Qualifiers for General Scans

This is the list of qualifiers that apply to all general scan modes:

 /auto_beam
A fast scan option which allows you to recover from beam losses automatically. Fast scans are described in section 8.1.11.

If ONLINE detects that the count rate in scan_c1, which is gated by scan_timer, falls below scan_min_c1, it enters the waiting-for-the-beam function. Mind that scan_min_c1 is the minimal rate per second. The current count rate of scan_c1 is corrected by the sample time before it is compared to scan_min_c1.

The waiting-for-the-beam function measures the signal once every two seconds. If it detects that it is above scan_min_c1, it sleeps for time_heatup seconds (default 30) and returns to the general scan procedure.

If /mostab was supplied on the command line, the v0 is resetted (see below).

 /cont*inuous
Selects the on-the-fly scanning mode. See section 8.1.5.

 /di*splay
The display routine is automatically called after every point or /update=n_up points. The purpose of this option is to save CPU time. DISPLAY can also be called in during_type_scan or it can be done during wait_for_timer() (see section 8.1.11). In case of fast scans, there is an automatic display unless it is suppressed by the /nodisplay qualifier.

 /exec*ute
A scan is executed without passing control to the menu driver. The scan parameters remain as they are unless they are overwritten by qualifiers, like /_start, etc.

An example of performing scans in the /exec mode can be found in section 15.8.

If scan_name exists already, it is replaced without asking for confirmation.

 /generic_macro_name=val (alias: /gmn)
Selects the macros $<$~.prog$>$before_VAL_scan.pl, etc.

 /generic_macro_name_gra=val (alias: /gmng)
Selects the macros $<$~.prog$>$before_VAL_scan.gra, etc.

 /most*ab
Stabilizes the monochromatic flux during scans.

ONLINE> scan/mostab=(motor_name, range, ratio)...

Requiers the fast scan mode. The counters Scan_c1 and scan_c2 are mandatory. They measure the white and monochromatic intensity.

At the beginning of a scan, c2/c1 is measured and stored in v0. The ratio c2/c1 is measured for every stop -> vi. If vi/v0 is less than ratio (from the command line), the intensity is optimized by moving motor_name in the range [current position - range/2, current position + range/2]. This is done by the command cali/center....

motor_name is re-calibrated and v0 is reset to the current c2/c1.

 /noa*lpha
/notext
Suppresses the output to the alphanumeric screen during scans. This option is useful, if the user prepared his own output in during_type_scan.

 /nocls
Suppresses the clear-graphics-screen sequence which is normally executed before the scan begins. This switch can be useful together with the /exec flag, if the scan routine is called from a command file or user code.

 /normalize_counts
The counter readings are offset corrected and normalized to 1s sample time, like for EXAFS scans.

 /np=npoints
The size of scan_name. By default it is calculated from the scan range and the step width. This qualifier is needed only, if a /variable or /continuous switch has been supplied.

 /opt_der
An option for repeated (EXAFS) scans. For r=1, there will be an auto-display, but not for r>1. After_exafs_scan.gra takes care of this.

 /preset
Fast scan option: Scan_timer is used as a preset counter (Borer 1008, DGG only). The sample_time parameter is is used to load the register.

ONLINE determines the sample time, which is needed for the offset corrections of the counter readings, with the help of the computer clock.

If the elapsed wait time exceeds wait_time_preset_max, the wait state is terminated and ONLINE waits for time_heatup seconds (default 30) before it re-measures the last point. This procedure has been implemented for a recovery after injections.

 /raw_display
Selects the raw display mode, i.e.: Each signal is displayed in a separate viewport. To be used, for example, in /exafs scans, if the default exafs screen is not appropriate.

 /time_check
Directs ONLINE to display where the time is spent:

move	The time used for motor movements, including backlashes and settle time. This contribution can be reduced by increasing the slew rate and the acceleration. Try to avoid backlashes during scans.
display	The time used for display operations. The wft_command is not included. The contribution can be reduced by increasing the /update qualifier.
sample	The total sample time.
rest	The time used for read-out, wft_command, etc.
during	Time used in during_type_scan.gra. Try to execute fast scans, which means that this command file is empty. Mind that ONLINE has to recalculate the internal data addresses, if commands were executed in during_type_scan.gra.

 /up*date_cycle = n_up
The menu screen is updated only after each n_up$th$ point. This is also true for the graphical output, if the /display qualifier has been supplied.

 /var*iable
Selects the variable step width option. The step width can be changed by a symbol assignment in before_type_scan.gra or in during_type_scan.gra (delta = new_value).

 /_auto_return=value
/_comment=string
/_delta=value
/_np_scan=value
/_range=value
/_repeats=value
/_sample_time=value
/_scan_name=string
/_scan_par=value
/_ssa=value
/_ssa_nbs=0_or_1 (if 1, selects 'no-background-subtraction')
/_start=value
/_stop=value
/_wait_time=value
These qualifiers provide initial values for the scan parameters. They can be changed in the menu. The description of the scan parameters is given in the next section. If the default of a parameter is not set by a qualifier, ONLINE searches for symbols which provide the defaults. The symbol names are of the kind parameter_name_type, e.g.: sample_time_energy, start_dummy or stop_mot25. ONLINE creates these symbols when the menu routine exits, but they may also be created by the user.