Steven Blusk
							ORC for Barrel 4
							12/17/99
							
		
I.		    Barrel 4 Monitoring
		    ===================



1.   2 RTD's on each bulkhead, T_i (i=1,4)
2.   1 RTD at the inlet cooling manifold T_in
3.   1 RTD in drybox volume (T_drybox)
4.   1 RH sensor in drybox (rh)

5.   1 Flow Transmitter (Flow)
6.   1 Pressure transmitter at return (P_ret)
7.   1 Pressure difference transmitter (DPT)
8.   1 Control Valve (CV)
9.   From 6 and 7, one can calculate the supply pressure
     P_sup.



II.		   Interlocks Protection
		   =====================


#1. Temperature Interlocks (prevents overheating of SVX-II ladders)
    ---------------------------------------------------------------

   T_in, T_i (i=1,4) < 22 C  (in PLC, cannot be changed
			      without password)
         and
   T_in, T_i (i=1,4) < T_user  (can be changed in iFix


#2. Pressure Interlocks (prevents overpressurization of bulkhead)
    -------------------------------------------------------------

   P_ret < 15 PSI    (in PLC cannot be changed without password)
        and 
   P_ret < P_ret_user  (can be changed in iFix)

	AND

   P_sup < 27 PSI    (in PLC cannot be changed without password)
        and 
   P_sup < P_sup_user  (can be changed in iFix)

#3. Dew Point Interlock (prohibits condensation)
    --------------------------------------------

   From rh and T_drybox, we calculate the dew point temperature,
T_dp, and require

     T_i (i=1,4) > (T_dp + 3.0) C


#4. Cooling Interlocks
    ------------------

   If either Interlock #2 or Interlock #3 trips, then
   
    CV = 0  (flow turned off)
    PS = 0  (Power to SVXII ladders is turned off)

#5. Power Supply Interlocks
   -----------------------   

   Power supply cannot be enabled without a 5V Enable.
The requirements for this 5V Enable are:

  (a) CAEN PS Enable is set on iFix
  (b) Interlocks #1-#3 are NOT tripped   
  (c) coolant is being delivered to the bulkhead
      (Flow>0 and CV>0)


   d) There are also current limits in the supply, which,
      if exceeded, cause the PS to trip off. There is no
      iFix display for this trip as of yet.  

==> Any trip (except for #5d)) also causes the sound alarm on 
    the front of the Interlock rack to be enabled. There is a bypass
    to temporarily to  disable it until the problem is resolved.


III.		Recovery from an Interlock Trip
		===============================


   Possible causes of a trip are:
   ------------------------------


   Cause		  Result	  Action
   -----		  ------	  ------		
* One (or more) of the    * Trip #1, #5    * Fix problem with RTD
RTD's becomes partially   * Possibly #3    * After problem is fixed
or fully disconnected.			     hit "Alarm Acknowledge"
					   * Re-enable audio alarm
					   * Turn CV to 60%
					   * Click "CAEN PS Enable"

* Chiller fails to        * Trip #1, #5    * Check setpoint of chiller
  cool water, or 	  * Possibly #3    * Contact expert for 
  temp. setpoint			   
  is inadvertently
  increased


* Vacuum pump		  * Trip #2, then  * Contact expert to
  dies		 	    Trip #4, then  * replace vacuum pump
			    Trip #5	     and reestablish enables


* RH transmitter          * Trip #3, then  * Replace RH sensor
  dies			    Trip #4 and 
			    Trip #5

* Overcurrent in PS       * PS Trips off   * Contact expert


IV. General prescription for recovery from a trip
    =============================================

a) Go to iFix and pull up "Barrel4" drawing

b) Hit "Alarm Acknowledge" button. (Make sure you hit the button!)
 
   - If all alarm conditions have been rectified, then all the
     blinking "TRIP" signs will disappear.

   - Turn control valve (CV) to 60 (60%)
   
   - Re-enable the CAEN PS

c) If the blinking trip lights do not all go off, the problem
   has not been fixed, and  you cannot run the CAEN PS and
   possibly the cooling. In this case you will need to contact an 
   expert.