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#
# This file is part of the PyMeasure package.
#
# Copyright (c) 2013-2024 PyMeasure Developers
#
# Permission is hereby granted, free of charge, to any person obtaining a copy
# of this software and associated documentation files (the "Software"), to deal
# in the Software without restriction, including without limitation the rights
# to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
# copies of the Software, and to permit persons to whom the Software is
# furnished to do so, subject to the following conditions:
#
# The above copyright notice and this permission notice shall be included in
# all copies or substantial portions of the Software.
#
# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
# FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
# AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
# LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
# OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
# THE SOFTWARE.
#
from re import compile
from pymeasure.instruments import Channel, Instrument
from pymeasure.instruments.validators import strict_discrete_set
class RelayChannel(Channel):
"""
Settings of the optionally included setpoint relay.
The relay is energized either below or above the setpoint depending on the
'direction' property. The relay is de-energized when the reset value is
crossed in the opposite direction.
Note that device by default uses an auto hysteresis setting of 10% of the
setpoint value that overwrites the current reset value whenever the setpoint
value or direction is changed. If other hysteresis value than 10% is
required, first set the setpoint value and direction before setting the
reset value.
"""
status = Channel.measurement(
"SS{ch}?",
"""Get the setpoint relay status""",
values={True: "SET", False: "CLEAR"},
)
setpoint = Channel.control(
"SP{ch}?", "SP{ch}!%s",
"""Control the relay switch setpoint""",
check_set_errors=True,
)
resetpoint = Channel.control(
"SH{ch}?", "SH{ch}!%s",
"""Control the relay switch off value""",
check_set_errors=True,
)
direction = Channel.control(
"SD{ch}?", "SD{ch}!%s",
"""Control the switching direction""",
validator=strict_discrete_set,
values=["ABOVE", "BELOW"],
check_set_errors=True,
)
class MKSInstrument(Instrument):
"""Abstract MKS Instrument
Connection to the device is made through an RS232/RS485 serial connection.
The communication protocol of these devices is as follows:
Query: '@<aaa><Command>?;FF' with the response '@<aaa>ACK<Response>;FF'
Set command: '@<aaa><Command>!<parameter>;FF' with the response '@<aaa>ACK<Response>;FF'
Above <aaa> is an address from 001 to 254 which can be specified upon
initialization. Since ';FF' is not supported by pyvisa as terminator this
class overloads the device communication methods.
:param adapter: pyvisa resource name of the instrument or adapter instance
:param string name: The name of the instrument.
:param address: device address included in every message to the instrument
(default=253)
:param kwargs: Any valid key-word argument for Instrument
"""
def __init__(self, adapter, name="MKS Instrument", address=253, **kwargs):
super().__init__(
adapter,
name,
includeSCPI=False,
read_termination=";", # in reality its ";FF"
# which is, however, invalid for pyvisa. Therefore extra bytes have to
# be read in the read() method and the terminators are hardcoded here.
write_termination=";FF",
**kwargs
)
self.address = address
# compiled regular expression for finding numerical values in reply strings
self._re_response = compile(fr"@{self.address:03d}(?P<ack>ACK)?(?P<msg>.*)")
def _extract_reply(self, reply):
""" preprocess_reply function which tries to extract <Response> from
'@<aaa>ACK<Response>;FF'. If <Response> can not be identified the orignal string
is returned.
:param reply: reply string
:returns: string with only the response, or the original string
"""
rvalue = self._re_response.search(reply)
if rvalue:
return rvalue.group('msg')
return reply
def _prepend_address(self, cmd):
"""
create command string by including the device address
"""
return f"@{self.address:03d}{cmd}"
def _check_extra_termination(self):
"""
Check the read termination to correspond to the protocol
"""
t = super().read_bytes(2) # read extra termination chars 'FF'
if t != b'FF':
raise ValueError(f"unexpected termination string received {t}")
def read(self):
"""
Reads from the instrument including the correct termination characters
"""
ret = super().read()
self._check_extra_termination()
return self._extract_reply(ret)
def write(self, command):
"""
Write to the instrument including the device address.
:param command: command string to be sent to the instrument
"""
super().write(self._prepend_address(command))
def check_set_errors(self):
"""
Check reply string for acknowledgement string.
"""
ret = super().read() # use super read to get raw reply
reply = self._re_response.search(ret)
if reply:
if reply.group('ack') == 'ACK':
self._check_extra_termination()
return []
# no valid acknowledgement message found
raise ValueError(f"invalid reply '{ret}' found in check_errors")
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