to the underlying libusb lib which is used by the DRS oscilloscope, on which I have no influence. So the only advice I can give is to take shorter series of data. Anyhow the board is not considered a full DAQ system, just an "evaluation board" which means one can try the DRS4 chip and play with it. For serious business one should build own electronics with the chip. Anyhow we are currently developping an Ethernet board which allows much faster acquisition rates, so USB will be obsolete some day. Nevertheless I will try to reproduce your problem and see if I can do anything. At what trigger rate does it show up most prominently?

Stefan

I tried this night to run the board at a 10 Hz rate with an external pulser, without writing, and it did not freeze after ~14 hours of running on Mac OSX. This night I will try again with writing.

Stefan

Even with writing for one night no problem (see below). Have you checked how big your data file is? I guess there is a limit under Windows of 2 GB. If that's the case, you have to write shorter files.

Hi I have also positron annihilation system based on DRS4v4 cards. Its running several weeks, sometimes months, without freezing in windows7 64bit system (Pentium Core Quad 2Ghz, 4GRam).  Problem was when widows was trying to install updates and restarted PC. In beginning I had some problem with memory leak in my application, but it was simple seen in task manager that application memory was rising and was need to find memory leak in application code. Now I remember card was sometimes freezing when room air conditioning with 2kW was starting and high electricity pulses were reason of USB problems, it helped to put air conditioner and PC in different power line input. Hope it help to solve zour problems.

Martin

At hight rates I worked with files of up to 20 GB so I don't think this is the problem.

I will try to run it under Ubuntu and see if i can recreate the problem.

Thank you very much for the quick responses and help.

I too have air conditioning in the room, not sure to which power line it is connected, but I'll try to check this aswell.

Thank you very much.

I made a pre-compiled package for Mac OSX 10.8 (Mountain Lion), so one should be able to install the DRS Oscilloscope software with one mouse click on a recent Mac.

The Makefile in the tar ball now also supports OSX 10.8, so one could even compile it from the sources on a Mac, after libusb-1.0 and wxWidgets have been installed. That might then also work on older versions of OSX.

In addition, the software has been adaptes so that it compiles nicely on a Raspberry Pi (http://www.raspberrypi.org), a screenshot has been attached. Together with a Raspberry Pi and an old screen, the evaluation board is one of the cheapest available oscilloscopes.

In the attachement you will find a working DC-coupled input stage to the DRS4 chip. The bandwidth of this design is about 700 MHz, the gain is 1.

The upper version does not have an additional input buffer. This is not a very "clean" design, since the differential driver has an input impedance of 150 Ohm, which together with the 75 Ohm termination resistor gives about 50 Ohm termination. 

The lover version has an additional input buffer, which nicely decouples the input from the differential driver, so a proper 50 Ohm termination can be used at the cost of additional power for that buffer.

The COM common mode voltage and the OFS voltage have to be set according to the required input range, so that ranges such as 0V...1V, -0.5V...+0.5V, -1V...0V can be used. The COM voltage can be high impedance (simple resistor divider), while the OFS voltage needs to be low impedance (fast active buffer). The analog switch ADG918 can be used to digitize a precise calibration voltage CAL+, which can then be used for precise gain calibration of the DRS4 sampling cells.

The current version of the DRS readout example program drs_exam.cpp has two problems:

1. The sampling frequency cannot be changed, it will always stay in the region around 5 GSPS
2. The waveform obtained by GetWave is rotated such that the first DRS cell corresponds to the first array bin

Both problems have been fixed and the fix will be contained in an upcoming software release.

HI,

We are using the DRS4 Board in the EUDAQ framework [1]. We wrote a a Producer based on the software of the evaluation board, which is using the DRS class/header/src files.

In order to make it work we needed to compile it with a shared object file. [2]

Would it be possbile to include a shared object in the 'official' release? 

Cheers

Felix

[1]https://telescopes.desy.de/EUDAQ

[2]https://github.com/veloxid/DRS4-v5-shared

Hi Felix,

the distribution does not contain any binaries, since there are too many Linux distributions around, so everybody compiles from the sources under Linux. Do you want me to just add libDRS.so to the official Makefile? Actually you are the first one asking for this. Would it be beneficial to have this in the distribution, or can you just maintain your own Makefile in the github repository?

Stefan

Hi Stefan,

That's fine for me. I thought it might be interesting for others as well..

Cheers

Felix

Anyhow it would be nice if you just post your Makefile here, which runs with the standard distribution, so people can use it if needed.

Stefan

Yes of course no problem.

You can download via github https://github.com/veloxid/DRS4-v5-shared and I also put it in the attachment.

It's tested with Ubuntu, Fedora and RHEL.

For mac OSX one needs to create a dylib out of the so file.

Cheers

Felix