This shows you the differences between two versions of the page.
Both sides previous revision Previous revision Next revision | Previous revision Next revision Both sides next revision | ||
nmr_probes [2013/12/14 16:20] pereira [Description] |
nmr_probes [2013/12/14 17:51] pereira [Operation] |
||
---|---|---|---|
Line 9: | Line 9: | ||
===== Description ===== | ===== Description ===== | ||
- | The NMR running programs for both the S800 analysis line and spectrograph dipoles can be started by clicking on the icons labeled | + | The NMR running programs for both the S800 analysis line and spectrograph dipoles can be started by selecting |
Line 16: | Line 16: | ||
===== Operation ===== | ===== Operation ===== | ||
- | The NMR program constantly checks the status of the various dipoles from the EPICS system and updates the status column. In addition, the program checks the log file at startup for the closest previously measured value. In case no previous measurement can be used the program searches for a signal around the guessed value of the field. This search can take some time if the calibration is off or the hysteresis of the dipole is large. | + | The NMR program constantly checks the status of the various dipoles from the EPICS system and updates the status column. In addition, the program checks the log file at startup for the closest previously measured value. In case no previous measurement can be used the program searches for a signal around the guessed value of the field. This search can take some time if the calibration is off or the hysteresis of the dipole is large. The maximum number of attempts is limited to 200. After that the status is marked as " |
In order to reduce the searching time, the program tries to guess the field from the following sources, in priority order: | In order to reduce the searching time, the program tries to guess the field from the following sources, in priority order: | ||
Line 26: | Line 26: | ||
* Calibration if no previous measurement is available | * Calibration if no previous measurement is available | ||
- | In addition, the program checks the log file at startup for the closest previously measured value. In case no previous measurement can be used the program searches for a signal around the guessed value of the field. This search can take some time if the calibration is off or the hysteresis of the dipole is large. The maximum number of attempts is limited to 200. After that the status is marked as “Failed” and the program gives up on this dipole. | ||
- | |||
Once a signal is found, the measuring sequence tries to find two resonance positions on either side of 0. Each resonance is calculated as the average between the negative and positive modulation minima (blue and green curves, and corresponding arrows). The final field is interpolated from those measurements, | Once a signal is found, the measuring sequence tries to find two resonance positions on either side of 0. Each resonance is calculated as the average between the negative and positive modulation minima (blue and green curves, and corresponding arrows). The final field is interpolated from those measurements, | ||
- | If a dipole is turned off or its field is being changed, the status shows either | + | If a dipole is turned off or its field is being changed, the status shows either |
+ | |||
+ | |||
+ | THIS FIGURE IS OBSOLETE. NEW A NEWER VERSION | ||
{{: | {{: | ||
- | The magnet currents, measured fields, and deviation from the set value are logged in a file that is soft-linked from the " | + | The magnet currents, measured fields, and deviation from the set value are logged in a file that is soft-linked from the " |
Line 47: | Line 48: | ||
===== Matching ===== | ===== Matching ===== | ||
- | {{: | + | The button labeled “Match” opens a new window for matching |
- | + | {{: | |
- | The button labeled “Match” opens a new window for matching | + | |
===== Troubleshooting ===== | ===== Troubleshooting ===== | ||
- | * The NMR program is connected to the following devices and systems: | + | The NMR program is connected to the following devices and systems: |
* The NMR module through a terminal server | * The NMR module through a terminal server | ||
Line 62: | Line 62: | ||
* The EPICS system through the caRepeater process launched by the et_wish shell running the program | * The EPICS system through the caRepeater process launched by the et_wish shell running the program | ||
- | Any of these connections can eventually be broken, and the program tries to catch the failures and report them to the user. However there are cases when the program | + | Any of these connections can eventually be broken, and the program tries to catch the failures and report them to the user. However there are cases when the program |
In case nothing happens after clicking on the icon, the connection to the NMR module is probably locked and needs to be freed. To free it, type the following from any shell window (actual typing show in this font ): | In case nothing happens after clicking on the icon, the connection to the NMR module is probably locked and needs to be freed. To free it, type the following from any shell window (actual typing show in this font ): |