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Create phase_down.py #232

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60 changes: 60 additions & 0 deletions observation/phase_down.py
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#!/usr/bin/env python
#
# Reset the delay adjustments and CBF F-engine gains to zero.

import time

import numpy as np
import katpoint
from katcorelib.observe import (standard_script_options, verify_and_connect,
collect_targets, start_session, user_logger,
SessionSDP)

class NoTargetsUpError(Exception):
"""No targets are above the horizon at the start of the observation."""

# Set up standard script options
usage = "%prog"
description = 'Reset all the delays and phases to default.'
parser = standard_script_options(usage, description)
# Add experiment-specific options

# Set default value for any option (both standard and experiment-specific options)
parser.set_defaults(observer='comm_test', nd_params='off', project_id='COMMTEST',
description='Phase-up observation that sets the F-engine weights')
# Parse the command line
opts, args = parser.parse_args()

# Set of targets with flux models
J1934 = 'PKS 1934-63 | J1939-6342, radec, 19:39:25.03, -63:42:45.7, (200.0 12000.0 -11.11 7.777 -1.231)'
J0408 = 'PKS 0408-65 | J0408-6545, radec, 4:08:20.38, -65:45:09.1, (800.0 8400.0 -3.708 3.807 -0.7202)'
J1331 = '3C286 | J1331+3030, radec, 13:31:08.29, +30:30:33.0,(800.0 43200.0 0.956 0.584 -0.1644)'

observation_sources = katpoint.Catalogue(antenna=kat.sources.antenna)
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@ajoubertza ajoubertza Jul 31, 2017

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The kat object hasn't been assigned yet. Looks like this block needs to move down, after line 41.

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@ludwigschwardt ludwigschwardt Jul 31, 2017

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As below, I would suggest to follow calibrate_delays.py as a template. We have removed these explicit sources in the code and replaced them with the three_calib.csv file in the instruction set. The whole catalogue construction also moves down to after verify_and_connect as @ajoubertza suggests. I also pick only a single source as opposed to looping through a list containing one source.

observation_sources.add(J1934)
observation_sources.add(J0408)
observation_sources.add(J1331)

if len(observation_sources.filter(el_limit_deg=opts.horizon)) == 0:
raise NoTargetsUpError("No targets are currently visible - please re-run the script later")

with verify_and_connect(opts) as kat:
with start_session(kat, **vars(opts)) as session:
session.standard_setup(**vars(opts))
session.cbf.correlator.req.capture_start()
channels = 32768 if session.product.endswith('32k') else 4096
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@ajoubertza ajoubertza Jul 31, 2017

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I know this check is used in other scripts, but it isn't very robust. E.g. for a user product like c856M32k4s or bec856M32kram. There is a CBF sensor that gives the number of channels, so suggest that is used instead. Think you can use it like this: channels = session.cbf.fengine.sensor.n_chans

@ludwigschwardt, please confirm that is the correct way to use the SessionCBFStream object.

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@ludwigschwardt ludwigschwardt Jul 31, 2017

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Indeed. My best suggestions would be to look at calibrate_delays.py as that is the most up-to-date cal/cbf-interacting script. There is a function that you can copy (and which should move into CaptureSession now that there is more than one user :-)):

# Default F-engine gain as a function of number of channels
DEFAULT_GAIN = {4096: 200, 32768: 4000}

def set_fengine_gain(session, gain):
    """Set F-engine gain to *gain* if positive, or automatic default if 0."""
    if session.kat.dry_run:
        gain = -1
    # Obtain default gain based on channel count if none specified
    if gain == 0:
        num_channels = session.cbf.fengine.sensor.n_chans.get_value()
        gain = DEFAULT_GAIN.get(num_channels, -1)
    if gain > 0:
        user_logger.info("Setting F-engine gains to %d" % (gain,))
        for inp in session.cbf.fengine.inputs:
            session.cbf.fengine.req.gain(inp, gain)

if channels == 4096:
default_gain = 200
elif channels == 32768:
default_gain = 4000
user_logger.info("Resetting F-engine gains to %g", default_gain)
for inp in session.cbf.fengine.inputs:
session.cbf.fengine.req.gain(inp, default_gain)
user_logger.info("Resetting delay adjustments to zero")
session.cbf.req.adjust_all_delays()

track_duration = 24
for target in [observation_sources.sort('el').targets[-1]]:
user_logger.info("Initiating %g-second track on target '%s' to validate reset",
track_duration, target.name)
session.track(target, duration=track_duration, announce=False)