9. In Case of Trouble

9.1 Emergency Stop

In increasing order of severity, motors can be stopped by:

There is an emergency stop button on each MEDM window which will cause the program to enter a soft abort sequence in which the motors will decelerate and stop without losing position.  If you abort a scan with the ABORT button, the motor(s) may try to return to their original position, depending on the settings of the scan parameters.  Use the STOP button.

Turn off motor power: Motors 1-8 (slits, 2q, pressure valve, and the pedestal motors) each have individual switches in the upper driver module (the one with the digital readouts). On the base motors (the lower driver module with the three fans), these switches are labeled:

MAN

OFF O ON

and there is one beneath each fan for each bank of motors. Bank 2 is for base Y and Phi, and bank 3 is for base Z. Bank 1 is no longer used.

Press the reset button on the appropriate E500. This will reset all the motors on the given E500! The pedestal-controlling E500 is on the right in slot 6; the one on the left, in slot 5 is for motors 1-8, (slits, 2q, and the base).

Note: the E500 assignments have been changed. E500 #1 controls motors 1-8 (incident slits and pedestal). E500 #2 has been removed. E500 #3 controls motors 17-24 (Dector X and Y, and conical slits. The remainder motors are controlled using the OMS VME cards, and can't be reset manually.

9.2 Motors don't Move

If you try to move a motor with its power switch turned off, or if the motor is not enabled, the CAMAC and computer will think the motor is moving when it is not. Press ^C to stop the CAMAC, then "drive" the motor back to its previous position without changing the switches. This will let the computer think it's back where it was, when actually it didn't move. Then turn on the power switch and enable the motor bank.

This needs to be updated for the OMS drivers.

9.3 No Data

There are several reasons there could be no data appearing on the MCA screen.

• 1. No x-rays - there could have been a beam dump which hasn't been announced yet.
  
• 2. The laser may have been left in the beam.
  
• 3. Warm detector. If the detector gets warm, its power supply will shut off. There will be a high count rate at very low energies. Refill the detector with liquid nitrogen, and let it cool down. It will take several hours to stabilize.  The 13 element detector may take 24 hours.
  
• 4. Detector power off. Whenever the detector is left alone and might warm up, its power supply should be turned off. If the detector is now cool, turn the power supply back on.

9.4 Label printer problems

Whenever a data file is saved, a label is printed with the filename and other information printed on it. You can hear the printer print each time. The way this is done is that a file called LABEL.PRN is created and saved in the data directory. If the label printer jams, or malfunctions in any other way, the label can be reprinted after the jam is cleared. Using the command prompt on the server computer, navigate to the data directory and type COPY LABEL.PRN LPT1: If the vertical alignment is off, you may have to make a manual adjustment and repeat the command.

There is only one LABEL.PRN file, so if label printer problems are not noticed immediately, that file is overwritten and all except the latest ones are lost. The information in the file, however, is also stored in the data file, and printed on the plot page described below.

9.5 Laser printer problems

As with the label printer, a page is printed on the laser printer for each data set. This includes 4 plots for the 4 detectors, and all the text data printed by the label printer. This involves a file called PAGE.PS, and is a PostScript encoded text page. Again, it is created for each file and overwritten, so errors must be corrected immediately. Reprinting that page involves copying PAGE.PS to any printer with native PostScript software. For the HP LaserJet 4MV-PS, use the command COPY PAGE.PS \\X17B2SRV\HPLJ4MVPS from the command line, as above.