BNMR: Scripts

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Introduction

A number of important scripts are used in the bnmr and bnqr experiments. Some of the most important are described here. Unless otherwise noted, the scripts described here can be found in directory ~/online/<beamline>/bin.

Another important group of scripts are the perlscripts found in directory ~/online/<beamline>/perl. These are described under BNMR: Perlscripts.

.cshrc

This important script in $HOME is the c-shell script executed on log in. This sets up the path, the aliases and environment variables required for running the DAQ system. This file is shared by all the machines in the NIS cluster with isdaq00 as master. This includes isdaq01, isdaq06, lxbnmr, lxbnqr. This script therefore checks the $HOST environment variable before setting up the DAQ system. See BNMR: Experimental Setup for details.

Scripts to restart MIDAS clients

A number of scripts are provided to start or restart the MIDAS clients needed for the data acquisition system. The most important of these is start-all which starts any missing clients. Scripts are also provided to start individual clients. These scripts are usually accessed from the Programs page when the user presses the restart button.

A script kill-all is provided to shut down all the clients.

start-all

start-all is an alias to the script start-all-daq-bn[mq]r (see Nomenclature). This script is run by the experimenter to start all the MIDAS clients needed for the DAQ system. It checks to see if each client is already running, and if not, starts it either by calling another script, or directly. It can be run at any time during the run to restart missing clients.

Environment variable EXPERIM_DIR must be defined (in .cshrc). This script calls #check-host-bnmr or check-host-bnqr.

kill-all

kill-all is an alias to the script kill-all. This script kills all DAQ related clients. When there is some problem with the DAQ that cannot be otherwise resolved, users often do a kill-all followed by a start-all to ensure a clean restart.

Recently (June 2016) an extra feature has been added to the script kill-all. This is the execution of the file init_odb.com. This file is an odbedit command file containing a list of ODB keys to initialize to their default state.

restart_frontend

The script restart_frontend is run when the BNMR: Programs page button restart is pressed. This script is run on the host computer. It opens an ssh session on the VMIC and runs the script start_frontend.

start_frontend

The script start_frontend must be run on the VMIC (not the host computer). It is may be run directly, but is usually called by the script restart_frontend. It starts the frontend program for bnmr or bnqr experiment under the screen program (see show-windows).

start_mheader

The script start_mheader is run when the BNMR: Programs page button restart for client mheader is pressed. This script is run on the host computer. Because mheader is or can be run under the screen program (see show-windows).

start_mdarc

The script start_mdarc is run when the BNMR: Programs page button restart for client mdarc is pressed. This script is run on the host computer. This script restarts the client mdarc under the screen program (see show-windows).

Script to show screen program windows

show-windows

show-windows is an alias to the script show-windows. This script attaches to and displays (in an xterm, if possible) one or all midas clients that were started and managed under the screen program. This includes clients mdarc,mheader and the frontend (client name febn[mq]r_vmic - see Nomenclature).

The advantage of the screen program is that the terminal does not disappear when the client fails. Also it can be accessed from another terminal, and killing the window does not kill the client.

Previously each of these clients was started in an xterm by start-all, so that progress could be monitored, and any errors :displayed. The xterms appeared on the screen where start-all was executed, and were inaccessible to any other terminal. If the

client failed, the xterm promptly disappeared, so only the error messages sent to the MIDAS logger could be read.

• To display all windows, give no argument, or the word "all".
• To display a specific window, give the parameter in Table 1 :

Table 1 show-windows parameters

Command	Parameter	Action
show-windows		to show all windows
show-windows	all
show-windows	vmic	to show frontend window
show-windows	frontend
show-windows	mdarc	to show mdarc window
show-windows	mheader	to show mheader window

Scripts to check environment variables

These scripts are often included in other scripts to check that important environment variables are set up and the script is being run on the correct computer (i.e. host computer or VMIC)

check-host-bnmr or check-host-bnqr

The appropriate script check-host-bn[mq]r (see Nomenclature) is called by #start-all.

It checks that the following environment variables are defined:

DAQ_HOST MIDASSYS MIDAS_EXPTAB MIDAS_EXPT_NAME DAQ_HOST MSERVER_PORT BEAMLINE

It further checks that the user is logged onto the correct computer for DAQ (i.e. HOST matches DAQ_HOST) and that MIDAS_EXPT_NAME and BEAMLINE match the username ( bnmr or bnqr).

check-host-vmic

The script check-host-vmic checks that the script is being run on the VMIC rather than the MIDAS host machine (i.e. HOST matches VMIC_HOST) It is called by start-frontend.

Scripts run at start or end of run

at_start_run.pl

The script at_start_run.pl is executed at the start of every run by the MIDAS system (see #NOTE below). Depending on the supplied parameter, it checks the experiment can access CAMP or EPICS logged variables or both.

When checking access to the CAMP slow control system, it calls the script do_camp.csh to check that the CAMP logged variables (including automatic logged variables) can be accessed, and zeroes the CAMP statistics. Similarly, when checking EPICS access, it also checks that the EPICS logged variables (if enabled) exist and can be accessed. If an error occurs, it sets alarms in the ODB to inform the experimenters by means of an alarm banner on the custom status page.

NOTE

This script performs two functions - it is called at start of run, and hence is located with the other scripts in ~/online/<beamline>/bin. It is also a customscript which is called from the bnmr and bnqr main status page when the custom buttons ResetCampLog or ResetEpicsLog are pressed, in order to reinitialize CAMP or EPICS logging. See BNMR: Perlscripts#at_start_run.pl.

do_camp.csh

The script do_camp.csh is called from script at_start_run.pl, and performs various checks on the CAMP parameters,

• checks the automatic header variables, making sure they are set as logging variables within CAMP.
• ensures all logging variables are being polled.
• zeroes the statistics on *ALL* camp variables.
• for type-1 experiments, retrieves the list of logged variables from Camp and copies the list into the ODB.

at_end_run.csh

The script at_end_run.csh is executed at the end of every run (see #NOTE). This script runs a script elog_every_run.csh, and calls a script to clear some alarm conditions.

elog_every_run.csh

This script reads the /Experiment/Edit on start parameters (i.e. the parameters entered by the experimenter on starting a run), other ODB parameters including the Experimental (PPG) Mode of the run and whether it is run in dual or single channel mode, reads the statistics of the CAMP logged devices, and sends them all to the appropriate elog bnmr or bnqr. Automatic elog entries are identified in the Elog by the Type ("Automatic Elog"). The System parameter is set to the PPG Mode of the run.

NOTE

The MIDAS system provides a means whereby users' scripts can be automatically executed at the start or end of the run, by means of keys in the ODB /programs tree. The key Execute on start run contains the name and path of a script to be executed at the start of every run, and the key Execute on stop run contains the name and path of a script to be executed at the end of every run. For example,

[local:bnqr:Stopped]/>ls "/programs/Execute on start run"
   Execute on start run            /home/bnqr/online/bnqr/bin/at_start_run.pl /home/bnqr/online/perl bnqr >/home/bnqr/tmp/at_start_run_pl.log
[local:bnqr:Stopped]/>ls "/programs/Execute on stop run" 
   Execute on stop run             /home/bnqr/online/bnqr/bin/at_end_run.csh

For more information see MIDAS /Programs ODB tree.