HR-MAS Manual
4. Operation of the HR-MAS System

4.5 Spinning the rotor under computer control

 

The MAS window

 

In order to operate the MAS pneumatic unit from XWINNMR, the unit has to be run in remote mode, which can be selected on the keypad on the front of the unit. The set-up of and communication with the pneumatic unit is established by typing cfmas on the XWINNMR command line and answering the questions in accordance with your set-up.

 

The control of the pneumatic unit from the host computer is initiated by typing MAS on the command line. This brings up the MAS control window, shown in figure 4.4. Start by selecting the correct probe parameters or reading them in from a previously saved probe setup file.

 

Press Eject Sample to flip the stator in the upright position and eject a rotor which might be in the probe. After the eject air is off, insert the rotor and click Insert Sample to flip the stator to the magic angle position.

Enter the desired spinning rate and select spinning on to start spinning. By pressing Continuous Update the actual values of the bearing and drive pressure and the spinning rate will be updated every 10 s. After the rotor reaches the desired spinning rate and the spinning is stable, the Spin Locked parameter will be set to Yes.

Exit the menu by pressing cancel. The spin rate can still be monitored on the computer screen by selecting MAS rate monitor from the windows menu of XWIN-NMR.

 

Spinning can be halted by re-entering the MAS menu and selecting spinning off (note that when you enter the MAS window, spinning is always set to off, however, you will have to activate this to stop the spinner). Press Continuous Update to monitor the spinning rate. Once the spinner is stopped press Eject Sample to remove the sample.

 

Figure 4.4. MAS pneumatic unit control window.

 

Command line control

 

In addition to using the MAS window (figure 4.4) the following commands can be used to control the spinner from the command line of XWINNMR:

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