The ApplicationCore-MicroDAQ package provides ApplicationCore modules for data acquisition.
It includes an abstract base class ChimeraTK::BaseDAQ, that can be used to implement different DAQ backends.
Currently two DAQ backends are implemented:
ChimeraTK::HDF5DAQ: HDF5 based DAQ that uses uncompressed HDF5 files.ChimeraTK::ROOTDAQ: ROOT based DAQ that uses compressed ROOT files.
The provided modules include configuration and status process variables. DAQ problems are indicated by the process variable DAQError.
In case of DAQ errors just disable and reenable the DAQ once.
The idea to use ROOT files instead of HDF5 files is to reduce the file size and improve the analysis performance, especially when working with many large files.
The envelope class MicroDAQ can used to include the DAQ into a server, while allowing to configure the daq via the server config file.
In the config file, the following variables are required:
- MicroDAQ/enable (int32): boolean flag whether the MicroDAQ system is enabled or not
- MicroDAQ/outputFormat (string): format of the output data, either "hdf5" or "root"
- MicroDAQ/decimationFactor (uint32): decimation factor applied to large arrays (above decimationThreshold)
- MicroDAQ/decimationThreshold (uint32): array size threshold above which the decimationFactor is applied
If MicroDAQ/enable == 0, all other variables can be omitted.
In order to use the envelope class the MicroDAQ class needs to be defined after the ChimeraTK::ConfigReader in the server application. The MicroDAQ constructor takes an inputTag, which is used to identify
variables of other modules that should be connected to the DAQ module. The tags passed in the constructor of MicroDAQ will be added to all process variables of the
daq.
It is possible to connect DeviceModules to the DAQ. This can be done by calling addDeviceModule in the constructor of your application.
It is currently not possible to connect variables of device modules automatically to the DAQ module, because it requires a certain tag to identify the daq variables and currently
it is not possible to add tags to the DeviceModule.
The data stored in the *.h5 files is always of type float. In case of the ROOT backend the ChimerTK data types are properly mapped to ROOT data types, which further reduces the file size and improves analysis performance.
It might happen that some includes are not found by ROOT. In that case setting the environment variable ROOT_INCLUDE_PATH=/usr/ might help, in case an error is saying that include/data_types.h is not found.