Hello,
I am using a CAEN v1720 to digitise signal coming from 5 PMTs and I need to extend the read-
out window to 1ms.
Given the sampling frequency of 250 MHz, each event would consist of about 4.78 MB
Accordingly to the documentation I found in:
https://midas.triumf.ca/MidasWiki/index.php/Event_Buffer
- I modified the value of ODB /Experiment/MAX_EVENT_SIZE to 8 MB (I overestimated it in case
I will readout all 8 channels of the v1720)
- I modified the ODB key /Experiment/Buffer Sizes/SYSTEM to 512 MB (which allow to contain
about 100 events in the buffer)
The max_event_size in the frontend source code is set to 32 MB while the event_buffer size is
200 times the max_event_size. So I did not modify those values.
When I start a new run, the MIDAS crash and the ODB gets corrupted:
$ odbedit
[ODBEdit,ERROR] [odb.c:1134:db_open_database,ERROR] Different database format: Shared
memory is 262148000, program is 3
[ODBEdit,ERROR] [midas.c:2157:cm_connect_experiment1,ERROR] cannot open database
Unexpected error #326
Do you have any idea of what might be the problem?
The same thing happen if I reduce the buffer size to 128 MB.
The computer running MIDAS has 2 Quad CPU @ 2.83GHz and 4 GB RAM.
Thank you in advance for any help!
Alberto |