Markus Zolliker
4c5109e5a3
reading back the target does not work properly, because
a) the readback value might be delayed
b) there is no command to read back the target, SETP?1
is returning the working setpoint, which might be distinct
in case of a ramp
Change-Id: I0da2dbfc1a8ddbecbae6d0456ff64e008bc56336
Reviewed-on: https://forge.frm2.tum.de/review/c/secop/frappy/+/31983
Tested-by: Jenkins Automated Tests <pedersen+jenkins@frm2.tum.de>
Reviewed-by: Markus Zolliker <markus.zolliker@psi.ch>
109 lines
4.5 KiB
Python
109 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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default_settings = {'port': 7777, 'baudrate': 57600, 'parity': 'O', 'bytesize': 7}
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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(unit='K', min=0, max=1500))
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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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self.communicate(f'SETP {self.loop},{target};*OPC?')
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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 target
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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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