Acquisition chain¶

Screenshot

Used by a Scan object, the AcquisitionChain object is like a tree describing the relations between masters and slaves in term of triggering. To define such a relation, sub-objects inherited from AcquisitionMaster or AcquisitionSlave are inserted into the chain.

Screenshot

The tree is built using add() method with the master and a slave passed as arguments.

Note

An AcquisitionChain can only be run once by a scan.
It’s sometimes needed to control the state of devices like shutter, multiplexer, or detector cover. Those devices should be controlled with Preset objects.

Add acquisition objects example¶

2 points loopscan with 1 counter:

from bliss.scanning import chain
from bliss.scanning.acquisition.timer import SoftwareTimerMaster
from bliss.scanning.acquisition.counter import SamplingCounterAcquisitionSlave
acq_chain = chain.AcquisitionChain()
timer = SoftwareTimerMaster(1, npoints=2)
counter_device = SamplingCounterAcquisitionSlave(diode, count_time=1, npoints=2)
acq_chain.add(timer, counter_device)
print(acq_chain._tree)

Out [4]:
acquisition chain
└── timer
    └── simulation_diode_sampling_controller

To execute the loopscan:

from bliss.scanning.scan import Scan
s = Scan(acq_chain,name='simple loop',scan_info={},save=False)
s.run()
s.get_data()

Out [12]: {'elapsed_time': array([0. , 1.0063]),
           'diode': array([11.59349, -6.2747])}

To transform the loopscan into an ascan:

from bliss.scanning.acquisition.motor import LinearStepTriggerMaster
motor_master = LinearStepTriggerMaster(2,robz,0,1)
acq_chain.add(motor_master,timer)
print(acq_chain._tree)

Out [12]:
acquisition chain
└── axis
    └── timer
        └── simulation_diode_sampling_controller

Calling sequence¶

When the Scan iterates over the AcquisitionChain, AcquisitionMaster and AcquisitionSlave are called in a defined sequence.

For each iteration, the acquisition chain calls are:

wait_ready which should return when the device is ready to have an other trigger.
prepare device preparation.
start starts acquisition on device

All the calling functions of masters and slaves during a scan can be displayed using the bliss.scans logger.

DEMO [1]: s = loopscan(2,1,diode,diode2,run=False)
DEMO [2]: debugon('bliss.scans')
DEMO [3]: s.run()
DEBUG 29,288 Scan: Start timer.wait_ready
DEBUG 29,289 Scan: End timer.wait_ready Took 0.000449s
DEBUG 29,289 Scan: Start diode.wait_ready
DEBUG 29,289 Scan: Start simulation_diode_controller.wait_ready
DEBUG 29,290 Scan: End diode.wait_ready Took 0.000545s
DEBUG 29,290 Scan: End simulation_diode_controller.wait_ready Took 0.000495s

Scan 11 Wed Mar 06 24 2019 /tmp/scans/test_session/data.h5
                                 test_session user = seb
loopscan 2 1

           #         dt[s]         diode        diode2
DEBUG 29,314 Scan: Start simulation_diode_controller.prepare
DEBUG 29,314 Scan: End simulation_diode_controller.prepare Took 0.000120s
DEBUG 29,314 Scan: Start diode.prepare
DEBUG 29,314 Scan: End diode.prepare Took 0.000040s
DEBUG 29,314 Scan: Start timer.prepare
DEBUG 29,315 Scan: End timer.prepare Took 0.000033s
DEBUG 29,315 Scan: Start simulation_diode_controller.start
DEBUG 29,315 Scan: End simulation_diode_controller.start Took 0.000536s
DEBUG 29,315 Scan: Start diode.start
DEBUG 29,316 Scan: End diode.start Took 0.000395s
DEBUG 29,316 Scan: Start timer.start
DEBUG 29,316 Scan: Start timer.trigger_slaves
DEBUG 29,316 Scan: End timer.trigger_slaves Took 0.000090s
DEBUG 29,317 Scan: Start diode.trigger
DEBUG 29,317 Scan: End diode.trigger Took 0.000062s
DEBUG 29,317 Scan: Start simulation_diode_controller.trigger
DEBUG 29,317 Scan: End simulation_diode_controller.trigger Took 0.000037s
DEBUG 29,318 Scan: Start timer.wait_slaves
DEBUG 29,318 Scan: End timer.wait_slaves Took 0.000249s
DEBUG 30,319 Scan: End timer.start Took 1.002655s
DEBUG 30,320 Scan: Start timer.wait_ready
DEBUG 30,321 Scan: End timer.wait_ready Took 0.000566s
DEBUG 30,322 Scan: Start diode.wait_ready
DEBUG 30,322 Scan: Start simulation_diode_controller.wait_ready
DEBUG 30,323 Scan: End diode.wait_ready Took 0.001143s
DEBUG 30,323 Scan: End simulation_diode_controller.wait_ready Took 0.001143s
DEBUG 30,324 Scan: Start timer.prepare
DEBUG 30,325 Scan: End timer.prepare Took 0.000302s
DEBUG 30,326 Scan: Start timer.start
DEBUG 30,327 Scan: Start timer.trigger_slaves
DEBUG 30,327 Scan: End timer.trigger_slaves Took 0.000420s
DEBUG 30,328 Scan: Start diode.trigger
DEBUG 30,329 Scan: End diode.trigger Took 0.000344s
DEBUG 30,329 Scan: Start simulation_diode_controller.trigger
DEBUG 30,329 Scan: End simulation_diode_controller.trigger Took 0.000291s
DEBUG 30,332 Scan: Start timer.wait_slaves
DEBUG 30,334 Scan: End timer.wait_slaves Took 0.001394s
          0             0       3.52747      -2.57778
DEBUG 31,329 Scan: End timer.start Took 1.002674s
DEBUG 31,331 Scan: Start timer.wait_ready
DEBUG 31,331 Scan: End timer.wait_ready Took 0.000565s
DEBUG 31,332 Scan: Start diode.wait_ready
DEBUG 31,332 Scan: Start simulation_diode_controller.wait_ready
DEBUG 31,339 Scan: End simulation_diode_controller.wait_ready Took 0.006308s
DEBUG 31,339 Scan: End diode.wait_ready Took 0.007317s
DEBUG 31,340 Scan: Start timer.wait_slaves
DEBUG 31,340 Scan: End timer.wait_slaves Took 0.000504s
          1       1.01025      -1.74157       10.4382
DEBUG 31,349 Scan: Start timer.stop
DEBUG 31,350 Scan: End timer.stop Took 0.000574s
DEBUG 31,351 Scan: Start diode.stop
DEBUG 31,352 Scan: End diode.stop Took 0.000701s
DEBUG 31,352 Scan: Start simulation_diode_controller.stop
DEBUG 31,352 Scan: End simulation_diode_controller.stop Took 0.000295s
DEBUG 31,353 Scan: Start timer.wait_slaves
DEBUG 31,354 Scan: End timer.wait_slaves Took 0.000611s

Took 0:00:06.935785

Display the chain tree¶

A print() on the tree property of the acquisition chain object, displays the acquisition tree.

Example:

DEMO [1]: s = ascan(robz, 0, 1, 10, 0.1, diode2, diode3, run=False)
DEMO [2]: print(s.acq_chain.tree)
acquisition chain
└── axis
    └── timer
        └── simulation_diode_sampling_controller

Going further¶

To build more advanced acquisition chain, see the custom scans section.