Have a look here: elog:361

Hi Stefan,

This is absolutely perfect.

Thanks,

Will

Hi,

https://forge.physik.rwth-aachen.de/projects/drs4-rwth

Not sure about their licensing, but is it possible to add latch delay support to official firmware ?

Best regards

Martin

I put that on the wish list, but I won't have time for that in the next months.

Stefan

Hi,

I would like to use the DRS4 board with LabView for fast readout.
Do you know anyone who has written a VI for that?

Thanks,
Christian

Hello,

Did you start to write some VI to interface DRS4board with labview ?

i also have in mind to do that.I am surprised that nobody alraedy did it since there is no answer toyour question

gerard

Not inside the board. Each channel has a single discriminator. You can select to trigger on a rising or falling edge, but you don't have two levels. What you can do however is to make an external trigger, like using old NIM logic. You can make discrimaiton with different levels and use a coincidence unit to combine them. Then feed the trigger into the external trigger input of the evaluation board (5V TTL level, not NIM level!).

Stefan

Hi

We are working with the DRS 4 V5 version and we investigated an issue with the trigger at rates below ~120 Hz.

As long as we have a trigger rate of more than 125 Hz. everything seems to work fine and we are recording more or less all events.

As soon as we go lower in input trigger rate to 100Hz, we see a drop in trigger rates to approx 15 - 20 Hz.

When we use the new firmware we can see that the busy signal is  0 for much longer times than usual up to .5 seconds.

We made a plot of input trigger rate vs trigger rate of drs: https://plot.ly/~simon.corrodi/316

In the  oscilloscope plots one can see the the trigger in in yellow and the trig out from drs board in blue.

Do you have any idea what could be the reason?

We also

Hi,

We did a further investigation of this problem:

We figured out that this issue seems to be related to the kernel.

We tested it now on two machines with Ubuntu 14.04.2 LTS (kernel 3.16.0-41), one with RHEL 6.6 (kernel 2.6.32) , one with Fedora 20 (kernel 3.18.7) and one with Mac OSX. We see this issue  with the Ubuntu and the fedroa  machines.Both have a kernel above 3.0 while RHEL has a kernel of 2.6

We can repoduce the problem on all input channels as a trigger. 

I will try to find out what could be the cause of it.

Cheers

Felix

Hello everybody!

After some times i init my board, or if i stop the program during the acquisition, i get the error message "Invalid magic 0000". The only way i can solve this problem is to physically disconnect and plug in again the USB cable.

What's the point? Is there a bash command / code i could use to reset it?

Thank you very much

Under linux, many people observed that the USB connection is unstable to the evaluation board. This must be related to the linux USB stack, since my code runs fine under MacOSX and Windows, where I use the same USB library (libusb-1.0). So I can't do anything from my side. Baybe the linux system has some tools to reset an USB endpoint. I googled it and found some proposals here:

https://askubuntu.com/questions/645/how-do-you-reset-a-usb-device-from-the-command-line

Regards,
Stefan

Hello, thanks for your answer. Unluckily if i try to reset in this way it keeps hanging

musb_write: requested 10, wrote 0, errno -7 (Unknown error 18446744073709551609)
musb_read error 0
musb_write: requested 10, wrote 0, errno -7 (Unknown error 18446744073709551609)
musb_read error 0
Invalid magic number: 0000
musb_write: requested 10, wrote 0, errno -7 (Unknown error 18446744073709551609)
musb_read error 0
musb_write: requested 10, wrote 0, errno -7 (Unknown error 18446744073709551609)
musb_read error 0

I also tried with sudo tee /sys/bus/usb/drivers/usb/unbind and binding again; same thing happens. It seems the board needs to be reset when this happens. Is there a way to do that - to reset the board instead of usb?

Thank you

Hello, thanks for your answer. Unluckily if i try to reset in this way it keeps hanging

musb_write: requested 10, wrote 0, errno -7 (Unknown error 18446744073709551609)
musb_read error 0
musb_write: requested 10, wrote 0, errno -7 (Unknown error 18446744073709551609)
musb_read error 0
Invalid magic number: 0000
musb_write: requested 10, wrote 0, errno -7 (Unknown error 18446744073709551609)
musb_read error 0
musb_write: requested 10, wrote 0, errno -7 (Unknown error 18446744073709551609)
musb_read error 0

I also tried with sudo tee /sys/bus/usb/drivers/usb/unbind and binding again; same thing happens. It seems the board needs to be reset when this happens. Is there a way to do that - to reset the board instead of usb?

Thank you

There is no other way to reset the board. As I said, people running this under Windows or MacOS are fine, so maybe this calls for a change of OS.

 A new software verison for the DRS4 Evaluation Board has been has been released. Version 2.1.3 adds a switch for the input range of the DRS4 board. Once can choose between -0.5V...0.5V and 0V...1V:

A board firmware update is not necessary for this. It was originally planned to have even a negative range -1V...0V, but this is not possible with the current board design. People who want to record negative pulses have to use an inverter to produce positive pulses. In a future version of the board it might be possible to include this functionality since this is determined by the analog front-end and not the DRS4 chip.

Hello,

It is not quite clear to me yet how the input range is only determined by the front end and not the DRS4 chip. According to the datasheet, the selection of ROFS determines whether the input differential range is -0.5V to 0.5V (ROFS=1.55V) or 0V to 1V (ROFS=1.05V) or -0.05V to 0.95V (ROFS=1.1V).

As far as I understand, the input differential voltage cannot go further below -0.55V since the maximum ROFS voltage is 1.6V according to the datasheet).

Also in the DRS4 evaluation board 5.1 design, the output of the differential amplifier is AC coupled to the DRS4 chip.

I'd appreciate a lot your help.

Regards,

Matias

To achieve an input range of -1V to 0V, you need an external buffer which can shift this range into the DRS4 range of -0.5V to +0.5V. This external buffer has then to operate with bipolar power supplies, like -2.5V to +2.5V, which are not present on the evaluation board.

Best regards,
Stefan

Hi Stefan,

    I read in the DRS datasheet that the input bandwidth if 950MHz. However, it also says the output bandwidth in the transparent mode is 50MHz. Since in the transparent mode the input is routed to the output, does it mean the input bandwidth also gets reduced in the transparent mode? I don't know how the transparent mode works inside the chip of course, but this value would be important since if the hardware discriminators are connected to the output of DRS, we have to always work in the transparent mode.

    Thanks!

In transparent mode, the input signal also gets routed to the output, where it goes through an output buffer, which limits the bandwidth to about 50 MHz, but only for the output. The effective bandwidth to the sampling cells is not changed. Please note however that the 950 MHz are for the "chip only". We measured this by keeping the input amplitude from a function generator constant at the input pin of the chip (measured with a high speed oscilloscope). Since each signal source has a non-zero impedance, the signal tends to "shrink" at high bandwidth, and we had to adjust the level of the function generator to keep the amplitude constant at high frequencies. If you do a realistic input stage with the THS4508 for example, the achievable bandwidth will be around 800 MHz.