Bases: KPFTranslatorFunction
Set the position of the tip tilt mirror.
This should only be used in an engineering context. To control the position
of a star, set the CURRENT_BASE or PIX_TARGET keywords as appropriate, e.g.
via the kpf.fiu.SetTipTiltTargetPixel
translator module function.
Parameters: |
-
x
(float )
–
The desired X position (TTXVAX).
-
y
(float )
–
The desired Y position (TTYVAX).
|
KTL Keywords Used:
kpffiu.TTXVAX
kpffiu.TTYVAX
Source code in kpf/fiu/SetTipTiltPosition.py
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62 | class SetTipTiltPosition(KPFTranslatorFunction):
'''Set the position of the tip tilt mirror.
This should only be used in an engineering context. To control the position
of a star, set the CURRENT_BASE or PIX_TARGET keywords as appropriate, e.g.
via the `kpf.fiu.SetTipTiltTargetPixel` translator module function.
Args:
x (float): The desired X position (TTXVAX).
y (float): The desired Y position (TTYVAX).
KTL Keywords Used:
- `kpffiu.TTXVAX`
- `kpffiu.TTYVAX`
'''
@classmethod
def pre_condition(cls, args, logger, cfg):
check_input(args, 'x')
check_input(args, 'y')
@classmethod
def perform(cls, args, logger, cfg):
kpffiu = ktl.cache('kpffiu')
kpffiu['TTXVAX'].write(args.get('x'))
kpffiu['TTYVAX'].write(args.get('y'))
time_shim = cfg.getfloat('times', 'tip_tilt_move_time', fallback=0.1)
time.sleep(time_shim)
@classmethod
def post_condition(cls, args, logger, cfg):
kpffiu = ktl.cache('kpffiu')
timeout = cfg.getfloat('times', 'tip_tilt_move_time', fallback=0.1)
tol = cfg.getfloat('tolerances', 'tip_tilt_move_tolerance', fallback=0.1)
xdest = args.get('x')
ydest = args.get('y')
expr = (f'($kpffiu.TTXVAX > {xdest-tol}) and '\
f'($kpffiu.TTXVAX < {xdest+tol})')
successx = ktl.waitFor(expr, timeout=timeout)
if successx is not True:
raise FailedToReachDestination(kpffiu['TTXVAX'].read(), xdest)
expr = (f'($kpffiu.TTYVAX > {ydest-tol}) and '\
f'($kpffiu.TTYVAX < {ydest+tol})')
successy = ktl.waitFor(expr, timeout=timeout)
if successy is not True:
raise FailedToReachDestination(kpffiu['TTYVAX'].read(), ydest)
@classmethod
def add_cmdline_args(cls, parser, cfg=None):
parser.add_argument('x', type=float,
help="X position of the tip tilt mirror (TTXVAX)")
parser.add_argument('y', type=float,
help="X position of the tip tilt mirror (TTYVAX)")
return super().add_cmdline_args(parser, cfg)
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