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\newcommand{\axaf}{{\em AXAF}}

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\large
%\vspace*{-0.5in}
\centerline {\bf 4.30\_V2.5 TURN ON DEA B  }
\vspace{0.25in}

\normalsize
\noindent{\it Last Revised: August 10, 2017}\\
\noindent{\bf Filename: deab\_on} \\


\noindent {\bf BRIEF FUNCTIONAL DESCRIPTION:} \\
\normalsize
This is an ``atomic'' procedure which  powers up the B side of the DEA.
It should be safe to execute under any condition except a spacecraft
power or thermal emergency.
\vskip 0.2in
\noindent The sequence of actions for this procedure will be:
\be
\item Verify that DEA A is powered off and disabled (see Constraints/Cautions, below)
\vspace{-0.10in}
\item Verify that DEA B is recieving power from the spacecraft
\vspace{-0.10in}
\item Enable and turn on DEA power supply side B
\vspace{-0.10in}
\item Verify that DEA A is still powered off
\ee

\vspace{0.15in}
\normalsize
\noindent {\bf ASSUMED INSTRUMENT STATE:}
\normalsize
\be
\item Assumes that the PSMC is receiving power from the spacecraft.
\vspace{-0.10in}
\item Assumes that DEA A is off.
\vspace{-0.10in}
\item Assumes the DEA was previously powered from side B. If it was instead powered from side A, or if the prior state is unknown, the board 11 relays will need to be reset, as in the switch\_deaa\_b procedure.
\ee

\vspace{0.15in}
\normalsize
\noindent {\bf SPECIAL INITIAL CONDITIONS:} \\
\normalsize
%The environment must be clean enough to allow opening of the valve. \\
%Assumes that \axaf\/ ISIM RCTU is powered on and in telemetry format 6. \\

%\vspace{0.25in}
\normalsize
\noindent {\bf OPERATIONAL CONSTRAINTS/CAUTIONS:} \\
\normalsize
In normal operations, only one side of the DEA should be powered on
(a) to prevent conflict for control of the focal plane temperature controller,
(b) to avoid excess current draw from the spacecraft, and (c) to avoid over-heating
within the PSMC.

The DEA power status is normally indicated by the values of the 1DEPSA and
1DEPSB flags, which should not both be 1 simultaneously.
However, if neither side of the DPA is receiving power
({\it i.e.}, if 1DPP0AVO and 1DPP0BVO are simultaneously reading $0.0 \pm 0.5$ V),
the DEA flag values will be unreliable and the DEA voltage
channels (1DEP[0123][AB]VO) should instead be used to determine which
sides of the DEA are powered).

Before sending the command to power on DEA B, the DEA Input Voltage B 1DE28BVO
should be checked to make sure that DEA B is receiving power from the spacecraft.

The DEA input current monitors (1DEIC[AB]CU) are noisy.
To give an indication of what variation may be expected, figures 1 and 2
show the behavior of the A-side DEA current with a ten-sample running
average for two situations in which all video boards were powered down.
Note that when either side of the DEA is unpowered, the corresponding current monitor,
1DEICBCU for side B, or 1DEICACU for side A, will be unreliable.
They will read $16-18$~A when unpowered.
This is a feature of all TDB versions up through v14 and is not an anomaly.

If the DEA powers off unexpectedly during a bakeout, the FP bakeout heater will
lose power and this heater will NOT be re-enabled when the DEA side B power is
restored. Additional SW commands are necessary to activate the FP bakeout heater.
The DH bakeout heater is unaffected by a power loss to the DEA and will therefore
still be executing a bakeout if power is lost to the DEA.

After successful execution, {\em the FP temperature control will be unregulated,
and DEA interface A/D will be in low-resolution mode.}

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

\normalsize
\noindent {\bf CHANGE HISTORY:} \\
\normalsize

{\bf V1.0}
\begin{itemize}
\item Initial version, based on deaa\_on.
\end{itemize}

{\bf V1.1}
\begin{itemize}
\item Minor edits, for ACIS team review
\end{itemize}

{\bf V1.2}
\begin{itemize}
\item Added caution about using both DEA power supplies at once. 
For ACIS team review.
\end{itemize}

{\bf V1.3}
\begin{itemize}
\item Extra DEA-A off checks
\end{itemize}

{\bf V2.0}
\begin{itemize}
\item For FOT review
\end{itemize}

{\bf V2.1}
\begin{itemize}
\item Corrected expected voltages; added +28V input checks.
\end{itemize}

{\bf V2.2}
\begin{itemize}
\item Removed input current check; added warning to text.
\end{itemize}

{\bf V2.3}
\begin{itemize}
\item Added step 1.2 to verify the DEA B is receiving power from the spacecraft.
\item Added description of this to the brief functional description, and to the
constraints \& cautions section.
\item Added words about bakeout contingencies.
\item Added Telemetry Description identifiers to the DEA ENB/DIS and ON/OFF items.
\item Updated criticality values in the command table.
\item Minor word changes to match the side A procedure.
\end{itemize}

{\bf V2.4}
\begin{itemize}
\item Added warning about DEA relays if switching sides
\end{itemize}

{\bf V2.5}
\begin{itemize}
\item Clarified language per PGF comments.
\end{itemize}

\begin{landscape}
\begin{figure}
\begin{center}
\includegraphics[width=1.2\textwidth]{deaa_on_fig1.eps}
\caption{Ten-sample running average behavior of 1DEICACU during a perigee passage.
All video boards are powered off after the issuing of the WSVIDALLDN command,
which is marked by the orange line in the plot.}
\end{center}
\end{figure}
\end{landscape}

\begin{landscape}
\begin{figure}
\begin{center}
\includegraphics[width=1.2\textwidth]{deaa_on_fig2.eps}
\caption{Ten-sample running average behavior of 1DEICACU during a safe mode.
All video boards are powered off after the issuing of the WSPOW00000 command,
which is marked by the orange line in the plot.}
\end{center}
\end{figure}
\end{landscape}

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\newcommand{\tablecaptiontext}{TURN ON DEA B (realtime version)}
\input{deab_on.tab}

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