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nmr_probes [2019/10/21 15:41] pereira [Troubleshooting] |
nmr_probes [2023/10/24 08:17] noji wish is now wish8.6 |
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====== NMR Control ===== | ====== NMR Control ===== | ||
- | Two digital oscilloscopes are dedicated to NMR readout – one for the analysis line NMRs and one for the spectrograph NMRs. The scopes are located in data-U6, in upper two shelves on the right electronics rack. They are isolated from clean ground because this signals from the NMR probes are on a dirty ground. | + | Two digital oscilloscopes are dedicated to NMR readout – one for the analysis line NMRs and one for the spectrograph NMRs. The scopes are located in the S3 mezzanine. They are isolated from clean ground because this signals from the NMR probes are on a dirty ground. |
===== Motivation ===== | ===== Motivation ===== | ||
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===== Description ===== | ===== Description ===== | ||
- | The NMR running programs for both the S800 analysis line and spectrograph dipoles can be started | + | The NMR running programs for both the S800 analysis line and spectrograph dipoles can be started |
- | Sometimes the initialization of these applications fail. In that case check section [[nmr probes# | + | $ ssh [your-user-name-on-EXP]@exp-s3-nmr -Y |
+ | |||
+ | and typing, for the analysis line dipoles | ||
+ | |||
+ | $ / | ||
+ | |||
+ | and for the spectrograph dipoles | ||
+ | |||
+ | $ / | ||
+ | |||
+ | **Note that it is not simply wish anymore but wish8.6.** | ||
+ | Now press start on the GUI, which is shown below, and you should see a field reading. | ||
{{: | {{: | ||
+ | ===== Terminating processes run by another user ===== | ||
+ | |||
+ | A solution has been implemented for the case where one user needs to run the NMR software via the ' | ||
+ | |||
+ | If a user is running ' | ||
+ | |||
+ | * Log on to exp-s3-nmr virtual machine (as described above) | ||
+ | * Type 'ps aux | grep wish' to find out the name of the user that is running wish | ||
+ | * Let's suppose user ' | ||
+ | * This will stop both wish processes that are running as user ' | ||
+ | * Now user ' | ||
+ | |||
+ | In short, | ||
+ | $ ps aux | grep wish | ||
+ | $ sudo -u usernameRunningWish pkill wish | ||
+ | | ||
+ | and you should be able to run the NMR software. | ||
===== 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 maximum number of attempts is limited to 200. After that the status is marked as " | 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 " | ||
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* The terminal server is behind the NMR controllers | * The terminal server is behind the NMR controllers | ||
* Simply turn it off, wait few seconds, and turn it back on | * Simply turn it off, wait few seconds, and turn it back on | ||
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+ | |||
+ | |||
+ | ==== Spectrograph NMR GUI " | ||
+ | * This is typically the case when the thresholds in the NMR GUI are not set properly. If they are too low, the program may lock in noise. Conversely, if the thresholds are too high, it may miss a weak resonance. | ||
+ | * Threshold for the Spectrograph resonance can be adjusted by hand in the Spectrograph NMR GUI. In general, a threshold 0.15 mV is good for normal NMR signals, whereas 0.10 mV may be necessary if the signal are too weak. | ||
+ | |||
==== Manually setting Dipole Fields | ==== Manually setting Dipole Fields |