Antenna Control Computers (ACCs)

The Antenna Control Computers (ACCs) are the real-time computers that actually control the pointing and other hardware functions of each antenna. In order to meet the real-time observing requirements the ACCs run the pSOS operating system.

The ACC can be thought of as a `state machine' cycling around a loop of processing requests, setting up datasets and various events lines, reading back in large amounts of monitoring information, and returning this information to the central site. Currently, the usual time for a cycle is ten seconds (though this can be changed).

Normally the ACCs are left in the `remote' control mode so that they receive commands from the Legacy Server. However, the ACCs also have a `local' mode which allows the antennas to be controlled from the console terminal in the antenna pedestal rooms. Available options are:

xxxxxxx Local allows the antenna to be driven from the pedestal room
l 		 Local allows the antenna to be driven from the pedestal room


r 		 Remote allows the antenna to be driven remotely (i.e., from caobs)


on 		 Drives must be turned `on' before the antenna can be driven


off 		 Turns drives off


goto 		 Drive to a given azimuth and elevation


stop 		 Stops antenna drives


stow 		 Drives antenna to the stow position (Az=90, El=85)


park 		 Drives antenna to the park position (Az=90, El=90)

See on page for information on resetting ACCs.