~sober/manuals/tag_pwr_sup_local.txt
						27 July 1997


              Local Operation of the Hall B Tagger Power Supply


   COLD START

   1.    Turn on LCW to desired flow rate.

   2.    Turn on 440 VAC breaker at northeast wall of Hall.

   3.    Turn on power supply breaker at left front of cabinet.

   4.    Check that the two vent covers on the cabinet roof are not obstructed. 
         (They are taped down at one edge, and will swing upward when vent air
         flow is present.)

   5.    Press RESET button on control panel to reset the Air Flow interlock,
         which is always off at power up.

   6.    Check that all indicator lights on the Fault Module (FM) are on.

         * If "A FLOW" light is off, check that the air vents are uncovered.
         * If "W FLOW" light is off, increase the water flow to the power
            supply.
         * If "SPR1" light is off, check external interlocks (magnet
           temperature and magnet water flow)
         * If "MG" and "SF" lights are off, this indicates a blown fuse in the
           external interlock system.  Replace fuse F24EX in the TBEX
           terminal block behind the second door from the right in the rear.
         (Note:  A rewiring of the MG, SF and SPR1 interlocks to provide more
         information is contemplated.)

         Press RESET after correcting the condition.

   7.    Check that the Ready (RDY) light on the Control Module (CM) is on.

   8.    Check that the power supply is in REMOTE mode (REM light on, LOC
         light off on the Control Module (CM)).  The supply powers up in this
         mode.  From this point on, remote control should be possible.


   LOCAL OPERATION

   1.    The power supply powers up in REMOTE mode (REM light on, LOC light 
         off on the Control Module (CM)).  
      
         To change to LOCAL mode:

         1)   Press the MODE button (below the LCD display screen) until the 
              screen showing LOCAL and REMOTE appears.  The "*" indicates 
              the current option.
         2)   Press the SELECT button until the selection symbol ">" is 
              next to the LOCAL option.
         3)   Press the ENTER button to select LOCAL.  The "*" should now 
              appear after LOCAL, and the lights should show LOC = on, 
              REM = off on the Control Module (CM).

   2.    Check that polarity is correct (lights labeled NPOL (Normal) or 
         RPOL (Reversed) on the Control Module (CM).)

   3.    To reverse polarity:
      
         1)   Press STOP button.  Check that the supply is off (green OFF 
              light lit on the CM), AND that the current has decayed to 0 
              on the ammeter.
         2)   Press the MODE button (below the LCD display screen) until 
              the screen showing NORMAL POL and REVERSE POL appears.  
              The "*" indicates the current option.
         3)   Press the SELECT button until the selection symbol ">" is 
              next to the desired option.
         4)   Press the ENTER button to select the option.  The "*" should 
              now appear after the desired option, and the NPOL/RPOL 
              lights on the CM should also show this option.
      
   4.    Press START button to turn power on.

   5.    To set current:

         1)   Press MODE button (below LCD screen) until screen with "V0(V)" 
              and "I0(A)" appears.
         2)   Enter the desired number of amperes using the keypad, and 
              press the ENTER key promptly.  If you wait more than a few 
              seconds, the desired ampere setting (indicated on the LCD 
              screen) will reset to zero, and you must re-enter the
              amperes on the keypad.
         3)   When setting current for a run, ALWAYS use the complete 
              field-setting procedure (0 A for at least 3 minutes, 
              2400 A for 3 minutes, then lower to desired current).

   CHANGING THE MAGNET CURRENT

   1.    Set I = 0 A.
   2.    Leave I = 0 A for at least 3 minutes.
   3.    Set I = 2400 A.
   4.    Leave I = 2400 A for 3:00 minutes (use kitchen timer).
   5.    Set I to desired setting.
   6.    Allow magnet to stabilize for at least 15:00 minutes.
   
   
   DEGAUSSING THE MAGNET 

   Note: This procedure is normally done automatically by MCC at the end of
   a beam run.  If it is not done then, it can be done under local control
   as described here.  If you are not certain that the magnet has been
   degaussed, see the section VERIFYING THAT THE MAGNET HAS BEEN DEGAUSSED
   below.

   1.    Set I = 0 A.
   2.    Leave I = 0 A for at least 3 minutes.
   3.    Set I = 2400 A.
   4.    Leave I = 2400 A for 3:00 minutes (use kitchen timer).
   5.    Set I = 0 A, and wait for reading of 0 on the ammeter.
   6.    Press STOP button.
   7.    Reverse the magnet polarity to POSITIVE(="REVERSE").
   8.    Press START button.
   9.    Set I = 1000 A.  As soon as the current has stabilized (>999 on the
         ammeter), hold current for 15 seconds, then set I = 0.
   10.   When ammeter reads 0 A, press STOP button.
   11.   Reverse the magnet polarity back to NEGATIVE(="NORMAL".)
   12.   Turn off power supply breaker.


   VERIFYING THAT THE MAGNET HAS BEEN DEGAUSSED

   If you are not sure whether the magnet has been degaussed after the
   last photon beam run, take a hand-held gaussmeter to the upstream end
   of the magnet, near the radiator box.  The stainless steel top arc of 
   the vacuum chamber is accessible inside the magnet yoke.  If the magnet
   has not been degaussed, the magnetic field at the surface of the top
   arc can be as large as 20-30 gauss.  If the magnet has been degaussed,
   the field at the surface of the top arc should be less than 3 gauss.