Source code for caproto.ioc_examples.decay

#!/usr/bin/env python3
from caproto.server import pvproperty, PVGroup, ioc_arg_parser, run
import numpy as np
import time
from textwrap import dedent

[docs]class Decay(PVGroup): """ Simulates an exponential decay to a set point. Follows :math:`T_{output} = T_{var} exp^{-(t - t_0)/K} + T_{setpoint}` The default prefix is `decay:` Readonly PVs ------------ I -> the current value done -> if the current value is 'close' to the setpoint Control PVs ----------- SP -> where to go K -> the decay constant Tvar -> the scale of the initial excursion """ def _compute_done(self): gap = np.abs(self.readback.value - self.setpoint.value) gap_i = np.abs(self.setpoint.value - self.Tvar.value) # get with in 5% return (gap / gap_i) < .05 def __init__(self, *args, **kwargs): super().__init__(*args, **kwargs) self._T0 = time.monotonic() readback = pvproperty(value=0, dtype=float, read_only=True, name='I', mock_record='ai') done = pvproperty(value=0, dtype=float, read_only=True, mock_record='ai') setpoint = pvproperty(value=100, dtype=float, name='SP') K = pvproperty(value=10, dtype=float) Tvar = pvproperty(value=10, dtype=float) @readback.scan(period=.1, use_scan_field=True) async def readback(self, instance, async_lib): def t_rbv(T0, setpoint, K, Tvar,): t = time.monotonic() return ((Tvar * np.exp(-(t - self._T0) / K)) + setpoint) T = t_rbv(T0=self._T0, **{k: getattr(self, k).value for k in ['setpoint', 'K', 'Tvar']}) await instance.write(value=T) done = self._compute_done() if self.done.value != done: await self.done.write(done) @setpoint.putter async def setpoint(self, instance, value): self._T0 = time.monotonic() return value
if __name__ == '__main__': ioc_options, run_options = ioc_arg_parser( default_prefix='decay:', desc=dedent(Decay.__doc__)) ioc = Decay(**ioc_options) run(ioc.pvdb, **run_options)