CAD4 List Commands

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Next: Crystal orientation routines

NONIUS CAD4/MACH3
User manual

21 December 2000

CAD4 List Commands

Introduction
The reflection list
Command format of reflection list operations
List entry operations
Status code operations

Introduction

The list group consists of a set of commands allowing the operator to operate on the list of reflections (the CRYSTAL file). The CRYSTAL file may contain data (setting angles, intensity and control parameters) of 25 reflections and it is used in the orientation and data-collection stages.

List group commands give the operator access to the information stored in the CRYSTAL file. Commands are provided which enable lines to be entered, changed, deleted or printed on the terminal. List group commands can be divided into two groups:

1. List entry operations

Commands Function

LO List Output kappa angles

LK List Kill

LI List Input by indices and angles

LH List input by HKL's

LPH List input from polaroid Photo

LG List Get

LD List Dump

2. Status code operations

Commands Function

LCH List Change HKL status code

LCT List Change Theta status code

LCA List Change Angle status code

LCO List Change Orientation control status code

LCI List Change Intensity control status code

LCS List Change Scan information status code

LCL List Change Learnt profile status code

The reflection list

The CRYSTAL file consists of 28 records of 512 bytes of which the first 25 records hold a list of up to 25 reflections and the last 3 records contain parameters used during operation of the CAD4-program, such as wavelengths, orientation matrix elements, datcol values etc.. The data of these reflections are used for orientation matrix determination and intensity and orientation control during data collection. The CRYSTAL file information may be supplied by the operator or may be generated via SEARCH. The reflection centering routines and data collection modify the list as necessary. Each record of 512 bytes is used to store binary information pertaining to one reflection and, if required, information on 7 equivalent reflections used during the alignment procedure. Information relating to one reflection may be manipulated using any of the list entry operations described in Section D of this Chapter. The list may be printed as ASCII characters using LO. Other list group commands modify the various parameters.

In the CAD4 system the crystal file is linked to logical unit number 1. For file preparation see Initiating the CAD4 system. The contents of the first part of each record can be displayed alpha numerically on the terminal by the "LO" command. The example below is used to identify all parameters by their value.

Example:

CD0> LO<CR>
From to: 12<CR>
12 H 0 5 0 T 12.67 S 77.71 12.82 -3.31 OIS -3 0.59 9370.4
CD0>

Explanation:

Internal code Value Function

LISTNR 12 Line number in the CRYSTAL file

IRSIND H Status of the indices

RH 0

RK 5 The three indices

RL 0

IRSTH T Status of the THETA angle

RTHETA 12.67 The THETA angle

IRSANG S Status of PHIK, OMK, KAPPA and THETA angles

RPHIK 77.71 PHIK

ROMK 13.82 The Kappa geometry angles OMK

RKAPPA -3.31 KAPPA

IRSCOR 0 Indicator for orientation control

IRSCIN I Indicator for intensity control

IRSSCN S Status of the scan information

IRNPI -3 Attenuator setting, scan speed parameter

RSCANG 0.59 Scan angle

RSCINT 9370.4 Net intensity

A detailed description of the parameters identified in the example given above is given here.

LISTNR The line number in the CRYSTAL file where this reflection is stored, range 1 - 25.

IRSIND The status of the indices.
* - There is no valid index information present.
H - Index information is present.
N - Index information is present, but this reflection may not be used by INDEX, LS, REIND.
Index status is determined by a flag used by the geometry commands. IRSIND can be modified by LCH.

RH, RK, RL The indices of the reflection.
These indices are stored as real rather than integer values. When they are calculated by INDEX, LS and REIND they are converted to the nearest integer. They are stored as floating point numbers because all calculations involving them are floating point calculations.

IRSTH The status of the THETA angle.
* - The THETA angle was not determined by DETTH.
T - The THETA angle was determined by DETTH, independent of the zero error of the detector.
T inhibits redetermination of the THETA angle during subsequent recentering. IRSTH can be modified by LCT.

RTHETA The THETA angle in degrees.
2 THETA is twice as much

IRSANG The status of all of the angles.
* - No valid angle information is present; the line is empty. Not printed with LO.
P - LPH was used to input the angle information from a Polaroid rotation photograph, PHOTO must be used to locate the reflection(determine PHIK) and optimize all setting angles subsequently.
A - Angle information is present.
S - Angle information was determined by one of the centering routines SEARCH, PHOTO, SETANG, DETTH. Recentering is inhibited.
Q - Angle information was determined by SET4, as averaged from 4 equivalent reflections. Recentering is inhibited.
T - Angle information was determined by the texture programs
IRSANG can be modified by LCA.

RPHIK Kappa geometry angle PHIK.

ROMK Kappa geometry angle OMEGAK.

RKAPPA Kappa geometry angle KAPPA

IRSCOR Indicator for orientation control.
* - This reflection is not used for orientation control or orientation redetermination during data collection.
0 - This reflection is to be used for orientation control during data collection if selected (see
write-up of data collection control parameters). Also used for orientation redetermination.
R - This reflection is to be used for orientation redetermination during data collection.
IRSCOR can be modified by LCO.

IRSCIN Indicator for intensity control.
* - This reflection is not used for intensity control during data collection.
I - This reflection is to be used for intensity control.
F - This reflection was used for intensity control, but:
1. The reflection was "WEAK" when first measured at the start of data collection.
2. During a subsequent measurement the measured intensity dropped more than the allowable fraction of the original intensity (INTCR = FADING) and the operator forced data collection to continue after a "FADING" message was printed. This reflection will not be used again for intensity control.
IRSCIN can be modified by LCI.

IRSSCN The status of the scan information.
* - No valid scan information is present.
Non-valid scan information may be printed however.
S - Scan information is present and was determined by the reflection centering.
I - Scan information is present and was determined when the reflection was measured for the first time as an intensity control reflection. Further changes are inhibited. The commands DATCOL and DATCON do not change IRSSCN.
C - In a previous SETANG attempt a collision was sensed. Scan information may be valid but will not be used without changing the status back to "S".
D - In a previous SETANG attempt the detector limit switch was sensed. Scan information may be valid but will not be used without changing the status back to "S".
N - During a previous SETANG attempt only noise was sensed. Scan information may be valid but will not be used without changing the status back to "S".
T - In a previous SETANG attempt the buffer counter capacity was exceeded. Scan information may be valid but will not be used without changing the status back to "S".
W - In a previous SETANG attempt the reflection was found to be weak. Scan information may be valid but will not be used without changing the status back to "S".
X - In a previous SETANG attempt chie became to high. Scan information may be valid but will not be used without changing the status back to "S".
IRSSCN can be modified by LCS.

IRNPI The scan speed and attenuator setting. A minus sign indicates that the attenuator was used to measure this reflection. Scan speed = 16.49/IRNPI degree/min in omega.

RSCANG The scan angle for OMEGA axis.
This scan angle is three times the width of the peak as determined by subroutine PEAKD. See the description of PEAK ANALYSIS under SCAN (see Crystal orientation: Peak analysis).

RSCINT The net intensity of the peak when measured using IRNPI and RSCANG.
When IRSSCN = S, the net intensity is determined by subroutine PEAKD after the final OMEGA scan.
When IRSSCN = I, the net intensity is determined in the data collection way:
RSCINT = INT-2*(BGL+BGR), with INT equals the number of counts picked up during steps 17-80 and BGL and BGR being the number of counts collected during steps 1-16 and 81-96, respectively.

Command format of reflection list operations

1. List entry operations (Cf. the section on List entry operations of this page)

From the seven commands of this group the commands LD, LI, LH and LPH are used by the operator to fill the list. These commands do not need a line number, but fill the first empty line in reflection list (the CRYSTAL file). Apart from the command LD they all prompt for input.

The remaining commands require an line number or a line number range as input. The operator should specify, in the line following the command, the line number or numbers (inclusive) of the lines in reflection list (the CRYSTAL file) on which the command will operate, e.g.,

CD0> LO<CR>
From to: 1<CR>
line 1 from reflection list (the CRYSTAL file) is printed
CD0>
CD0> LO<CR>
From to: 2,6<CR>
lines 2 to and inclusive 6 from reflection list(the CRYSTAL file) are printed
CD0>

2. Status code operations (Cf. the section on Status code operations of this page)

The program will print, on a single line, the specified status code for the lines being examined/or modified, followed by "OK?". The operator may respond with "Y" if the status codes are correct, or may modify some or all of them by typing, on a single line, the correct sequence of codes. Empty lines included in the set examined are flagged with a "K". This "K" code cannot be changed. The examination cycle will be repeated until the operator is satisfied and types "Y" or "YES". The new codes will then be stored in the list.

General CAD4 input rules apply, including "/" to retain a code; "Q" may be used to escape the loop without effecting any changes.

CD0> LCH<CR>
From to: 1,7<CR>
H*H*NHH OK?
/HH//N<CR>
H*H*NNH OK?
////H//<CR>
H*H*HNH OK?
Y<CR>
CD0> LCA<CR>
From to: 1 10<CR>
ASASSPSSSS OK?
//////A***A<CR>
ASASSPA*** OK?
Y<CR>
CD0>

List entry operations

LO List Output.
Print the contents of one or more lines of the CRYSTAL file on the terminal in Kappa geometry. Empty lines are ignored.

LK List Kill.
Delete single or multiple lines from the CRYSTAL file.

LI List Input.
LI enables the operator to fill lines in the CRYSTAL file by typing in indices and angles. LI fills the lowest numbered empty line. The program will prompt for the required input, accept the input, then prompt for input the next empty line, if any. The operator must escape from this loop by typing Q if any lines remain unfilled.
The program prompts: n H K L T P O K?
n is the line number of the line to be filled in the CRYSTAL file. H K L are the indices which need not be integers. T P O K are the Kappa geometry angles, THETA, PHIK, OMK, KAPPA.
CD0> LI<CR>
4 H K L T P O K?
8,0,0,12.32,34.64,-78.94,128.72<CR>
5 H K L T P O K? Q<CR>
CD0>

LH List input by HKL's only.
LH enables the operator to fill entries in the CRYSTAL file by typing in only the indices and the psi value. The Kappa geometry angles will be calculated and placed in the list also. The orientation matrix R and the wavelength LAM1 must be available. LH fills the lowest numbered empty line. The program will prompt for the required input, accept the input, then prompt for input for the next empty line if any. The operator may escape from this loop by typing Q.
The program prompts: n H K L Psi? n is the line number of the line to be filled in the CRYSTAL file. H K L are the indices which need not be integers. Psi is the azimuth angle. It will be input as 0 in most cases.
CD0> LH<CR>
5 H K L Psi?
1 3 -2 0<CR>
6 H K L Psi? Q<CR>
CD0>

LPH List PHoto.
LPH enables the operator to type in X-Y separations of reflections found on a Polaroid rotation photograph. These reflections must be located by the PHOTO routine. LPH fills the first empty line in the CRYSTAL file. The program will prompt for the required input, accept the input, then prompt for input for the next empty line. The operator may escape from this loop by typing Q.
The Polaroid rotation photograph: Position the goniometer to the Polaroid photograph position (THETA =67.5, PHIK = 0, OMK = -150, KAPPA = 0) with the command POLA.
CD0> POLA<CR>
CD0>
Mount the Polaroid cassette on the Omega axis and tighten the set screw. Set the LOAD/PROCESS lever to LOAD. Insert the film pack firmly with "this side toward lens" away from the crystal. Pull out the film pack until it stops. Pull the EXPOSE knob out. Make a 360 degrees PHI scan with SCAN. (Takes about 10 min.)
CD0> SCAN<CR>
MM? P<CR>
SA N R?
360 0<CR>
!a meaningless output line will appear!
CD0>
If a longer exposure is needed, use the manual control to rotate the PHI axis with the shutter opened.
Push the EXPOSE knob back in. Push the film pack firmly back in. Move the LOAD/PROCESS lever to PROCESS. Pull the film pack out smoothly. Wait 15 seconds for the print to develop. Separate the film pack and peel off the print. The print may be preserved by coating it.
Analyzing the photograph:
Place the photograph with the long axis horizontal. Each observed reflection and its Friedel paired equivalent produce four symmetrically placed spots. For each set of four spots measure the horizontal distance X and the vertical distance Y between spots. An example of a rotation photograph is given in Fig. IX.1.

Fig. IX.1 Polaroid rotation photograph.
Put these values into the list: The program will prompt: n X Y? n is the line number of the line to be filled in the CRYSTAL file. X Y are the coordinates as measured above, in mm.
CD0> LPH<CR>
6 X Y?
9.5,45<CR>
7 X Y?
23,31<CR>
25 X Y?
Q<CR>
CD0>
The program calculates the angles for each reflection and places them in the list with the angle status set to P, indicating that the PHI values are not known. The calculation uses the value PDIST as stored in the GCONST file (Cf. section C. of Chapter VII), the distance between the cassette and the crystal. The command PHOTO is used to find the PHI value of each reflection and then center it, changing the angle status from P to S.

LG List Get. LG transfers the information in a single line of the CRYSTAL file to memory. The line number must be specified. Nothing is printed and the "DOT" points to the Kappa geometry. If the line is empty, "Illegal command!" is printed.
CD0> LG<CR> From to: 7<CR> CD0>

LD List Dump.
LD transfers information from memory into the first empty line in the CRYSTAL file. An implicit .K translation is performed and the angle information is stored in Kappa geometery with the angle status set to A. If valid index information is present that is also stored. The index status is set to H if the indices are integer. The index status is set to N if the indices are fractional. The line number of the line filled is printed. If the CRYSTAL file is already full the message 'Full list' will be printed.
CD0> LD<CR>
8
CD0> LD<CR>
Full list
CD0>
Please note that the CAD4 monitor returns a question mark as response to the command LD if no information is stored in memory.

Status code operations

Seven commands enable the operator to modify the status codes of single or multiple lines of the CRYSTAL file. Only modifications which make sense are permitted.

LCH Modify IRSIND, the index status code.
* - There is no valid index information present.
H - Index information is present.
N - Index information is present but this relection may not be used by INDEX, LS, REIND.
Valid modifications are:
H to N
N to H
* to N (After confirming this it is possible to modify N to H by a new LCH command.)

LCT Modify IRSTH, the THETA angle status code.
* - The THETA angle was not determined by DETTH.
T - The THETA angle was determined by DETTH. T inhibits redetermination of the THETA angle by SETANG and DETTH.
Valid modifications are:
T to *

LCA Modify IRSANG, the status of the angles.
* - No valid angle information is present; the line is empty.
P - Angle information was calculated from X Y separations on Polaroid rotation photograph. The PHI angle is not known. See the command LPH and PHOTO.
A - Angle information is present.
S - Angle information was determined by centering the reflection via SEARCH, PHOTO, SETANG or DETTH. Recentering is inhibited.
Q - Angle information was determined by SET4, as averaged from 4 equivalent reflections. Recentering and learning is inhibited.
T - Angle information was determined by the texture programs
Valid modifications are:
S to A Enables recentering by SETANG, DETTH or SET4.
Q to A Enables recentering by SETANG, DETTH or SET4.

LCO Modify IRSCOR, the data collection orientation control indicator.
* - This reflection is not to be used for orientation control or orientation redetermination.
O - This reflection is to be used for orientation control and orientation redetermination.
R - This reflection is to be used for orientation redetermination.
Valid modifications are:
-everything is allowed-
* to O
O to *
* to R
R to *
O to R
R to O

LCI Modify IRSCIN, the data collection intensity control indicator.
* - This reflection is not to be used for intensity control
I - This reflection is to be used for intensity control.
F - This reflection was used for intensity control, but:
1. Reflection was "WEAK" when first measured.
2. The reflection has faded; during data collection the measured intensity dropped more than the allowable fraction(spec ified by the operator through FRACTION) of the original intensity and the operator forced data collection to continue. This reflection will not be used again.
Valid modifications are:
* to I
I to *
F to I
F to *

LCS Modify IRSSCN, the status of the scan information.
* - No scan information is present. Non valid scan information may exist and may be printed, however. Default values from SETPAR will be used by SETANG.
S - Scan information is present and was determined by the reflection centering routine.
I - Scan information is present and was determined by DATCOL, when the reflection was measured for the first time as an intensity control reflection.
C - During centering a hardware collission occurred. If this happened the HKL-status is reset to N simultaneously.
D - During centering the detector limit switch was sensed. If this happened the HKL-status is reset to N simultaneously.
N - During centering noise was detected. If this happened the HKL-status is reset to N simultaneously.
W - During centering the reflection was found weak. If this happened the HKL-status is reset to N simultaneously.
X - During centering chi became too high. If this happened the HKL-status is reset to N simultaneously.
LCS:(contd) Valid modifications are:
S to *
I to S or *
C to S or *
D to S or *
N to S or *
T to S or *
W to S or *
X to S or *

LCL Modify the learnt profile indicator and print the currently stored profile
* - This reflection has not been used in the learnt profile routine
L - This reflection has been used in the learnt profile routine
Valid modifications are:
L - *

Previous: CAD4 control commands
Next: Crystal orientation routines

Commands	Function
LO	List Output kappa angles
LK	List Kill
LI	List Input by indices and angles
LH	List input by HKL's
LPH	List input from polaroid Photo
LG	List Get
LD	List Dump

Commands	Function
LCH	List Change HKL status code
LCT	List Change Theta status code
LCA	List Change Angle status code
LCO	List Change Orientation control status code
LCI	List Change Intensity control status code
LCS	List Change Scan information status code
LCL	List Change Learnt profile status code

Explanation:
Internal code	Value	Function
LISTNR	12	Line number in the CRYSTAL file
IRSIND	H	Status of the indices
RH	0
RK	5	The three indices
RL	0
IRSTH	T	Status of the THETA angle
RTHETA	12.67	The THETA angle
IRSANG	S	Status of PHIK, OMK, KAPPA and THETA angles
RPHIK	77.71	PHIK
ROMK	13.82	The Kappa geometry angles OMK
RKAPPA	-3.31	KAPPA
IRSCOR	0	Indicator for orientation control
IRSCIN	I	Indicator for intensity control
IRSSCN	S	Status of the scan information
IRNPI	-3	Attenuator setting, scan speed parameter
RSCANG	0.59	Scan angle
RSCINT	9370.4	Net intensity

LISTNR	The line number in the CRYSTAL file where this reflection is stored, range 1 - 25.
IRSIND	The status of the indices. * - There is no valid index information present. H - Index information is present. N - Index information is present, but this reflection may not be used by INDEX, LS, REIND. Index status is determined by a flag used by the geometry commands. IRSIND can be modified by LCH.
RH, RK, RL	The indices of the reflection. These indices are stored as real rather than integer values. When they are calculated by INDEX, LS and REIND they are converted to the nearest integer. They are stored as floating point numbers because all calculations involving them are floating point calculations.
IRSTH	The status of the THETA angle. * - The THETA angle was not determined by DETTH. T - The THETA angle was determined by DETTH, independent of the zero error of the detector. T inhibits redetermination of the THETA angle during subsequent recentering. IRSTH can be modified by LCT.
RTHETA	The THETA angle in degrees. 2 THETA is twice as much
IRSANG	The status of all of the angles. * - No valid angle information is present; the line is empty. Not printed with LO. P - LPH was used to input the angle information from a Polaroid rotation photograph, PHOTO must be used to locate the reflection(determine PHIK) and optimize all setting angles subsequently. A - Angle information is present. S - Angle information was determined by one of the centering routines SEARCH, PHOTO, SETANG, DETTH. Recentering is inhibited. Q - Angle information was determined by SET4, as averaged from 4 equivalent reflections. Recentering is inhibited. T - Angle information was determined by the texture programs IRSANG can be modified by LCA.
RPHIK	Kappa geometry angle PHIK.
ROMK	Kappa geometry angle OMEGAK.
RKAPPA	Kappa geometry angle KAPPA
IRSCOR	Indicator for orientation control. * - This reflection is not used for orientation control or orientation redetermination during data collection. 0 - This reflection is to be used for orientation control during data collection if selected (see write-up of data collection control parameters). Also used for orientation redetermination. R - This reflection is to be used for orientation redetermination during data collection. IRSCOR can be modified by LCO.
IRSCIN	Indicator for intensity control. * - This reflection is not used for intensity control during data collection. I - This reflection is to be used for intensity control. F - This reflection was used for intensity control, but: 1. The reflection was "WEAK" when first measured at the start of data collection. 2. During a subsequent measurement the measured intensity dropped more than the allowable fraction of the original intensity (INTCR = FADING) and the operator forced data collection to continue after a "FADING" message was printed. This reflection will not be used again for intensity control. IRSCIN can be modified by LCI.
IRSSCN	The status of the scan information. * - No valid scan information is present. Non-valid scan information may be printed however. S - Scan information is present and was determined by the reflection centering. I - Scan information is present and was determined when the reflection was measured for the first time as an intensity control reflection. Further changes are inhibited. The commands DATCOL and DATCON do not change IRSSCN. C - In a previous SETANG attempt a collision was sensed. Scan information may be valid but will not be used without changing the status back to "S". D - In a previous SETANG attempt the detector limit switch was sensed. Scan information may be valid but will not be used without changing the status back to "S". N - During a previous SETANG attempt only noise was sensed. Scan information may be valid but will not be used without changing the status back to "S". T - In a previous SETANG attempt the buffer counter capacity was exceeded. Scan information may be valid but will not be used without changing the status back to "S". W - In a previous SETANG attempt the reflection was found to be weak. Scan information may be valid but will not be used without changing the status back to "S". X - In a previous SETANG attempt chie became to high. Scan information may be valid but will not be used without changing the status back to "S". IRSSCN can be modified by LCS.
IRNPI	The scan speed and attenuator setting. A minus sign indicates that the attenuator was used to measure this reflection. Scan speed = 16.49/IRNPI degree/min in omega.
RSCANG	The scan angle for OMEGA axis. This scan angle is three times the width of the peak as determined by subroutine PEAKD. See the description of PEAK ANALYSIS under SCAN (see Crystal orientation: Peak analysis).
RSCINT	The net intensity of the peak when measured using IRNPI and RSCANG. When IRSSCN = S, the net intensity is determined by subroutine PEAKD after the final OMEGA scan. When IRSSCN = I, the net intensity is determined in the data collection way: RSCINT = INT-2*(BGL+BGR), with INT equals the number of counts picked up during steps 17-80 and BGL and BGR being the number of counts collected during steps 1-16 and 81-96, respectively.

LO	List Output. Print the contents of one or more lines of the CRYSTAL file on the terminal in Kappa geometry. Empty lines are ignored.
LK	List Kill. Delete single or multiple lines from the CRYSTAL file.
LI	List Input. LI enables the operator to fill lines in the CRYSTAL file by typing in indices and angles. LI fills the lowest numbered empty line. The program will prompt for the required input, accept the input, then prompt for input the next empty line, if any. The operator must escape from this loop by typing Q if any lines remain unfilled. The program prompts: `n H K L T P O K?` n is the line number of the line to be filled in the CRYSTAL file. H K L are the indices which need not be integers. T P O K are the Kappa geometry angles, THETA, PHIK, OMK, KAPPA. `CD0> LI<CR>` `4 H K L T P O K?` `8,0,0,12.32,34.64,-78.94,128.72<CR>` `5 H K L T P O K? Q<CR>` `CD0>`
LH	List input by HKL's only. LH enables the operator to fill entries in the CRYSTAL file by typing in only the indices and the psi value. The Kappa geometry angles will be calculated and placed in the list also. The orientation matrix R and the wavelength LAM1 must be available. LH fills the lowest numbered empty line. The program will prompt for the required input, accept the input, then prompt for input for the next empty line if any. The operator may escape from this loop by typing Q. The program prompts: `n H K L Psi?` n is the line number of the line to be filled in the CRYSTAL file. H K L are the indices which need not be integers. Psi is the azimuth angle. It will be input as 0 in most cases. `CD0> LH<CR>` `5 H K L Psi?` `1 3 -2 0<CR>` `6 H K L Psi? Q<CR>` `CD0>`
LPH	List PHoto. LPH enables the operator to type in X-Y separations of reflections found on a Polaroid rotation photograph. These reflections must be located by the PHOTO routine. LPH fills the first empty line in the CRYSTAL file. The program will prompt for the required input, accept the input, then prompt for input for the next empty line. The operator may escape from this loop by typing Q. The Polaroid rotation photograph: Position the goniometer to the Polaroid photograph position (THETA =67.5, PHIK = 0, OMK = -150, KAPPA = 0) with the command POLA. `CD0> POLA<CR>` `CD0>` Mount the Polaroid cassette on the Omega axis and tighten the set screw. Set the LOAD/PROCESS lever to LOAD. Insert the film pack firmly with "this side toward lens" away from the crystal. Pull out the film pack until it stops. Pull the EXPOSE knob out. Make a 360 degrees PHI scan with SCAN. (Takes about 10 min.) `CD0> SCAN<CR>` `MM? P<CR>` `SA N R?` `360 0<CR>` !a meaningless output line will appear! `CD0>` If a longer exposure is needed, use the manual control to rotate the PHI axis with the shutter opened. Push the EXPOSE knob back in. Push the film pack firmly back in. Move the LOAD/PROCESS lever to PROCESS. Pull the film pack out smoothly. Wait 15 seconds for the print to develop. Separate the film pack and peel off the print. The print may be preserved by coating it. Analyzing the photograph: Place the photograph with the long axis horizontal. Each observed reflection and its Friedel paired equivalent produce four symmetrically placed spots. For each set of four spots measure the horizontal distance X and the vertical distance Y between spots. An example of a rotation photograph is given in Fig. IX.1. Fig. IX.1 Polaroid rotation photograph. Put these values into the list: The program will prompt: n X Y? n is the line number of the line to be filled in the CRYSTAL file. X Y are the coordinates as measured above, in mm. `CD0> LPH<CR>` `6 X Y?` `9.5,45<CR>` `7 X Y?` `23,31<CR>` `25 X Y?` `Q<CR>` `CD0>` The program calculates the angles for each reflection and places them in the list with the angle status set to P, indicating that the PHI values are not known. The calculation uses the value PDIST as stored in the GCONST file (Cf. section C. of Chapter VII), the distance between the cassette and the crystal. The command PHOTO is used to find the PHI value of each reflection and then center it, changing the angle status from P to S.
LG	List Get. LG transfers the information in a single line of the CRYSTAL file to memory. The line number must be specified. Nothing is printed and the "DOT" points to the Kappa geometry. If the line is empty, "Illegal command!" is printed. CD0> LG<CR> From to: 7<CR> CD0>
LD	List Dump. LD transfers information from memory into the first empty line in the CRYSTAL file. An implicit .K translation is performed and the angle information is stored in Kappa geometery with the angle status set to A. If valid index information is present that is also stored. The index status is set to H if the indices are integer. The index status is set to N if the indices are fractional. The line number of the line filled is printed. If the CRYSTAL file is already full the message 'Full list' will be printed. `CD0> LD<CR>` `8` `CD0> LD<CR>` `Full list` `CD0>` Please note that the CAD4 monitor returns a question mark as response to the command LD if no information is stored in memory.

LCH	Modify IRSIND, the index status code. * - There is no valid index information present. H - Index information is present. N - Index information is present but this relection may not be used by INDEX, LS, REIND. Valid modifications are: H to N N to H * to N (After confirming this it is possible to modify N to H by a new LCH command.)
LCT	Modify IRSTH, the THETA angle status code. * - The THETA angle was not determined by DETTH. T - The THETA angle was determined by DETTH. T inhibits redetermination of the THETA angle by SETANG and DETTH. Valid modifications are: T to *
LCA	Modify IRSANG, the status of the angles. * - No valid angle information is present; the line is empty. P - Angle information was calculated from X Y separations on Polaroid rotation photograph. The PHI angle is not known. See the command LPH and PHOTO. A - Angle information is present. S - Angle information was determined by centering the reflection via SEARCH, PHOTO, SETANG or DETTH. Recentering is inhibited. Q - Angle information was determined by SET4, as averaged from 4 equivalent reflections. Recentering and learning is inhibited. T - Angle information was determined by the texture programs Valid modifications are: S to A Enables recentering by SETANG, DETTH or SET4. Q to A Enables recentering by SETANG, DETTH or SET4.
LCO	Modify IRSCOR, the data collection orientation control indicator. * - This reflection is not to be used for orientation control or orientation redetermination. O - This reflection is to be used for orientation control and orientation redetermination. R - This reflection is to be used for orientation redetermination. Valid modifications are: -everything is allowed- * to O O to * * to R R to * O to R R to O
LCI	Modify IRSCIN, the data collection intensity control indicator. * - This reflection is not to be used for intensity control I - This reflection is to be used for intensity control. F - This reflection was used for intensity control, but: 1. Reflection was "WEAK" when first measured. 2. The reflection has faded; during data collection the measured intensity dropped more than the allowable fraction(spec ified by the operator through FRACTION) of the original intensity and the operator forced data collection to continue. This reflection will not be used again. Valid modifications are: * to I I to * F to I F to *
LCS	Modify IRSSCN, the status of the scan information. * - No scan information is present. Non valid scan information may exist and may be printed, however. Default values from SETPAR will be used by SETANG. S - Scan information is present and was determined by the reflection centering routine. I - Scan information is present and was determined by DATCOL, when the reflection was measured for the first time as an intensity control reflection. C - During centering a hardware collission occurred. If this happened the HKL-status is reset to N simultaneously. D - During centering the detector limit switch was sensed. If this happened the HKL-status is reset to N simultaneously. N - During centering noise was detected. If this happened the HKL-status is reset to N simultaneously. W - During centering the reflection was found weak. If this happened the HKL-status is reset to N simultaneously. X - During centering chi became too high. If this happened the HKL-status is reset to N simultaneously. LCS:(contd) Valid modifications are: S to * I to S or * C to S or * D to S or * N to S or * T to S or * W to S or * X to S or *
LCL	Modify the learnt profile indicator and print the currently stored profile * - This reflection has not been used in the learnt profile routine L - This reflection has been used in the learnt profile routine Valid modifications are: L - *