doc: Document the Apogee Lockout setting

[fw/altos] / doc / altusmetrum.xsl

diff --git a/doc/altusmetrum.xsl b/doc/altusmetrum.xsl
index d3d1f72a9e1228e9536c9610a4a9a9f4387f6e7f..39b3998a5154f35e35fa9042b56222b79340e736 100644 (file)
--- a/doc/altusmetrum.xsl
+++ b/doc/altusmetrum.xsl
@@ -1539,10 +1539,13 @@ NAR #88757, TRA #12200
         first five seconds of operation.
       </para>
       <para>
-        At power on, you will hear three beeps or see three flashes
-        (“S” in Morse code for start up) and then a pause while
-        the altimeter completes initialization and self test, and decides 
-       which mode to enter next.
+        At power on, the altimeter will beep out the battery voltage
+        to the nearest tenth of a volt.  Each digit is represented by
+        a sequence of short “dit” beeps, with a pause between
+        digits. A zero digit is represented with one long “dah”
+        beep. Then there will be a short pause while the altimeter
+        completes initialization and self test, and decides which mode
+        to enter next.
       </para>
       <para>
        Here's a short summary of all of the modes and the beeping (or
@@ -1570,7 +1573,7 @@ NAR #88757, TRA #12200
              <row>
                <entry>Startup</entry>
                <entry>S</entry>
-               <entry>dit dit dit</entry>
+               <entry>battery voltage in decivolts</entry>
                <entry>
                  <para>
                    Calibrating sensors, detecting orientation.
@@ -2180,6 +2183,20 @@ NAR #88757, TRA #12200
           way quite happily, including Keith's successful L3 cert.
         </para>
       </section>
+      <section>
+       <title>Apogee Lockout</title>
+       <para>
+         Apogee lockout is the number of seconds after boost where
+         the flight computer will not fire the apogee charge, even if
+         the rocket appears to be at apogee. This is often called
+         'Mach Delay', as it is intended to prevent a flight computer
+         from unintentionally firing apogee charges due to the pressure
+         spike that occurrs across a mach transition. Altus Metrum
+         flight computers include a Kalman filter which is not fooled
+         by this sharp pressure increase, and so this setting should
+         be left at the default value of zero to disable it.
+       </para>
+      </section>
       <section>
         <title>Main Deployment Altitude</title>
         <para>