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nmr_probes [2013/12/14 11:16] pereira |
nmr_probes [2013/12/14 11:18] pereira [Troubleshooting] |
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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 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. | ||
- | ==== Motivation ==== | + | ===== Motivation |
Due to the location of the NMR probes in the dipoles of both the S800 analysis line and spectrograph, | Due to the location of the NMR probes in the dipoles of both the S800 analysis line and spectrograph, | ||
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- | ==== Description ==== | + | ===== Description |
The NMR running programs for both the S800 analysis line and spectrograph dipoles can be started by clicking on the icons labeled S800A_NMR and S800S_NMR, located on the desktop of uxpc2. The picture below shows the spectrograph GUI as an example. The top (yellow) panel shows the data relevant to the NMR module, the middle (pink) the digitized signal from the oscilloscope and the bottom (blue) the status and measurements for the dipoles. | The NMR running programs for both the S800 analysis line and spectrograph dipoles can be started by clicking on the icons labeled S800A_NMR and S800S_NMR, located on the desktop of uxpc2. The picture below shows the spectrograph GUI as an example. The top (yellow) panel shows the data relevant to the NMR module, the middle (pink) the digitized signal from the oscilloscope and the bottom (blue) the status and measurements for the dipoles. | ||
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- | ==== 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. | ||
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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 ): | ||
- | - telnet 35.8.35.139 | + | - **telnet 35.8.35.139** |
- | - enter any username | + | - enter any **username** |
- | - su | + | - **su ** |
- | - system | + | - **system** |
- | - unattach port x where x=1 for the analysis line and x=2 for the spectrograph | + | - **unattach port x** (where x=1 for the analysis line and x=2 for the spectrograph) |
- | - logout | + | - **logout** |
- Click again on the starting icon and the program should start. | - Click again on the starting icon and the program should start. | ||