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\large
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\centerline {\bf 4.10\_V2.1 PUT ACIS INTO MEMORY SAVE MODE } 
\vspace{0.25in}

\normalsize
\noindent{\it Last Revised: August 25, 1999}\\
\noindent{\bf Filename: mem\_save} \\


\noindent {\bf BRIEF FUNCTIONAL DESCRIPTION:} \\

This procedure is intended to be used during the normal science
mission to prepare the ACIS instrument for eclipse passage during
which ACIS may be allowed to dissipate $\sim 21$~W as specified by
the spacecraft power budget. It is expected that the previous science run will
have been halted by a ``Stop Science'' command included in the daily
command load and scheduled at the appropriate time by the OFLS SW.
Nevertheless, since it is no harm to the instrument to send this
command twice, this command is sent again in this procedure.
The procedure then turns off all components {\it which are expected to
be on during the normal science mission (bakeout mode is not one of
the expected normal states of the instrument)} and leaves the DPA side
A on to preserve ACIS volatile memory.

\normalsize
\vspace{0.25in}
\noindent The sequence of actions will be: 
\be
\item issue a Stop Science Run command
\vspace{-0.10in}
\item turn off the video board power and  FEPS, stop DEA HKP, and dump
the system configuration
\vspace{-0.10in}
\item turn off the Detector Housing heater
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\item turn off the DEA side B and A
\vspace{-0.10in}
\item turn off the DPA side B
\ee


\vspace{0.15in}
\normalsize
\noindent {\bf ASSUMED INSTRUMENT STATE:} \\
\normalsize
Assumes the instrument is on and has just completed a science run. \\
The instrument should not be in bakeout mode. \\


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\normalsize
\noindent {\bf SPECIAL INITIAL CONDITIONS:} \\
\normalsize
None.

%\newpage 

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\normalsize
\noindent {\bf OPERATIONAL CONSTRAINTS/CAUTIONS:} \\
\normalsize
The active thermal control of the instrument is disabled by this
procedure so the DH and FP may approach survival temperatures.\\

\vspace{0.15in}
\normalsize
\noindent {\bf REFERENCES:} \\
\normalsize

{\bf V1.2}
\begin{itemize}
\item changed command to power-down the FEPs and video boards to be
``WSPOW00000'' in step 2.1
\item added a command to stop the DEA HKP run in step 2.2
\item changed the time delay in steps 4.2 and 4.4 to 1~s
\item added a step 6 to verify the proper state of ACIS
\end{itemize}

{\bf V2.0}
\begin{itemize}
\item ACIS Team signed-off version
\item changed HW TLM verifier in step 6.4 to ``1DEN1BVO''
\end{itemize}

{\bf V2.1}
\begin{itemize}
\item changed the order of commands in the previous steps 2.1 and 2.2
so that the ``stopDea'' command comes {\it before} the
``changeConfigSetting'' command which powers down the video boards.
\item changed the execution time for step 2.1 to 4.0s
\end{itemize}


\newcommand{\tablecaptiontext}{Put ACIS into Memory Save Mode}
\input{mem_save.tab}

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