add tutorial for Berlin hands-on workshop + improve the documentation (hints for structure welcome) + remove 'optional' parameter property (is not yet used - should not appear in doc) + added test property in frappy_demo.cryo alters Parameter class ('test' property appears in Parameter doc) Change-Id: I3ea08f955a92f72451fd23a5ff00d1185c7fb00e
111 lines
4.5 KiB
Python
111 lines
4.5 KiB
Python
#!/usr/bin/env python
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# -*- coding: utf-8 -*-
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# *****************************************************************************
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# This program is free software; you can redistribute it and/or modify it under
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# the terms of the GNU General Public License as published by the Free Software
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# Foundation; either version 2 of the License, or (at your option) any later
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# version.
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#
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# This program is distributed in the hope that it will be useful, but WITHOUT
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# ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
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# FOR A PARTICULAR PURPOSE. See the GNU General Public License for more
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# details.
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#
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# You should have received a copy of the GNU General Public License along with
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# this program; if not, write to the Free Software Foundation, Inc.,
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# 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
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#
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# Module authors:
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# Markus Zolliker <markus.zolliker@psi.ch>
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# *****************************************************************************
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"""LakeShore demo
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demo example for tutorial
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"""
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from frappy.core import Readable, Parameter, FloatRange, HasIO, StringIO, Property, StringType, \
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IDLE, BUSY, WARN, ERROR, Drivable, IntRange
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class LakeshoreIO(StringIO):
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wait_before = 0.05 # Lakeshore requires a wait time of 50 ms between commands
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# Lakeshore commands (see manual)
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# '*IDN?' is sent on connect, and the reply is checked to match the regexp 'LSCI,.*'
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identification = [('*IDN?', 'LSCI,.*')]
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class TemperatureSensor(HasIO, Readable):
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"""a temperature sensor (generic for different models)"""
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# internal property to configure the channel
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channel = Property('the Lakeshore channel', datatype=StringType())
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# 0, 1500 is the allowed range by the LakeShore controller
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# this range should be further restricted in the configuration (see below)
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value = Parameter(datatype=FloatRange(0, 1500, unit='K'))
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def read_value(self):
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# the communicate method sends a command and returns the reply
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reply = self.communicate(f'KRDG?{self.channel}')
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return float(reply)
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def read_status(self):
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code = int(self.communicate(f'RDGST?{self.channel}'))
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if code >= 128:
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text = 'units overrange'
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elif code >= 64:
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text = 'units zero'
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elif code >= 32:
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text = 'temperature overrange'
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elif code >= 16:
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text = 'temperature underrange'
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elif code % 2:
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# ignore 'old reading', as this may happen in normal operation
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text = 'invalid reading'
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else:
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return IDLE, ''
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return ERROR, text
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class TemperatureLoop(TemperatureSensor, Drivable):
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# lakeshore loop number to be used for this module
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loop = Property('lakeshore loop', IntRange(1, 2), default=1)
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target = Parameter(datatype=FloatRange(min=0, max=1500, unit='K'))
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heater_range = Property('heater power range', IntRange(0, 5)) # max. 3 on LakeShore 336
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tolerance = Parameter('convergence criterion', FloatRange(0), default=0.1, readonly = False)
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_driving = False
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def write_target(self, target):
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# reactivate heater in case it was switched off
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# the command has to be changed in case of model 340 to f'RANGE {self.heater_range};RANGE?'
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self.communicate(f'RANGE {self.loop},{self.heater_range};RANGE?{self.loop}')
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reply = self.communicate(f'SETP {self.loop},{target};SETP? {self.loop}')
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self._driving = True
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# Setting the status attribute triggers an update message for the SECoP status
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# parameter. This has to be done before returning from this method!
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self.status = BUSY, 'target changed'
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return float(reply)
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def read_target(self):
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return float(self.communicate(f'SETP?{self.loop}'))
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def read_status(self):
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code = int(self.communicate(f'RDGST?{self.channel}'))
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if code >= 128:
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text = 'units overrange'
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elif code >= 64:
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text = 'units zero'
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elif code >= 32:
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text = 'temperature overrange'
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elif code >= 16:
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text = 'temperature underrange'
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elif code % 2:
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# ignore 'old reading', as this may happen in normal operation
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text = 'invalid reading'
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elif abs(self.target - self.value) > self.tolerance:
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if self._driving:
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return BUSY, 'approaching setpoint'
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return WARN, 'temperature out of tolerance'
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else: # within tolerance: simple convergence criterion
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self._driving = False
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return IDLE, ''
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return ERROR, text
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