1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
|
#
# 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.
#
import ctypes
import logging
from pymeasure.instruments import Instrument
log = logging.getLogger(__name__)
log.addHandler(logging.NullHandler())
c_uint8 = ctypes.c_uint8
c_uint16 = ctypes.c_uint16
c_uint32 = ctypes.c_uint32
class StatusBitsBase(ctypes.BigEndianStructure):
"""
A bitfield structure containing the assignments for the status decoding
"""
_pack_ = 1
_get_process_ = {}
# decoder functions
# decimal to BCD & BCD to decimal conversion copied from
# https://pymodbus.readthedocs.io/en/latest/source/example/bcd_payload.html
@staticmethod
def _convert_from_bcd(bcd):
"""Converts a bcd value to a decimal value
:param value: The value to unpack from bcd
:returns: The number in decimal form
"""
place, decimal = 1, 0
while bcd > 0:
nibble = bcd & 0xF
decimal += nibble * place
bcd >>= 4
place *= 10
return decimal
@staticmethod
def _convert_to_bcd(decimal):
"""Converts a decimal value to a bcd value
:param value: The decimal value to to pack into bcd
:returns: The number in bcd form
"""
place, bcd = 0, 0
while decimal > 0:
nibble = decimal % 10
bcd += nibble << place
decimal //= 10
place += 4
return bcd
def __str__(self):
"""
Returns a pretty formatted string showing the status of the instrument
"""
ret_str = ""
for field in self._fields_:
ret_str = ret_str + f"{field[0]}: {hex(getattr(self, field[0]))}\n"
return ret_str
def __getattribute__(self, name):
val = super().__getattribute__(name)
if name == "fields":
return val
if name in self.fields():
process = super().__getattribute__('_get_process_')
if name in process:
val = process[name](val)
return val
def fields(self):
return [desc[0] for desc in super().__getattribute__('_fields_')]
class HPLegacyInstrument(Instrument):
"""
Class for legacy HP instruments from the era before SPCI, based on `pymeasure.Instrument`
"""
status_desc = StatusBitsBase # To be overriden by subclasses
def __init__(self, adapter, name="HP legacy instrument", **kwargs):
super().__init__(
adapter, name,
includeSCPI=False,
**kwargs,
)
self.status_bytes_count = ctypes.sizeof(self.status_desc)
self.status_bits = self.status_desc
log.info(f"Initializing {self.name}")
def write(self, command):
if command == "B":
self.write_bytes(b"B")
else:
super().write(command)
def values(self, command, **kwargs):
if command == "B":
self.write_bytes(b"B")
return self.read_bytes(-1, **kwargs)
else:
return super().values(command, **kwargs)
@property
def status(self):
"""
Get an object representing the current status of the unit.
"""
self.write_bytes(b"B")
reply = bytearray(self.read_bytes(self.status_bytes_count))
return self.status_bits.from_buffer(reply)
def GPIB_trigger(self):
"""
Initate trigger via low-level GPIB-command (aka GET - group execute trigger)
"""
self.adapter.connection.assert_trigger()
def reset(self):
"""
Initatiates a reset (like a power-on reset) of the HP3478A
"""
self.adapter.connection.clear()
def shutdown(self):
"""
provides a way to gracefully close the connection to the HP3478A
"""
self.adapter.connection.clear()
self.adapter.close()
super().shutdown()
|
