System Settings
After the VnmrJ software is installed, it must be configured using the VnmrJ System Settings Window. The System Settings window provides software settings that are used more often than general spectrometer settings. 1. Log in as the VnmrJ administrator (e.g., vnmr1) and start VnmrJ. 2. After VnmrJ starts, click Edit in the main menu, then System Settings to open the System settings window,. The System Settings window has two tabs; System and Display Plot. The fields, drop down menus, and check boxes for each tab is shown below. Select the choices that are correct for the spectrometer system.
Application mode -- Standard, Walkup, imaging, LC-NMR.
Setting the Lock Frequency. The lock frequency must be set with the following procedure after VnmrJ is installed. The true 2H frequency is used. This procedure is not normally done again unless the magnet quenches or a large change in field strength occurs. 1. Make sure the magnet is “at field.” 2. If a water sample is not in the magnet, insert it. This can be tap water. 3. Set sw=500000, or sw=2000000 if wideline). 4. Set tn='H1' lockfreq='n'. 5. Enter ga. No peaks indicate the system is off resonance. By changing the value of tof (or array tof), locate the water resonance. Make the change 200 to 400 kHz, so each spectral window will overlap its neighbors. 6. Center the water resonance in the spectral window by placing the cursor on the line and entering movetof. 7. Acquire a spectrum with the line centered in the window. 8. Enter the command setlockfreq. The command setlockfreq calculates and sets the lock frequency parameter lockfreq.
Creating the Acqproc User On systems that include a magnet installation (spectrometers systems, not data stations), a series of daemons, known as the proc-family, direct communications between the host computer and the console. To allow all users to be able to enable and disable these daemons, become root and type the following command: # /vnmr/bin/makesuacqproc If you are not root yet, the system asks you for your root passwords. Now all users can enable or disable the daemons by typing the following command: user> su acqproc
Setting the Lock Frequency On system installations that include installing a magnet, the lock frequency must be set with the following procedure after VnmrJ is installed. The true 2H frequency is used. This procedure is not normally done again unless the magnet quenches or a large change in field strength occurs. 1. Make sure the magnet is “at field.” 2. If a water sample is not in the magnet, insert it. This can be tap water. 3. Set sw=500000, or sw=2000000 if wideline). 4. Set tn='H1' lockfreq='n'. 5. Enter ga. If you don’t see any peaks, the system is off resonance. By changing the value of tof (or array tof), locate the water resonance. Make the change 200-kHz- to 400-kHz, so each spectral window will overlap its neighbors. 6. Center the water resonance you located in the spectral window by placing the cursor on the line and entering movetof. 7. Acquire a spectrum with the line centered in the window. 8. Enter the command setlockfreq. Note setlockfreq calculates and sets the lock frequency parameter lockfreq.
Configuration window to configure NMR spectrometer hardware. 1. In the System Settings window, click the System config button. The VnmrJ Spectrometer Configuration window opens, shown at the right.
2. Check that the configuration values are correct for your system. 3. Configure each rf channel. 4. Click OK to save the configuration settings or Cancel and make no changes. 5. Click OK to save the system settings or Cancel to make no changes and close the System Settings window. 6. When changing from a datastation to a spectrometer, exit and restart VnmrJ to enable acquisition features in the main menu.
Return to the Main Instrument Page or Main NMR Page.
