#    This is the channel Pre Trigger Size register  0x1n38



    for {set i 0} {$i < $NumChans} {incr i} {
        variable Ch$i.PreTrig 0
    }

proc GetPreTrig {} {
    variable NumChans

    for {set i 0} {$i < $NumChans} {incr i} {
        variable Ch$i.PreTrig
        set Ch$i.PreTrig [expr [ReadRegister Ch$i.PreTrig] * 2]
    }
}

proc SetPreTrig {w} {
    variable NumChans

      for {set i 0} {$i < $NumChans} {incr i} {

         if {$w < $NumChans && $w != $i} {continue}

         variable Ch$i.PreTrig
         WriteRegister Ch$i.PreTrig [expr [set Ch$i.PreTrig] / 2]
      }

}

    proc SavePreTrig {} {
        variable NumChans

      for {set i 0} {$i < $NumChans} {incr i} {

           DBSetValue Ch$i.PreTrig [ReadRegister Ch$i.PreTrig]
      }
    }

    proc RestPreTrig {} {
        variable NumChans

      for {set i 0} {$i < $NumChans} {incr i} {

           variable Ch$i.PreTrig
           set Ch$i.PreTrig  [expr [DBGetValue Ch$i.PreTrig] * 2]
           WriteRegister Ch$i.PreTrig [expr [set Ch$i.PreTrig] / 2]
      }

    }

proc DrawPreTrig {} {
    variable NumChans
    variable Name

   set html ""

   append html  "<p align=center>"
   append html  "<table cellpadding=0 cellspacing=0 border=1>"

   append html "<tr>"
   append html  "<td  align=center width=10%>Channel</td>"
   append html  "<td  align=center width=90%>Channel n Pre Trigger Size (samples)</td>"
   append html  "</tr>"

for {set i 0} {$i < $NumChans} {incr i} {

   append html "<tr>"
   append html "<td align=center width=10%>$i</td>"
   append html "<td align=center width=90%><div id=\"Offset$i\"></div>&nbsp;</td>"
   append html  "</tr>"
}
   append html  "</table>"

   append html "<script>"

   append html "SliderID('PreTrig');"

for {set i 0} {$i < $NumChans} {incr i} {
   append html "SelectSlider($i); SetSlider(0,2046,25,120);"
   append html "MakeSlider(document.[set Name], $i, [set ::[set Name]::Ch$i.PreTrig]);"
}

   append html "</script>"

   append html  "</p>"

   return $html
}