#!/bin/csh -f
#+
# rotang -- set/show physical DEIMOS rotator angle
#
# Purpose:
#	With no arguments, show the current DEIMOS rotator angle in the
#	DEIMOS coordinate system (which is approximately 90 deg off of
#	the rotator angle shown on FACSUM).  With one numeric argument, set the
#	rotator to the specified physical rotator angle.
#
# Usage:
#	rotang [angle]
# 
# Arguments:
#	angle = rotator angle [degrees]
# 
# Output:
#	Current or new rotator angle [degrees]
# 
# Restrictions:
#	- DEIMOS rotation must be enabled for moves to work
#	- DEIMOS must be under observer control, not DCS control
# 
# Exit values:
#	 0 = normal completion
#	 1 = wrong number of arguments
#
# Example:
#	1) Show the current rotator angle
#		rotang
#
#	2) Set the rotator angle to 123.45 (DEIMOS physical system):
#		rotang 123.45
#-
# Modification history:
#	2003-Aug-25	GDW	Original version
#-----------------------------------------------------------------------

set buf = $0
set cmd = $buf:t
set usage = "Usage: $cmd [angle]"

# verify args...
if ( $#argv > 1 ) then
  printf "$usage\n"
  exit 1
endif

# take appropriate action...
if ( $#argv == 0 ) then
    show -s deirot -terse rotatval
    exit
else

    # validate argument...
    set angle = $1
    is_float $angle > /dev/null
    if ( $status != 0 ) then
	printf "$usage\n"
	exit 1
    endif

    # cxheck whether instrument rotator is locked...
    set rotatlck=`show -s deirot -terse rotatlck`
    if( $status ) then
	printf "ERROR: can't read ROTATLCK keyword\n"
	exit 1
    endif
    if( "$rotatlck" != "UNLOCKED" ) then
	printf "ERROR: DEIMOS rotation system is locked\n"
	exit 1
    endif

    # check for Pos mode...
    set rotatmod = `show -s deirot -terse rotatmod`
    if( $status ) then
	printf "ERROR: can't read ROTATMOD keyword\n"
	exit 1
    endif
    if( "$rotatmod" != "Pos" ) then
	printf "ERROR: DEIMOS rotator is not is Pos mode\n"
	exit 1
    endif

    # move the beast...
    modify -s deirot rotatval=$angle
    if( $status ) then
	printf "ERROR moving rotator\n"
	exit 1
    endif

endif
exit