menzel f9ff89dc73
CI for csaxs_bec / test (push) Successful in 1m43s
fix(cont_grid): apply the premove along the direction of travel
The premove exists so the fast axis is already at speed when it reaches
the first point and still moving past the last one. It was applied with
a fixed sign:

    self.fast_start -= premove_distance
    self.fast_end   += premove_distance

which only lengthens an ascending line. On a descending one both ends
move inward instead: the stage starts past the first point and stops
before the last, with no run-up at either end, while frames_per_trigger
-- computed earlier from the original range -- still expects the full
travel, so the tail of the burst fires into a stage that has already
arrived. When the premove exceeds half the range the two ends cross over
and the line runs backwards; the test fixture's premove is 10.0 against
a range of 2.0, so that is the case it covers.

Latent rather than live: fast_axis_always_in_pos_dir defaults to True
and normalises a descending request to an ascending line before any of
this runs, so the wrong sign is only reachable when a caller passes the
flag as False. The flag is a documented scan argument, so the path is
real -- but no scan taken at the default has ever gone through it.

Also pins the normalisation itself. It is worth a test of its own
because it means a scan file records fast_start > fast_end while the
stage ran the other way, which is a trap when reading data back: the
first point of a line is at the numerically *lower* end regardless of
what the request said.
2026-08-25 21:38:50 +02:00
2026-08-19 12:03:18 +02:00
2025-05-24 11:37:51 +02:00

cSAXS BEC

cSAXS specific plugins and configs for BEC This document guides you through the procedure to spin up BEC at the beamline for a new experiment (e-account). You might want to run cSAXS copy scripts before in case you want to have the former data structure to be preserved.

Overview

  • Clone cSAXS BEC repository into e-account (e.g. into ~/Data10/software/.)
  • Start Epics iocs
  • Start BEC, BEC server and load/modify the device config with relevant hardware
  • BEC commands

Clone cSAXS BEC repository

Clone the current cSAXS BEC repository from GIT into the new e-account. Create directory

mkdir ~/Data10/software
cd ~/Data10/software

Clone repository

git clone https://gitlab.psi.ch/bec/csaxs_bec.git

Start epics iocs

You can start up the iocs while the ./setup_bec.sh script is running. Be aware though that the scripts requires you to interact with it.

DelayGenerator

Open a new tab in a terminal in comp1/comp2 or cons1 and follow the commands below:

ssh gac-x12sa@localhost
cd ~/delaygen
iocsh -7.0.6 startup.script

Be aware -7.0.6 is referring to the current epics version and might change in future (SLS 2.0). To start the epics panel (only if needed), run in a new shell

caqtdm -noMsg -macro P=delaygen:,R=DG1: srsDG645.ui

More notes on usages and cabelling of DDGs. Currently 3 generators are used:

  • DDG1 for detectors (EXT Enable from SGalil stages, T0 to DDG2, AB for eiger, CD for Falcon, EF for Pilatus_2)
  • DDG2 for mcs card (ext. enable from DDG1, AB to mcs card)
  • DDG3 for fast shutter and mcs enable (AB short pulse to enable MCS (needed!!), CD to keep FSH open )

Eiger

Open a new tab in a terminal in comp1/comp2 or cons1 and follow the commands below:

ssh gac-x12sa@localhost
cd ~/Software/Eiger/
./launch_ioc

A live view of status and images for std_daq can be found here xbl-daq-29:5000.

Pilatus_2

First, start the cam server. Connect to the computer and follow the instructions printed after connecting:

ssh det@x12sa-pd-2 (Pilatus2)

The cam server will open, wait until you see **. Nex step, open a new tab in a terminal in comp1/comp2 or cons1 and follow the commands below:

ssh gac-x12sa@localhost
cd ~/Software/Pilatus300K/
./launch_epics

FalconX1

Open a new tab in a terminal in comp1/comp2 or cons1 (logged in as the current e-account) and follow the commands:

ssh x12sa-cons-01
cd /ioc/X12SA-PC-FALCONX1/
iocsh -7.0.6 startup.script

Be aware -7.0.6 is referring to the current epics version and might change in future (SLS 2.0)

Start BEC, BEC server and load device config

Step 1 needs to have finished for continuing with these steps. What remains now is to start the bec server. Connect to pc15543 and open a new terminal to run:

cd ~/Data10/software
source bec_venv/bin/activate
bec-server start
tmux attach -t bec

Open another teminal on pc15543 and start BEC:

cd ~/Data10/software
source bec_venv/bin/activate
bec

Note: In case there is a warning after starting BEC that it was not able to import scilog, you will have to pip install scilog in the bec_venv to be able to send printouts to scilog from the command line. Within a new terminal:

cd ~/Data10/software
source bec_venv/bin/activate
pip install scilog

Device config from csaxs-bec plugins

bec.config.update_session_with_file('/sls/X12SA/data/e20639/Data10/software/csaxs-bec/bec_plugins/configs/bec_device_config_sastt.yaml')
bec.config.save_current_session('~/Data10/software/current_config.yaml')

The second command is helpful if you adjust limits of motors, which will then be stored in the config and loaded if a reload of the configuration is needed.

BEC commands

A number of commands that are useful:

To move devices that are added in the config:

umv(dev.samx, 0) #absolute
umvr(dev.samx, 0) #relative
dev.samx.wm #print motor position and limits
dev.samx.limits = [low_limit, high_limit] # To set limits, note, same lower and higher limit, e.g. [0, 0] means no limits!!

Scans:

scans.acquire(exp_time = 0.5, frames_per_trigger=10, readout_time=3e-3) # equivalent to a loopscan 30 0.5
scans.line_scan(dev.samx, -1, 1, steps=20, exp_time=0.5, readout_time=3e-3, relative=True) # optional, add frames_per_trigger =10 for burst acquisition at each step
#Scan 2 motors in a step scan at the same time
scans.line_scan(dev.samx, -1, 1, dev.samy, -1, 1, steps=20, exp_time=0.5, readout_time =3e-3, relative=True) # step scan with 20 steps, again frames_per_trigger can be added for burst at each point
scans.sgalil_grid(start_y = , end_y = , interval_y = , start_x=, end_x=, interval_x =, exp_time=0.5, readout_time=3e-3, relative=True)
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