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| OSCILLATION.MAC | ||||||
| [ source code | installed at | configured at ] | ||||||
| See other macros in category: Scans | ||||||
Description:
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Documentation:
Use for standard single crystal X-ray diffraction data collection. The sample is exposed to the X-ray beam rotating with constant speed on a goniometer spindle while the diffraction pattern is recorded by an area detector (X-ray image intensifier/CCD). Because of the short exposure times at a synchtrotron (down to 0.1 s) the timing of X-ray shutter and rotation has to be done with care. The stepper motor pulses for the spindle rotation are monitored by counting module (VME Counter-Timer 6). This card generates a gate pulse opening and closing an electromagnetical fast X-ray shutter at the begin and end of the oscillation range. Acceleration and deceleration ramp are taken into account as well. On ID30 the VCT6 card has to be connected the following way: From the Mtheta motor the "TOPMOT" signal MUST be connected to both STRT 2! (not 1) and equally IN 2! (not 1). This is in the little rectangle on the front of the Vct6:
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| O ......... O |<-
| 1 . STRT .. 2 | |
| O ......... O | |--- connect both to TOPMOT mth
| 1 . STOP .. 2 | |
| O ......... O | |
| 1 GATE-IN . 2 | |
| O ......... O |<-
| 1 . IN .... 2 |
| O ......... O | Sorry all the dots are just to
| 1 GATE-OUT. 2 | make the picture look correct.
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You must also connect the fast shutter cable to the Vct6 plug 1 in the lower
rectangle at the bottom of the card.
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| ............. |
| ... O. 1 .. |< ---- fast shutter
| ............. |
| ... O. 2 .. |
| ............. |
| ... O. 3 .. |
| ............. |
| ... O. 4 .. |
| ............. |
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Dark current substraction is done online automatically. Every time you
change the exposure time a new dark current image will be read out to be
substracted from the image data.
SETUP Please make sure the input 1 of the VCT6 card are configured for TTL level (low = 0V, high = +5V). Open the file ~dserver/dbase/res/ID30/id301Vct6_1.res und check whether the following lines are present: ID30/vct301_1/1/GateLevel: TTL id30/vct301_1/1/InputLevel: TTLRestart the "Vct6" device server: opid30@megabar> telnet id301 User name?: root rt id301[1]: procs ! grep Vct 85 0 0.0 128 92.00k 0 s 0.21 127:00 Vct6 <>>>nil id301[2]: os9kill -2 85 id301[3]: ID301Vct6_0.startupI hope a future release of the VCT6 device server will provide a device server call for the input level so this operation can be included in the SPEC macro. | ||||||
Macros:
Usage: oscillation %MDESC% (or "collect") a menu driven routine to take complete data sets collect Usage: collect %MDESC% (same as "oscillation") oscillsetup Usage: oscillsetup [gonio] [detector] [shutter] [vct6] [gate] [trigger] [timer] [ccd] Global setup. Define all beeamline dependent parameters. Put this line in your beamline's setup file. oscillation_debug Usage: oscillation_debug [on|off] use this macro to obtain more detailed information what is happening in case off problems. Informational messages will be written line by line rather than on the status line on the botton of the screen erasing each other. MM_mar_imagepar Usage: MM_mar_imagepar(__ccd_u, start_angle, stop_angle, exp_time, range, n_phi_osc, d_s_dist, \ wavelength) Set image parameters, detector distance and wavelength | ||||||
| Internal Macros: | ||||||
Usage: oscillation_data_collection_menu setup all needed parameters to acquire a full data set, such as angular step, rotation range, exposure time and filenames oscillation_setup Usage: oscillation_setup data_set Usage: data_set (arg[,param]) print inforation about the number of images in the data set warn if files may be overwritten data_set_check Usage: data_set_check used by the "data_set()" macro data_file Usage: data_file (image_number) %MDESC% Return full absolute path name for image oscillation_initialize Usage: oscillation_initialize Set the user configurable parameters to some resoable defaults when the "oscillation" macro is invoked the first time. The parameters wont be reinitialized in subsequent calls Since they are stored on global variables, which keep their values from one SPEC session to the next. Only if the parameters seem to be cleared, because of a SPEC restart with the -f (from fresh) option or a crash, they will be reloaded from the ASCII file, where the "save_oscillation_parameters" macro saves them. save_oscillation_parameters Usage: save_oscillation_parameters Save all user configurable parameters into an ASCII file so they are not not lost when SPEC is restarted with the -f (from fresh) option, clearing all global variables. The parameters are hold in 2 global arrays, OSCILL and OSC_DATA. oscillation_data_collection Usage: oscillation_data_collection Acquire a complete data set. parameters such as angular step, rotation range, exposure time and filenames are passed in the global array "OSCILL" single_oscillation_image Usage: single_oscillation_image %MDESC% useful for sample screening and optimizing the exposure time rotate_spindle_to Usage: rotate_spindle_to <new_position> manages absolute motions of the goniometer axis. rotate_spindle_by Usage: rotate_spindle_by <amplitude> manages relative motions of the goniometer axis. oscillation_log Usage: oscillation_log filename angle Append data collection information to the log file as defined by OSC_DATA ["log_file"]. data_collection_info Usage: data_collection_info Display progres info at bottom of screen This macro allows subroutine to display messages keeping a clear screen layout open_safety_shutter Usage: open_safety_shutter open_safety_shutter replaces "shopen" macro, which causes problems because it messes up the sceen by unnessary messages and does not wait until the shutter is actually open. close_safety_shutter Usage: close_safety_shutter take_oscillation_image Usage: take_oscillation_image [range [exposure-time [no-of-oscillations] ] ] Takes a single oscillation image oscillating by <range> degrees in positive direction from the current position. <exposure-time> is the total accumulated exposure time the X-ray shutter is openend. The actual time used may be longer. take_still_image Usage: take_still_image %MDESC% Used instead of "take_oscillation_image" when the oscillation range is set to 0. If the spindle axis is not rotated the synchronziation of the X-ray shutter must be done in a different way. check_oscillation_parameters Usage: check_oscillation_parameters There are hardware constraints which limit the allowed combinations of oscillation range, exposure time and number of oscillations. This routine will try to find the closest possible set of parameters to a given set first modifying the number of oscillations if the rotation speed is too low or too high, then exposure time, but leaving constant the rotation angle. The minimum stepping speed of the gonio-rotation is 15 steps/s ,as for all stepper motors controlled by an ESRF VPAP card. In principle there is no minimum rate for a stepping motor, but unfortunatly the value of 15 Hz is hard coded in the CY550 microcontroller the VPAP is based on. The maximum stpping is taken as the one preconfigured by SPEC at startup. You may increase it using "config" if you feel confident about this. The parameters oscillation range, exposure time and number of oscillations are passed and returned in a global array called "OSCILL". oscillation_cleanup Usage: oscillation_cleanup() This Macro is executed when an oscillation image is cancelled by Control-C. It closes the ms shutter, sets the original values for the speed of the rotation motor gonio and rotates it back to the starting position. oscillation_restore Usage: oscillation_restore() restore default settings of the VCT6 and of the spindle motor oscillation_detector_setup Usage: oscillation_detector_setup oscillation_prepare_detector Usage: oscillation_prepare_detector oscillation_readout_detector Usage: oscillation_readout_detector save_oscillation_image Usage: save_oscillation_image(filename) ccd Usage: ccd (parameter,value) General setup for CCD detector (Princeton or FRELON) prepare_ccd Usage: prepare_ccd() Configure the detector and start the exposure. Works for both FRELON and Princeton CCD. readout_ccd Usage: readout_ccd() Stops the exposure and waits for the data transfer to the workstation's memory to finish. The image content will be in the global array image_data. The image is not save as a file. You have to call "save_ccd_image" to do this. Works for both FRELON and Princeton CCD. save_ccd_image Usage: save_ccd_image(filename) oscillation_bruker_setup Usage: oscillation_bruker_setup() Setup menu prepare_bruker Usage: prepare_bruker() Configure the Bruker CCD detector and start the exposure. readout_bruker Usage: readout_bruker() starts the acquisition in the Bruker detector PC. oscillation_mar_setup Usage: oscillation_mar_setup() Setup menu prepare_mar Usage: prepare_mar() Configure the MAR image plate scanner and start the exposure. readout_mar Usage: readout_mar() Scans and erase the MAR IP scanner fsds_osc_setup Usage: fsds_osc_setup() Setup menu fsds_osc_prepare Usage: fsds_osc_prepare() fsds_osc_readout Usage: fsds_osc_readout() fsds_osc_save Usage: fsds_osc_save(filename) ceil Usage: ceil(x) round up to the next larger or equal integer, as opposed to int() which rounds down round Usage: round(x) round up to the next integer, as opposed to int() which rounds down info Usage: info <message> ... "info" used to display informational messages which can be helpful for debugging. The reason not simply to use "print" is to the collect macro can redirect or supress these messages by redefining "info" notice Usage: notice(message) key Usage: key ([prompt]) Utility for keybard input in single character no-echo mode. The prompt string is optional. edit Usage: edit <variable> [<max length>] editline Usage: editline (template-text[,max_length]) Prompts the user for test input, providing a template, like SPEC's built-in getval(), but you do not have to retype it but can modify it using the cursor keys. Note: The cursor keys work only on VT100 terminal emulators, "xterm" and "dtterm" are compatible with VT100, however "hpterm" is not. update_line Usage: update_line used by "editline" scroll Usage: scroll used by "editline". Scroll text so cursor is within bounds escape_sequence Usage: escape_sequence used by "editline". Decode VT100 escape sequences generated by the cursor keys cursor_left Usage: cursor_left used by "editline" cursor_right Usage: cursor_right used by "editline" insert_char Usage: insert_char(c) used by "editline" delete_char Usage: delete_char used by "editline" save_array Usage: save_array <array> Useful for save global variables across a "spec -f". Writes the contents of all members of an array to an ASCII file, so they can be reloaded later by the "restore_array" macro. The file is in the directory ~specadm/local/userconf and has the same name as the array (no extension). restore_array Usage: restore_array <array> Loads back saved values from an ASCII file from a previous "save_array" call. sign Usage: sign (x) returns 1 if x>0 -1 if x<0 0 if x=0 tail Usage: tail (string,n) returns the last n characters of a string. If the sting length is less the n then the full string is returned oscillation_prepare_diode Usage: oscillation_prepare_diode %MDESC% Beam intensity measurement macro, called once before the exposure (ie before the set of half-oscillations). oscillation_read_diode Usage: oscillation_read_diode %MDESC% Beam intensity measurement macro, called during the exposure after each half-oscillation. oscillation_log_diode Usage: oscillation_log_diode %MDESC% Beam intensity measurement macro, called during the exposure after each half-oscillation. enter_speed_parameter Usage: enter_speed_parameter %MDESC% Enter the speed parameter with some value check. calculate_speed Usage: calculate_speed %MDESC% Calculate the motor speed according to the range parameter and the motor parameters. | ||||||
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