Intro

    The pointing program (actually programs) is run on the pnt vme crate (motorola 167 boards). They are written in C for the vxWorks operating system.

• pntMProg.c  - master pointing program.
  
• runs on the pnt cpu
• talks to the outside world via messages
• controls the other programs that make up the pointing system
• It is closely coupled with pntXform since they both run on the same cpu (vxWorks memory can be global on a cpu).
• a semaphore is used to synchronize the communications of these two through a common memory area.
• pntXform takes care of providing timestamped encoder values for the various devices (vertex,turret, tiedowns)
• pntMProg does the communications with the outside world. It also sends the non time critical commands (doit it now stuff) tothe various devices.
  
• pntXForm.c - performs the pointing transformations (ra,dec to az,za) once a second.
• runs on pnt cpu
• talks to pntMProg.c via a common communications area (vxWorks memory) and a semaphore to synchronize access to area
• runs on a 1 second tick cycle. Every second it wakes up and:
• checks for new points for vertex, turret, tie (in that order)
  
• vertex: Transforms ra,dec (or whatever higher level coordinate system) to az,za once a second
  
• It does this two seconds in the future.
• offsets, rates are added at this point
  
• sends time the stamped az,za positions  to the agcProg (on pntp1 cpu) once a second.
• The agcProg sends these to the the vertex control computer
• They are sent 1 to 2seconds in the future
• turret, tiedown can be command to do patterns.. ramps, sinewaves, etc
• these are computed here and then sent to the devices.
  
• agcProg.c - controls the vertex devices: az, ch,, dome via the control computers in the vertex shelter.
• agcOProg.c - real time portion of agcProg.
• loops taking requests off a queue and sending to the vertex once a second.
• both run on the pntp1 cpu in the pnt crate
• agcProg receives commands from pntMProg to forward to the  vertex system
• receives time stamped az,za positions for tracking from pntXform once a second
• regular commands are sent to vertex when they are received
• timestamped tracking positions are pushed onto a fifo for agcOProg
  
• agcOProg takes data for the fifo and sends to vertex when ready
• The split in programs is so that agcOProg never waits on i/o  and runs at a higher priority than agcProg
  
• send commands to vertex system via a dedicated ethernet.
• ttProg.c - controls the turret
• runs on pntp2.
• receives requests from pntMProg and pntXform
  
• sends info to little star master  (below pnt vme crate) using rs422->rs485 conveter (check this).
• The master sends info to little star in the rotary floor room to control the floor.
• tieProg.c - controls the tiedowns
  
• runs on pntp3
• receives requests from pntMProg and pntXform
  
• sends comands out the rs232/422 port to the little start master for the tiedowns.
• The little start master forwards the info to the 3 little stars under the bowl at each tiedown
• lrMon.c - grabs the laser ranging data and computes the average platform height.
• runs on pntp3
  
• provides info to pntMProg to decide how to move the tiedowns to keep the platform at the correct height.
  

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