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frappy/secop_psi/ls370res.py
Markus Zolliker 4c94580cb9 channel switcher for Lakeshore 370 with scanner 
- add a general channel switcher module
- change ls370res code from IOHandler to rwhandlers
+ fix an issue with the poller when io module is placed below
  using modules in cfg file

after this, IOHandler stuff may be removed from Frappy

Change-Id: I787101fc1e365ae3e0453bfe59291e2011a1fe53
Reviewed-on: https://forge.frm2.tum.de/review/c/sine2020/secop/playground/+/28512
Tested-by: Jenkins Automated Tests <pedersen+jenkins@frm2.tum.de>
Reviewed-by: Enrico Faulhaber <enrico.faulhaber@frm2.tum.de>
Reviewed-by: Markus Zolliker <markus.zolliker@psi.ch>
2022-05-25 07:47:32 +02:00

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#!/usr/bin/env python
# -*- coding: utf-8 -*-
# *****************************************************************************
# This program is free software; you can redistribute it and/or modify it under
# the terms of the GNU General Public License as published by the Free Software
# Foundation; either version 2 of the License, or (at your option) any later
# version.
#
# This program is distributed in the hope that it will be useful, but WITHOUT
# ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
# FOR A PARTICULAR PURPOSE. See the GNU General Public License for more
# details.
#
# You should have received a copy of the GNU General Public License along with
# this program; if not, write to the Free Software Foundation, Inc.,
# 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
#
# Module authors:
# Markus Zolliker <markus.zolliker@psi.ch>
# *****************************************************************************
"""LakeShore Model 370 resistance channel
implements autoscan and autorange by software.
when the autoscan or autorange button is pressed, the state is toggled,
and the hardware mode switched off again.
At startup, the configurable default mode is set, independent of
the hardware state.
"""
import time
from ast import literal_eval
import secop.io
from secop.datatypes import BoolType, EnumType, FloatRange, IntRange
from secop.lib import formatStatusBits
from secop.core import Done, Drivable, Parameter, Property, CommonReadHandler, CommonWriteHandler
from secop.io import HasIO
from secop_psi.channelswitcher import Channel, ChannelSwitcher
Status = Drivable.Status
STATUS_BIT_LABELS = 'CS_OVL VCM_OVL VMIX_OVL VDIF_OVL R_OVER R_UNDER T_OVER T_UNDER'.split()
class StringIO(secop.io.StringIO):
identification = [('*IDN?', 'LSCI,MODEL370,.*')]
wait_before = 0.05
class Switcher(HasIO, ChannelSwitcher):
value = Parameter(datatype=IntRange(1, 16))
target = Parameter(datatype=IntRange(1, 16))
use_common_delays = Parameter('use switch_delay and measure_delay instead of the channels pause and dwell',
BoolType(), readonly=False, default=False)
common_pause = Parameter('pause with common delays', FloatRange(3, 200, unit='s'), readonly=False, default=3)
ioClass = StringIO
fast_poll = 1
_measure_delay = None
_switch_delay = None
def startModule(self, start_events):
super().startModule(start_events)
# disable unused channels
for ch in range(1, 16):
if ch not in self._channels:
self.communicate('INSET %d,0,0,0,0,0;INSET?%d' % (ch, ch))
channelno, autoscan = literal_eval(self.communicate('SCAN?'))
if channelno in self._channels and self._channels[channelno].enabled:
if not autoscan:
return # nothing to do
else:
channelno = self.next_channel(channelno)
if channelno is None:
self.status = 'ERROR', 'no enabled channel'
return
self.communicate('SCAN %d,0;SCAN?' % channelno)
def doPoll(self):
"""poll buttons
and check autorange during filter time
"""
super().doPoll()
self._channels[self.target]._read_value() # check range or read
channelno, autoscan = literal_eval(self.communicate('SCAN?'))
if autoscan:
# pressed autoscan button: switch off HW autoscan and toggle soft autoscan
self.autoscan = not self.autoscan
self.communicate('SCAN %d,0;SCAN?' % self.value)
if channelno != self.value:
# channel changed by keyboard, do not yet return new channel
self.write_target(channelno)
chan = self._channels.get(channelno)
if chan is None:
channelno = self.next_channel(channelno)
if channelno is None:
raise ValueError('no channels enabled')
self.write_target(channelno)
chan = self._channels.get(self.value)
chan.read_autorange()
chan.fix_autorange() # check for toggled autorange button
return Done
def write_switch_delay(self, value):
self._switch_delay = value
return super().write_switch_delay(value)
def write_measure_delay(self, value):
self._measure_delay = value
return super().write_measure_delay(value)
def write_use_common_delays(self, value):
if value:
# use values from a previous change, instead of
# the values from the current channel
if self._measure_delay is not None:
self.measure_delay = self._measure_delay
if self._switch_delay is not None:
self.switch_delay = self._switch_delay
return value
def set_delays(self, chan):
if self.use_common_delays:
if chan.dwell != self.measure_delay:
chan.write_dwell(self.measure_delay)
if chan.pause != self.common_pause:
chan.write_pause(self.common_pause)
filter_ = max(0, self.switch_delay - self.common_pause)
if chan.filter != filter_:
chan.write_filter(filter_)
else:
# switch_delay and measure_delay is changing with channel
self.switch_delay = chan.pause + chan.filter
self.measure_delay = chan.dwell
def set_active_channel(self, chan):
self.communicate('SCAN %d,0;SCAN?' % chan.channel)
chan._last_range_change = time.monotonic()
self.set_delays(chan)
class ResChannel(Channel):
"""temperature channel on Lakeshore 370"""
RES_RANGE = {key: i+1 for i, key in list(
enumerate(mag % val for mag in ['%gmOhm', '%gOhm', '%gkOhm', '%gMOhm']
for val in [2, 6.32, 20, 63.2, 200, 632]))[:-2]}
CUR_RANGE = {key: i + 1 for i, key in list(
enumerate(mag % val for mag in ['%gpA', '%gnA', '%guA', '%gmA']
for val in [1, 3.16, 10, 31.6, 100, 316]))[:-2]}
VOLT_RANGE = {key: i + 1 for i, key in list(
enumerate(mag % val for mag in ['%guV', '%gmV']
for val in [2, 6.32, 20, 63.2, 200, 632]))}
RES_SCALE = [2 * 10 ** (0.5 * i) for i in range(-7, 16)] # RES_SCALE[0] is not used
MAX_RNG = len(RES_SCALE) - 1
channel = Property('the Lakeshore channel', datatype=IntRange(1, 16), export=False)
value = Parameter(datatype=FloatRange(unit='Ohm'))
pollinterval = Parameter(visibility=3, default=1)
range = Parameter('reading range', readonly=False,
datatype=EnumType(**RES_RANGE))
minrange = Parameter('minimum range for software autorange', readonly=False, default=1,
datatype=EnumType(**RES_RANGE))
autorange = Parameter('autorange', datatype=BoolType(),
readonly=False, default=1)
iexc = Parameter('current excitation', datatype=EnumType(off=0, **CUR_RANGE), readonly=False)
vexc = Parameter('voltage excitation', datatype=EnumType(off=0, **VOLT_RANGE), readonly=False)
enabled = Parameter('is this channel enabled?', datatype=BoolType(), readonly=False)
pause = Parameter('pause after channel change', datatype=FloatRange(3, 60, unit='s'), readonly=False)
dwell = Parameter('dwell time with autoscan', datatype=FloatRange(1, 200, unit='s'), readonly=False)
filter = Parameter('filter time', datatype=FloatRange(1, 200, unit='s'), readonly=False)
_toggle_autorange = 'init'
_prev_rdgrng = (1, 1) # last read values for icur and exc
_last_range_change = 0
rdgrng_params = 'range', 'iexc', 'vexc'
inset_params = 'enabled', 'pause', 'dwell'
def communicate(self, command):
return self.switcher.communicate(command)
def read_status(self):
if not self.enabled:
return [self.Status.DISABLED, 'disabled']
if not self.channel == self.switcher.value == self.switcher.target:
return Done
result = int(self.communicate('RDGST?%d' % self.channel))
result &= 0x37 # mask T_OVER and T_UNDER (change this when implementing temperatures instead of resistivities)
statustext = ' '.join(formatStatusBits(result, STATUS_BIT_LABELS))
if statustext:
return [self.Status.ERROR, statustext]
return [self.Status.IDLE, '']
def _read_value(self):
"""read value, without update"""
now = time.monotonic()
if now + 0.5 < max(self._last_range_change, self.switcher._start_switch) + self.pause:
return None
result = self.communicate('RDGR?%d' % self.channel)
result = float(result)
if self.autorange:
self.fix_autorange()
if now + 0.5 > self._last_range_change + self.pause:
rng = int(max(self.minrange, self.range)) # convert from enum to int
if self.status[1] == '':
if abs(result) > self.RES_SCALE[rng]:
if rng < 22:
rng += 1
else:
lim = 0.2
while rng > self.minrange and abs(result) < lim * self.RES_SCALE[rng]:
rng -= 1
lim -= 0.05 # not more than 4 steps at once
# effectively: <0.16 %: 4 steps, <1%: 3 steps, <5%: 2 steps, <20%: 1 step
elif rng < self.MAX_RNG:
rng = min(self.MAX_RNG, rng + 1)
if rng != self.range:
self.write_range(rng)
self._last_range_change = now
return result
def read_value(self):
if self.channel == self.switcher.value == self.switcher.target:
return self._read_value()
return Done # return previous value
def is_switching(self, now, last_switch, switch_delay):
last_switch = max(last_switch, self._last_range_change)
if now + 0.5 > last_switch + self.pause:
self._read_value() # adjust range only
return super().is_switching(now, last_switch, switch_delay)
@CommonReadHandler(rdgrng_params)
def read_rdgrng(self):
iscur, exc, rng, autorange, excoff = literal_eval(
self.communicate('RDGRNG?%d' % self.channel))
self._prev_rdgrng = iscur, exc
if autorange: # pressed autorange button
if not self._toggle_autorange:
self._toggle_autorange = True
iexc = 0 if excoff or not iscur else exc
vexc = 0 if excoff or iscur else exc
if (rng, iexc, vexc) != (self.range, self.iexc, self.vexc):
self._last_range_change = time.monotonic()
self.range, self.iexc, self.vexc = rng, iexc, vexc
@CommonWriteHandler(rdgrng_params)
def write_rdgrng(self, change):
self.read_range() # make sure autorange is handled
if 'vexc' in change: # in case vext is changed, do not consider iexc
change['iexc'] = 0
if change['iexc'] != 0: # we need '!= 0' here, as bool(enum) is always True!
iscur = 1
exc = change['iexc']
excoff = 0
elif change['vexc'] != 0: # we need '!= 0' here, as bool(enum) is always True!
iscur = 0
exc = change['vexc']
excoff = 0
else:
iscur, exc = self._prev_rdgrng # set to last read values
excoff = 1
rng = change['range']
if self.autorange:
if rng < self.minrange:
rng = self.minrange
self.communicate('RDGRNG %d,%d,%d,%d,%d,%d;*OPC?' % (
self.channel, iscur, exc, rng, 0, excoff))
self.read_range()
def fix_autorange(self):
if self._toggle_autorange:
if self._toggle_autorange == 'init':
self.write_autorange(True)
else:
self.write_autorange(not self.autorange)
self._toggle_autorange = False
@CommonReadHandler(inset_params)
def read_inset(self):
# ignore curve no and temperature coefficient
enabled, dwell, pause, _, _ = literal_eval(
self.communicate('INSET?%d' % self.channel))
self.enabled = enabled
self.dwell = dwell
self.pause = pause
@CommonWriteHandler(inset_params)
def write_inset(self, change):
_, _, _, curve, tempco = literal_eval(
self.communicate('INSET?%d' % self.channel))
self.enabled, self.dwell, self.pause, _, _ = literal_eval(
self.communicate('INSET %d,%d,%d,%d,%d,%d;INSET?%d' % (
self.channel, change['enabled'], change['dwell'], change['pause'], curve, tempco,
self.channel)))
if 'enabled' in change and change['enabled']:
# switch to enabled channel
self.switcher.write_target(self.channel)
elif self.switcher.target == self.channel:
self.switcher.set_delays(self)
def read_filter(self):
on, settle, _ = literal_eval(self.communicate('FILTER?%d' % self.channel))
return settle if on else 0
def write_filter(self, value):
on = 1 if value else 0
value = max(1, value)
on, settle, _ = literal_eval(self.communicate(
'FILTER %d,%d,%g,80;FILTER?%d' % (self.channel, on, value, self.channel)))
if not on:
settle = 0
return settle
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