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\documentclass{chowto}

\title{How to Set the HMS Magnets}
\howtotype{user} % ``expert'', ``user'', ``reference''
%\experiment{Name of experiment} % Optional
\author{Mike Fowler and Dave Gaskell}
\category{magnet} % Subject area of this document
%\maintainer{Name of person maintaining document} % Optional
\date{\today} % Can use \today as the argument

\begin{document}

\begin{abstract}
This document describes how one determines and sets the needed 
currents/fields for the HMS magnets (quadrupoles and dipole).
\end{abstract}

\section{Calculate Magnet Settings}\label{field}

The HMS magnet settings are calculated using the program ``field03''.  This
program will provide the needed set--currents for Q1, Q2, and Q3, and the
needed field for the dipole.  To
access this program, log into cdaqs1 or cdaqs3 as cdaq. Go to the 
\texttt{FIELD} directory (\texttt{cd FIELD}) and run \texttt{field03}. An 
example follows:\\
\vspace*{0.2in}\\
\texttt{cdaqs1> field03}\\
 \texttt{Input HMS momentum in GeV, electron is negative.}\\
\texttt{-2.0}\\
  \texttt{Field03 program}\\
 \texttt{Set current for Q1 =     260.49874122486 amps}\\
 \texttt{Set current for Q2 =    -207.05390149569 amps}\\
 \texttt{Set current for Q3 =    100.945638467771 amps}\\
 \texttt{Set NMR for Dipole =   -0.54971654308813 Tesla}\\


\section{Setting the Magnets - Quick--Start Guide}

\subsection{Select a magnet}

The quadrupoles (and the dipole) are set from the keyboard and screen in 
in the central controls console, under the large TV screens.  Note that
the actual controls PC's (a separate one for each magnet) are in the Hall and 
we are using a remote screen and keyboard.  The same screen is used to display 
the controls for all 4 HMS magnets.  

One must switch the screen from magnet--to--magnet using a 
sequence of keyboard commands.  This sequence is referred to as the
``NumLock--minus--NumLock'' or the NmN sequence.  To select a magnet:

\begin{itemize}
\item{Press and hold the \texttt{NumLock} key.}
\item{Press and hold the \texttt{-} key.}
\item{Release the \texttt{-} key.}
\item{Release the \texttt{NumLock} key.}
\item{Press one of the following:}\\
%\begin{itemize}
%	\item{\texttt{a} for Q1}
%	\item{\texttt{b} for Q2}
%	\item{\texttt{c} for Q3}
%	\item{\texttt{d} for the dipole}
%\end{itemize}
	\texttt{a} for Q1\\
	\texttt{b} for Q2\\
	\texttt{c} for Q3\\
	\texttt{d} for the dipole\\
\item{Hit \texttt{return}.}
\end{itemize}



\subsection{Set the quadrupoles}\label{quad_set}

This section assumes that all the quadrupoles are already on, at the 
correct polarity, and functioning normally.  If they are not at the correct
polarity, see Section~\ref{quadpol}.

If you are changing the current to a {\bf{smaller}} value:

\begin{itemize}
\item{Select the magnet (see above).} 
\item{Select the \texttt{Command Line} window with the arrow keys on the
keyboard.}
\item{Type \texttt{psu:setcur:xxx.xx}, where \texttt{xxx.xx} is the absolute 
value of the current from the magnet setting program.}
\item{Hit enter - the magnet should start ramping to the desired current.}
\end{itemize}

If you are changing the current to a {\bf{larger}} value:

\begin{itemize}
\item{Select the magnet (see above).} 
\item{Select the \texttt{Command Line} window with the arrow keys on the
keyboard.}
\item{Set the current to 200 Amps {\bf{above}} the current calculated
in the magnet setting program.  Type \texttt{psu:setcur:yyy.yyy}, where 
\texttt{yyy.yy} is the absolute value of the current determined in the magnet 
setting program + 200.  Hit enter and wait for the magnet to reach the current
you just typed in.}
\item{Type \texttt{psu:setcur:xxx.xx}, where \texttt{xxx.xx} is the absolute 
value of the current from the magnet setting program.}
\item{Hit enter - the magnet should start ramping to the desired current.}
\end{itemize}

Note that on occasion one must enter the relevant command (psu:setcur:xxx.xx 
for example) more than once before the control computer will respond.  It is in
general a good idea to watch for about 30 seconds to see if the computer 
responds to your command.  If it does not, just re--enter the command.

\subsection{Set the dipole}\label{setdipole}

The dipole can be set in three modes: Current Control, Manual NMR Field 
Control, and Automatic NMR Controlled Ramp.  The default method is at the
discretion of the experiment -- consult your run coordinator.  In this 
section, setting the dipole using automatic NMR controlled ramp will be discussed.  To switch  
to another operation mode, the dipole current must be zero.


\subsubsection{Automatic NMR Controlled Ramp (Field Regulation Mode) - Starting from Zero}

\begin{itemize}
\item{Select the dipole screen on the magnet controls console.}
\item{Press F1 to go to the dipole main menu screen.}
\item{Check the interlock status in the upper right corner of the main menu. If the interlock
status field is flashing red:}

  \begin{itemize}
    \item{Using the arrow keys, position the cursor over the \texttt{INTERLOCK} menu item.
      Type \texttt{exe} and press ENTER.}
    \item{Position the cursor over the \texttt{RESET INTERLOCK} menu item. Type
      \texttt{exe} and press ENTER.}
    \item{Press F1 and return to main menu.}
  \end{itemize}

\item{Position the cursor over the \texttt{FIELD REGULATION} menu item - then type 
{\texttt{exe}} and press ENTER.}

\item{Position the cursor over the \texttt{DEFAULT mode} menu item.  Type \texttt{exe}
and press ENTER.}

\item{Position the cursor over the \texttt{NMR start, PWR on} menu item, type \texttt{exe} and
press ENTER.  After approximately one minute the NMR unit is activated.  The NMR is on when the status
field is white starts on a green background.} 

\item{Position the cursor over the \texttt{Set DEFAULT values} menu item, type \texttt{exe} and press
ENTER.}

\item{Position the cursor over the \texttt{high} value menu item, type \texttt{exe} and press ENTER.}

\item{Type in the first 4 digits of the desired magnetic field and hit ENTER.  For the example field from 
field03 shown in Section~\ref{field} (0.5497165 T), the first 4 digits are 0549 for 0.549.}

\item{Position the cursor over the \texttt{low} value menu item, type \texttt{exe} and press ENTER.}

\item{Type in the last 4 digits of the desired magnetic field and hit ENTER. Example: for 0.5497165 T, type
7165.}

\item{Position the cursor over the \texttt{CLOSE} menu item, type \texttt{exe} and press ENTER.}

\item{Position the cursor over the \texttt{Start Excitation} menu item, type \texttt{exe} and press ENTER.}

\item{The dipole will now follow the excitation curve and ramp to the desired field.}

\end{itemize}


\subsubsection{Changing the HMS Dipole Field in Regulation Mode}

\begin{itemize}

\item{Position the cursor over the \texttt{Set DEFAULT values} menu item, type \texttt{exe} and 
press ENTER.}

\item{Position the cursor over the \texttt{high} menu item, type \texttt{exe} and 
press ENTER.}

\item{Type in the first 4 digits of the desired magnetic field and hit ENTER.  For the example field from 
field03 shown in Section~\ref{field} (0.5497165 T), the first 4 digits are 0549 for 0.549.}

\item{Position the cursor over the \texttt{low} value menu item, type \texttt{exe} and press ENTER.}

\item{Type in the last 4 digits of the desired magnetic field and hit ENTER. Example: for 0.5497165 T, type
7165.}

\item{Position the cursor over the \texttt{CLOSE} menu item, type \texttt{exe} and press ENTER.}

\item{Position the cursor over the \texttt{Start Excitation} menu item, type \texttt{exe} and press ENTER.}

\item{The dipole will now follow the excitation curve and ramp to the desired field.}
\end{itemize}

\subsubsection{HMS Dipole Ramp up-err/ Field crtl-err}

Occasionally the NMR unit terminates the field ramp up/down or terminates the field control.
When this happens, the \texttt{Ramp up-err} or \texttt{Field  crtl-err} will change to red.
You should always record any fault indications in the hclog, then perform the following:

\begin{itemize}
\item{Position the cursor over the \texttt{RESET} menu item next to the error indicator, type
\texttt{exe} and press ENTER. The NMR unit will continue the ramp up/down or restart
field control.}
\end{itemize}

\section{More information about the Quadrupoles}

\subsection{Changing the quadrupole polarity}\label{quadpol}

The HMS quadrupole polarity can be changed as follows:

\begin{itemize}

\item{If the magnet is not at zero current, ramp it to zero
by typing \texttt{psu:setcur:0.0} in the \texttt{Command Line} box.}

\item{When the magnet reaches zero current, type \texttt{psu:pol:+} or
\texttt{psu:pol:-} for positive or negative polarity.}

\item{At its new polarity, ramp the magnet to its maximum current (Q1=950 Amps, Q2=900 Amps, Q3=850 Amps): 
\texttt{psu:setcur:xxx.x}.}

\item{You can now ramp the magnet down to the desired current: 
\texttt{psu:setcur:xxx.xx}, \texttt{xxx.xx} is the absolute value of the 
current desired.}

\end{itemize}


\subsection{HMS Quadrupole Interlock Recovery}

Occasionally, an HMS quad power supply will trip off because a real or 
annoyance power supply fault is sensed. Prudent checks of the system temperature,
pressure, and liquid level are wise. You should always record any fault 
indications in the hclog! Once you have determined that the fault is not real 
or that it has been corrected, and that there is no indication of a quench, 
the power supply may be reset by executing the following commands:

\begin{itemize}
\item{Type \texttt{psu:setcur:0.0} in the Command Line box.}
\item{WAIT for the magnet to finish ramping to zero current/field (if it 
hasn't already).}
\item{Type \texttt{reset}.}
\item{Type \texttt{psu:reset}.  All red faults should now be green.  If they 
are not, type \texttt{reset} and \texttt{psu:reset} again.}
\item{Type \texttt{psu:on}.  Note that the read LED for the magnet alarms 
(near the target computer) will not go off until this step.}
\item{Set the magnet to desired current using the procedure described in 
Section~\ref{quad_set}.}
\end{itemize}

\subsection{Quadrupole Quench/Dump Switch Open Interlock}

Recovery from a quadrupole quench can be done remotely. There is little 
or no possibility of a ``real" quench occurring in the main coils so one
should always reset and continue. Prudent checks of the system temperature, 
pressure and liquid level are wise. You should record any fault indications
in the hclog! There have been real quenches of the trim
coils that subsequently cause enough noise to trip the main coil off. There 
are other causes of fast discharges but these have all been the result of 
electrical noise or a detection level set too low. There have been no real 
quenches observed of any quad main coil. When a quench reset is needed, the 
dump switch open interlock and main coil quench interlock are shown on the 
ILK screen of the quadrupole display screen.

To remotely reset the dump switch execute the following steps in the proper 
order:

\begin{itemize}
\item{Position the cursor over the {\texttt{ILK}} box and press Enter.}
\item{In the Command Line box type \texttt{qreset}.  The Main Coil Quench and/or
the Current Lead Overvoltage interlock will change to green.}
%\item{\texttt{reset}}
\item{Wait 7 minutes for the Dump Switch Open interlock to change to green.}
\item{Position the cursor over the {\texttt{PSU}} box and press Enter.}
\item{Type \texttt{psu:reset}.  The MPS OVERTEMP indicator will turn green.}
\item{Type \texttt{psu:on} and set the magnet as normal.}
\end{itemize}

To manually reset the dump switch at the control rack in the hall (if you have
not done this before, try to get some help):

\begin{itemize}
\item{Press RESET buttons on control rack (button \#1).}
\item{Press button \#2 on the QUENCH SWITCH.}
\item{Press button \#3.}
\item{Press button \#4.}
\item{(wait seven minutes with rabbit foot)}
\item{Press RESET button on control rack (button \#5).}
\item{Type 'psu:reset'.}
\item{Type 'psu:on'. }
\end{itemize}


\subsection{Rebooting the HMS quadrupole computers}

Occasionally, one or more of the magnet control computers will become hung,
stop responding, or cease to function.  If this is the case, check the hall
quadrupole hall probes and dipole NMR readback values on the TV monitors.  If
they are still at their nominal values, it is NOT necessary to reboot the
computer right away.  You may wait until some opportune moment, i.e. when 
changing kinematics or when beam may go away for an extended period.

When you do decide to reboot the affected PC, first check the Reboot How--to
\cite{reboot}.  The steps to follow for the quadrupoles are are summarized below.

\begin{itemize}
\item{Rebooting the quad computer will crash the magnet so make sure
you are really ready to reboot!}
\item{Go to the screen of the affected computer (NumLock-minus-NumLock, etc.).}
\item{Go to the reboot panel (on cdaqs1) and reboot that PC.}
\item{The PC will come up with two ``sections''.  On startup, the cursor will
be in the bottom (blue?) section.  Get to the top section by hitting the 
\texttt{Esc} key. NOTE: If the display remains blank after the reboot and you do not 
see the startup screen, go to one of the other magnet screens, then back to the screen
of the affected computer.}
\item{Now you can move the cursor to the "PSU" box - hit ENTER to get to the PSU screen.}
\item{The screen will show an "MPS OVERTEMP" fault.  This is OK.}
\item{If the setcurrent readback value is not 0.0, type \texttt{psu:setcur:0.0} in the Command Line box.  
The MPS not ready will change from ``Not Ready'' to ``Ready'' when the current is zero.}
\item{Type \texttt{psu:reset}.  MPS OVERTEMP will change to green.}
\item{Wait 7 minutes or until the MPS OVERTEMP changes to red.}
\item{Type \texttt{psu:reset}.  The MPS OVERTEMP should change to green. If not, repeat \texttt{psu:reset}.}
\item{Type \texttt{psu:on} and set the magnet current as you would normally.}
\end{itemize}

\section{More information about the Dipole}

\subsection{Turning the dipole power supply on}

\begin{itemize}
\item{In Hall C, unlock the and turn on the dipole main breaker.}
\item{Turn on the dipole power supply switch located on top of the power supply.}
\item{Open the center door and press the diode reset button. Close the door.}
\item{Press RESET to clear the interlocks on the power supply. NOTE: One interlock will remain red.}
\item{Turn the NMR on.}
\end{itemize}

\subsection{Changing the dipole polarity}

\begin{itemize}

\item{To change the dipole, first let the dipole ramp to zero current - the current can be forced to
ramp down quickly by:}

\begin{itemize}
	\item{Position the cursor over the \texttt{Interlock} menu item. Type \texttt{exe} and press
	  ENTER.}
	\item{Position the cursor over the \texttt{Fast Discharge by user} menu item. Type \texttt{exe} and 
	  press ENTER.}
\end{itemize}
\item{You can monitor the dipole current in the upper left corner of the \texttt{INTERLOCK}
page. Wait until the current readback is zero.}

\item{Position the cursor over the \texttt{Reset Interlock} menu item. Type \texttt{exe} and press ENTER.}

\item{Press F1 (function key \# 1) to return to the Main Menu.}

\item{Position the cursor over the \texttt{Field Regulation, NMR Manual op.}, or the \texttt{MPS Manuel op.} menu item,
depending on which mode is being used. Type \texttt{exe} and press ENTER.}

\item{Position the cursor over the \texttt{NMR start, PWR on} menu item. Type \texttt{exe} and press ENTER.
After approximately one minute the NMR unit is activated.  The NMR is on when the status
field is white starts on a green background.}

\item{Position the cursor over the \texttt{Change +/-} menu item. Type \texttt{exe} and press ENTER.}

\item{Once the polarity has changed, set the dipole using the instructions in
Section \ref{setdipole}.}

\end{itemize}


\subsection{Dipole Quench Recovery / Interlock Recovery }

The recovery from a dipole quench ``real or imaginary" can be completely remote. It is wise to check the 
coil voltages, system temperature, pressure, and liquid levels before restarting. You should always record 
any fault indications in the hclog! A restart requires the following steps. 

\begin{itemize}

\item{Position the cursor over the \texttt{Interlock} menu item. Type \texttt{exe} and press ENTER.}
\item{Monitor the current value in the upper left corner. Wait until the current read back is zero.}
\begin{itemize}
   \item{The current can be forced to ramp down quickly. Position the cursor over the \texttt{Fast Discharge by 
     user} menu item. Type \texttt{exe} and press ENTER.}
\end{itemize}
\item{Position the cursor over the \texttt{Reset Interlock menu item}. Type texttt{exe} and press ENTER.}
\item{Go to the reboot panel (on cdaqs1) and reset the Dipole Power Supply Diode}
\item{Press F1 (function key \# 1) to return to the Main Menu.}
\item{Position the cursor over the \texttt{Field Regulation, NMR Manual op.}, or the \texttt{MPS Manual op.} page, 
depending on the mode of operation being used.}
\item{Position the cursor over the \texttt{NMR start, PWR on} menu item, type \texttt{exe} and press ENTER.
After approximately one minute the NMR unit is activated. The NMR is on when the status field is white 
stars on a green background.}
\item{Set desired current or field.}
\end{itemize}

The HMS dipole has never had a real quench. Even the failure of a current lead in October '93 did not 
quench the coil, according to the Hall C engineering staff. There have been numerous fast/slow discharges 
and all were due to electrical noise, low trip settings, deliberate operator initiated trips, or interlock 
dissatisfaction. 

\subsection{HMS Dipole NMR-err / MPS-err}
A NMR-err or MPS-err indicates that a communication error has occurred between the control system and 
the NMR unit and/or the Power Supply. You should always record any fault indications in the hclog! 

\begin{itemize}
\item{Set the Magnet alarms (near the target computer) to Bypass.}
\item{Position the cursor over the \texttt{Interlock} menu item. Type \texttt{exe} and press ENTER.}
\item{Monitor the current value in the upper left corner. Wait until the current read back is zero.}
\begin{itemize}
\item{The current can be forced to ramp down quickly. Position the cursor over the \texttt{Fast Discharge by 
user} menu item. Type \texttt{exe} and press ENTER.}
\end{itemize}
\item{Press F1 (function key \# 1) to go to the Main Menu.}
\item{Position the cursor over the \texttt{Field Regulation, NMR Manual op.}, or the 
\texttt{MPS Manual op.} page, depending on the mode of operation being used. Type \texttt{exe} 
and press ENTER.}
\item{Position the cursor over the \texttt{RS232 restart} menu item, type \texttt{exe} and press ENTER.}
\item{Press F7 (function key \# 7) to go to the \texttt{Device} page.}
\item{Wait for all the devices to restart. }
\item{Position the cursor over the \texttt{Reset Interlock} menu item. Type \texttt{exe} and press ENTER.}
\item{Go to the reboot panel (on cdaqs1) and reset the Dipole Power Supply Diode.} 
\item{Press F1 (function key \# 1) to return to the Main Menu.}
\item{Position the cursor over the \texttt{Field Regulation, NMR Manual op.}, or the \texttt{MPS Manual op.}
 page, depending on the mode of operation being used. Type \texttt{exe} and press ENTER.}
\item{Position the cursor over the \texttt{NMR start, PWR on} menu item, type \texttt{exe} and press ENTER.
After approximately one minute the NMR unit is activated. The NMR is on when the status field 
is white stars on a green background.}
\item{The field or current may now be set.}
\item{Set the Magnet alarms (near the target computer) to Active.}
\end{itemize}

\subsection{Restricting the NMR }
The NMR unit is very sensitive to electromagnetic interference, so when the unit is searching for the 
magnetic field the unit will try to lock in on a NMR signal without magnetic field. For most cases the NMR 
will simply attempt to lock in on the interference for a short period of time, then give up and continue on. 
However, when ramping the Dipole to high field levels, (0.50 T and above), the NMR unit will try to lock in 
on several interference signals and may never reach the magnet field set point after several Ramp up-err 
resets. When this happens it is possible to restrict the number of probes that the NMR will search and 
improve the probability of obtaining a good field lock. Perform the following steps to restrict the number of 
probes.

NOTE: The procedure only works when the Dipole is at zero amps.
\begin{itemize}
\item{Press F1 (function key \# 1) to go to the Main Menu.}
\item{Position the cursor over the \texttt{NMR manual op.} menu item, type \texttt{exe} and press ENTER.}
\item{Position the cursor over the \texttt{Multiplexer} menu item, type \texttt{exe} and press ENTER.}
\item{Position the cursor over the \texttt{Number of multiplexer channel} menu item, type 
\texttt{exe} and press ENTER.}
\item{Type in \texttt{1}, and press ENTER.}
\item{Position the cursor over the \texttt{Start multiplexer channel} menu item, type \texttt{exe}
 and press ENTER.}
\item{Type in the probe number from the chart below, and press ENTER.}
NMR Probes:
\begin{tabular}{cc}
Probe \#	&	Range (Tesla)   \\
   2	&	0.09T - 0.26T \\
   3	&	0.17T - 0.52T \\
   4	&	0.35T - 1.05T \\
   5	&	0.70T - 2.10T 
\end{tabular}

\item{Position the cursor over the \texttt{Write field multiplexer parameter} menu item, type \texttt{exe} and press 
ENTER.}
\item{Position the cursor over the \texttt{NMR stop, PWR off}  menu item, type \texttt{exe} and press ENTER.}
\item{Position the cursor over the \texttt{NMR start, PWR on} menu item, type \texttt{exe} and press ENTER.}

\end{itemize}

\subsection{Setting the HMS Dipole in current control mode }

Perform the following steps to operate the dipole in current control mode. 

\subsubsection{MPS Manual operation: Starting from zero.}

\begin{itemize}
\item{Press F1 (function key \# 1) to go to the Main Menu.}
\item{Check the Interlock status, upper right corner of the main menu.
If the interlock status field is flashing red:}

\begin{itemize}
\item{Using the arrow keys, position the cursor over the \texttt{Interlock} menu item. 
Type \texttt{exe} and press ENTER.}
\item{Position the cursor over the \texttt{Reset Interlock} menu item. Type \texttt{exe} and press ENTER.}
\item{Press F1 to return to the Main Menu.}
\end{itemize}

\item{Position the cursor over the MPS Manual op. menu item. Type EXE and press Enter.}
\item{Position the cursor over the \texttt{NMR start, PWR on} menu item, type \texttt{exe} and press ENTER.
After approximately one minute the NMR unit is activated. 
The NMR is on when the status field is white stars on a green background.. }
\item{Position the cursor over the \texttt{Set current high} menu item, type \texttt{exe} and press ENTER.}
\item{Type high current value 0 to 3000 for integer part of the current in Amps, and press ENTER.}
\item{Position the cursor over the \texttt{Set current low} menu item, type \texttt{exe} and press ENTER.}
\item{Enter low bit current value 0 to 999 for 0.000 to 0.999 amps.}
\item{Position the cursor over the \texttt{Automatic measurements} menu item, type \texttt{exe} and press ENTER.}
\item{Position the cursor over the \texttt{Write set data} menu item, type \texttt{exe} and press ENTER.}
\item{The Dipole will now ramp to the desired current.}
\end{itemize}

\subsubsection{MPS Manual operation: Changing the current value}
\begin{itemize}
\item{Position the cursor over the \texttt{Set current high} menu item, type \texttt{exe} and press ENTER.}
\item{Type high current value 0 to 3000 for integer part of the current in Amps, and press ENTER.}
\item{Position the cursor over the \texttt{Set current low} menu item, type \texttt{exe} and press ENTER.}
\item{Enter low bit current value 0 to 999 for 0.000 to 0.999 amps. }
\item{Position the cursor over the \texttt{Write set data} menu item, type \texttt{exe} and press ENTER.}
\item{The dipole will now ramp to the new current.}
\end{itemize}

\subsection{Setting the HMS Dipole in NMR Manual operation }


\subsubsection{NMR Manual operation: Starting from zero.}
\begin{itemize}
\item{Press F1 (function key \#1) to go to the Main Menu.}
\item{Check the Interlock status, upper right corner of the main menu.
     If the interlock status field is flashing red:}
\begin{itemize}
\item{Using the arrow keys, position the cursor over the \texttt{Interlock} menu item. Type \texttt{exe} and press 
ENTER.}
\item{Position the cursor over the Reset Interlock menu item. Type \texttt{exe} and press ENTER.}
\item{Press F1 to return to the Main Menu.}	
\end{itemize}
\item{Position the cursor over the \texttt{NMR manual op.} menu item, type \texttt{exe} and press ENTER.}
\item{Position the cursor over the \texttt{NMR start, PWR on} menu item, type \texttt{exe} and press ENTER.
After approximately one minute the NMR unit is activated. 
The NMR is on when the status field is white stars on a green background.}
\item{Position the cursor over the \texttt{Auto Measurement} menu item, type \texttt{exe} and press ENTER.}
\item{Position the cursor over the \texttt{Field Target Value} menu item, type \texttt{exe} and press ENTER.
The field target value is a 32 bit word split into two 16 bit words, high and low.}
\item{Position the cursor over the \texttt{high value} menu item, type \texttt{exe} and press ENTER.}
 \item{Type in the field target value high word, and press ENTER. 
(Example: For 1.2345678 T  type 1234 )}
 \item{Position the cursor over the \texttt{low value} menu item, type \texttt{exe} and press ENTER.
(Example: For 1.2345678 T  type 5678 )}
\item{Position the cursor over the Write field target values menu item, type \texttt{exe} and press ENTER.}
\item{Wait (The dipole power supply will ramp the magnet.
After the power supply has ramped the magnet, the Searchmode will automatically switch to on.) 
The NMR unit will search for the field, lock on, and calculate the regulation window. When this 
calculation is complete, and if successful, the NMR-status 5 will change to 1, and the auto 
measurements will switch  to manual measurement.) }
\begin{itemize}
\item{If the NMR-status 5 displays a value other than 1 visit the web site \\ 
\texttt{http://www.jlab.org/$\sim$fowler/nmrstatusie.htm} \\ and enter the NMR register values to obtain 
more details. You should always record any fault indications in the hclog!}
\end{itemize} 
\item{Position the cursor over the \texttt{Auto Measurement} menu item, type \texttt{exe} and press ENTER.}
\item{Position the cursor over the \texttt{Field-ctrl ON} menu item, type \texttt{exe} and press ENTER.}
\item{Wait ( The Searchmode will automatically switch on, and the NMR will reacquire field lock. 
The NMR will then make adjustments to the power supply, and if successful, the NMR-status 5 
will change to 1, and the auto measurements will switch to manual measurement.)}
\begin{itemize}
\item{If the NMR-status 5 is not set to 1 then an error has occurred.}
\item{Position the cursor over the Field-ctrl OFF menu item, type \texttt{exe} and press ENTER.}
\item{Return to the previous step (turn \texttt{Field-ctrl ON}).}
\end{itemize}
\item{Position the cursor over the \texttt{Auto Measurement} menu item, type \texttt{exe} and press ENTER.}
\item{Wait (It takes approximately three minutes for the NMR to fine tune the field to the set value.
When the NMR finished, the field the NMR-status 5 will change to 8, and the auto measurements 
will switch to manual measurement.)}
\item{Position the cursor over the \texttt{Auto Measurement} menu item, type \texttt{exe} and press ENTER.}
\item{The Dipole is now ready.}
\end{itemize}

\subsubsection{NMR Manual operation: Changing the field target value}
\begin{itemize}
\item{Position the cursor over the \texttt{Field-ctrl OFF} menu item, type \texttt{exe} and press ENTER.}
\item{Position the cursor over the \texttt{Field Target Value} menu item, type \texttt{exe} and press ENTER.}
\item{Position the cursor over the \texttt{high value} menu item, type \texttt{exe} and press ENTER.}
\item{Type in the field target value high word, and press ENTER.} 
\item{Position the cursor over the \texttt{low value} menu item, type \texttt{exe} and press ENTER.}
\item{Type in the field target value low word, and press ENTER. }
\item{Position the cursor over the \texttt{Write field target values} menu item, type \texttt{exe} and press ENTER.}
\item{Position the cursor over the \texttt{Auto Measurement} menu item, type \texttt{exe} and press ENTER.}
\item{Wait (The dipole power supply will ramp the magnet.
After the power supply has ramped the magnet, the Searchmode will automatically switch to on.) 
The NMR unit will search for the field, lock on, and calculate the regulation window. When this 
calculation is complete, and if successful, the NMR-status 5 will change to 1, and the auto 
measurements will switch  to manual measurement.)}
\begin{itemize}
\item{If the NMR-status 5 is not set to 1 visit the web site \\
\texttt{http://www.jlab.org/$\sim$fowler/nmrstatusie.htm}\\ and enter the NMR register values to obtain 
additional details. You should always record any fault indications in the hclog!}
\end{itemize} 
\item{Position the cursor over the \texttt{Auto Measurement} menu item, type \texttt{exe} and press ENTER.}
\item{Position the cursor over the \texttt{Field-ctrl ON} menu item, type \texttt{exe} and press ENTER.}
\item{Wait ( The Searchmode will automatically switch on, and the NMR will reacquire field lock. 
The NMR will then make adjustments to the power supply, and if successful, the NMR-status 5 
will change to 1, and the auto measurements will switch to manual measurement.)}
\begin{itemize}
\item{If the NMR-status 5 is not set to 1 then an error has occurred.}
\item{Position the cursor over the \texttt{Field-ctrl OFF} menu item, type \texttt{exe} and press ENTER.}
\item{Return to the previous step (turn \texttt{Field-ctrl ON}).}
\end{itemize}
\item{Position the cursor over the \texttt{Auto Measurement} menu item, type \texttt{exe} and press ENTER.}
\item{Wait (It takes approximately three minutes for the NMR to fine tune the field to the set value.
When the NMR is finished, the NMR-status 5 will change to 8, and the auto measurements will 
switch to manual measurement.)}
\item{Position the cursor over the \texttt{Auto Measurement} menu item, type \texttt{exe} and press ENTER.}
\item{The Dipole is now ready.}
\end{itemize}

\subsection{Rebooting the dipole control computers}

Occasionally, one or more of the magnet control computers will become hung,
stop responding, or cease to function.  If this is the case, check the hall
quadrupole hall probes and dipole NMR readback values on the TV monitors.  If
they are still at their nominal values, it is NOT necessary to reboot the
computer right away.  You may wait until some opportune moment, i.e. when 
changing kinematics or when beam may go away for an extended period.

When you do decide to reboot the affected PC, first check the Reboot How--to
\cite{reboot}.  The steps to follow are summarized below.

\begin{itemize}

\item{Rebooting the HMS dipole computer will NOT crash the dipole, so this
can be done at any time.}

\item{Go to the dipole screen (NumLock-minus-NumLock, \texttt{D}, 
\texttt{return}.).}
\item{Go to the reboot panel (on cdaqs1) and reboot the dipole PC.}
\item{If the display remains blank after the reboot, go to a quadrupole screen, then
back to the dipole screen.}
\item{Once the computer has recovered, type \texttt{hms} at the prompt.  This
will start the magnet control program.}

\end{itemize}

\end{document}

% Revision history:
% $Log: set_hms_magnets.tex,v $
% Revision 1.5  2004/09/17 04:06:56  saw
% Include text from Mike Fowler
%
% Revision 1.4  2003/06/19 16:19:41  saw
% Add wait of 5 minutes after reboot.
%
% Revision 1.3  2003/06/12 16:03:45  saw
% (gaskelld) Add sections on how to reboot things + corrections.
%
% Revision 1.2  2003/04/11 02:39:22  saw
% (gaskelld) Include preliminary description of how to change HMS polarity
%
% Revision 1.1  2003/04/07 20:50:20  saw
% Initial Checkin
%