Common code for MID and MCH

For the moment the only commonality stems from the DCS to CCDB part, as both subsystems only transmit DCS datapoints to CCDB, without any particular treatment. So we use almost the same source code, but generate separate executables, e.g. to ease the integration with dcs-proxy-based workflows.

Note that MCH transmit both the HV and LV values to CCDB, while MID only transmit HV values.

DCS to CCDB

To test the DCS to CCDB route you can use the following 3 parts workflow pipeline :

o2-calibration-mch-dcs-sim-workflow --max-timeframes 600 --max-cycles-no-full-map 10 -b | \
o2-calibration-mch-dcs-processor-workflow --hv-max-size 0 --hv-max-duration 300 --lv-max-size 0 --lv-max-duration 300 -b | \
o2-calibration-ccdb-populator-workflow --ccdb-path="http://localhost:6464" -b

o2-calibration-mid-dcs-sim-workflow --max-timeframes 600 --max-cycles-no-full-map 10 -b | \
o2-calibration-mid-dcs-processor-workflow --hv-max-size 0 --hv-max-duration 300 -b | \
o2-calibration-ccdb-populator-workflow --ccdb-path="http://localhost:6464" -b

Note that the only difference (besides the mid vs mch naming) is the set of options of the processor device (handling just hv for mid and hv+lv for mch).

o2-calibration-[mch|mid]-dcs-sim-worfklow is just generating fake random MCH or MID DCS data points
o2-calibration-[mch|mid]-dcs-processor-workflow gathers the received data points into a container object
o2-calibration-ccdb-populator-workflow uploads the container object to the CCDB (in this example a local dev ccdb).

The container object that groups the datapoints is considered ready to be shipped either when the data points span a long enough duration (see the --xxx-max-duration option(s) of the o2-calibration-[mch|mid]-dcs-processor-workflow) or is big enough (see the --xxx-max-size option(s)).

MCH DCS Data Points

HV

The MCH high voltage (HV) system is composed of 188 channels :

48 channels for stations 1 and 2 (3 HV channel per quadrant x 16 quadrants)
140 channels for stations 3, 4, 5 (1 HV channel per slat x 140 slats)

LV

The MCH low voltage (LV) system is composed of 328 channels :

216 channels (108 x 2 different voltage values) to power up the front-end electronics (dualsampas)
112 channels to power up the readout crates hosting the solar (readout) cards

MID DCS Data Points

HV

The MID high voltage (HV) system is composed of 72 channels, one channel per RPC.

CCDB quick check

Besides the web browsing of the CCDB, another quick check can be performed with the o2-[mch|mid]-dcs-ccdb program to dump the DCS datapoints (hv, lv, or both) or the datapoint config valid at a given timestamp.

o2-mch-dcs-ccdb --help
o2-mch-dcs-ccdb --ccdb http://localhost:6464 --query hv --query lv --query dpconf
o2-mid-dcs-ccdb --ccdb http://localhost:6464 --query hv --query dpconf

The same programs can be used to upload to CCDB the DCS data point configuration for the dcs-proxy :

o2-mch-dcs-ccdb --put-datapoint-config --ccdb http://localhost:8080

o2-mid-dcs-ccdb --put-datapoint-config --ccdb http://localhost:8080

Default CCDB object

The default objects in the CCDB can be produced as follow:

MCH/Calib/HV

o2-mch-dcs-ccdb --ccdb http://localhost:8080 --upload-default-values -t 1546300800000

One DCS data point is created for each channel with the timestamp provided with the -t option. The validity range of the object is set from 1 to 9999999999999 and its creation time is set to 1.

MID/Calib/HV

o2-mid-dcs-ccdb --ccdb http://localhost:8080 --upload-default-values -t 1662532507890

The timestamp represent the last time of validity. This is needed because the default object was added after the CCDB feeding was active and would therefore take over the old measured values.