aboutsummaryrefslogtreecommitdiff
path: root/lecroy.py
blob: 31c282ee61ab1673d8bf21dfd6d2507ec419d55b (plain)
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
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
# LeCrunch
# Copyright (C) 2010 Anthony LaTorre 
#
# 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 3 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, see <http://www.gnu.org/licenses/>.

import sys
import re
import array
import StringIO
import struct
import numpy as np
import scope

# data types in lecroy binary blocks, where:
# length  -- byte length of type
# string  -- string representation of type
# packfmt -- format string for struct.unpack()
class String:
    length = 16
    string = 'string'
class Byte:
    length = 1
    string = 'byte'
    packfmt = 'b'
class Word:
    length = 2
    string = 'word'
    packfmt = 'h'
class Long:
    length = 4
    string = 'long'
    packfmt = 'l'
class Enum:
    length = 2
    string = 'enum'
    packfmt = 'h'
class Float:
    length = 4
    string = 'float'
    packfmt = 'f'
class Double:
    length = 8
    string = 'double'
    packfmt = 'd'
class TimeStamp:
    length = 16
    string = 'time_stamp'
    packfmt = 'dbbbbhh'
class UnitDefinition:
    length = 48
    string = 'unit_definition'

# byte length of wavedesc block
wavedesclength = 346

# template of wavedesc block, where each entry in tuple is:
# (variable name, byte position from beginning of block, datatype)
wavedesc_template = ( ('descriptor_name'    , 0   , String),
                      ('template_name'      , 16  , String),
                      ('comm_type'          , 32  , Enum),
                      ('comm_order'         , 34  , Enum),
                      ('wave_descriptor'    , 36  , Long),
                      ('user_text'          , 40  , Long),
                      ('res_desc1'          , 44  , Long),
                      ('trigtime_array'     , 48  , Long),
                      ('ris_time_array'     , 52  , Long),
                      ('res_array1'         , 56  , Long),
                      ('wave_array_1'       , 60  , Long),
                      ('wave_array_2'       , 64  , Long),
                      ('res_array_2'        , 68  , Long),
                      ('res_array_3'        , 72  , Long),
                      ('instrument_name'    , 76  , String),
                      ('instrument_number'  , 92  , Long),
                      ('trace_label'        , 96  , String),
                      ('reserved1'          , 112 , Word),
                      ('reserved2'          , 114 , Word),
                      ('wave_array_count'   , 116 , Long),
                      ('pnts_per_screen'    , 120 , Long),
                      ('first_valid_pnt'    , 124 , Long),
                      ('last_valid_pnt'     , 128 , Long),
                      ('first_point'        , 132 , Long),
                      ('sparsing_factor'    , 136 , Long),
                      ('segment_index'      , 140 , Long),
                      ('subarray_count'     , 144 , Long),
                      ('sweeps_per_acq'     , 148 , Long),
                      ('points_per_pair'    , 152 , Word),
                      ('pair_offset'        , 154 , Word),
                      ('vertical_gain'      , 156 , Float),
                      ('vertical_offset'    , 160 , Float),
                      ('max_value'          , 164 , Float),
                      ('min_value'          , 168 , Float),
                      ('nominal_bits'       , 172 , Word),
                      ('nom_subarray_count' , 174 , Word),
                      ('horiz_interval'     , 176 , Float),
                      ('horiz_offset'       , 180 , Double),
                      ('pixel_offset'       , 188 , Double),
                      ('vertunit'           , 196 , UnitDefinition),
                      ('horunit'            , 244 , UnitDefinition),
                      ('horiz_uncertainty'  , 292 , Float),
                      ('trigger_time'       , 296 , TimeStamp),
                      ('acq_duration'       , 312 , Float),
                      ('record_type'        , 316 , Enum),
                      ('processing_done'    , 318 , Enum),
                      ('reserved5'          , 320 , Word),
                      ('ris_sweeps'         , 322 , Word),
                      ('timebase'           , 324 , Enum),
                      ('vert_coupling'      , 326 , Enum),
                      ('probe_att'          , 328 , Float),
                      ('fixed_vert_gain'    , 332 , Enum),
                      ('bandwidth_limit'    , 334 , Enum),
                      ('vertical_vernier'   , 336 , Float),
                      ('acq_vert_offset'    , 340 , Float),
                      ('wave_source'        , 344 , Enum) )

class LeCroyScope(scope.Scope):
    """
    A class for triggering and fetching waveforms from the oscilloscope.

    .. note::

       You must call connect() on the object before fetching waveforms.
    """
    def __init__(self, host, port=1861, timeout=2.0):
        super(LeCroyScope, self).__init__(host, port, timeout)

    def connect(self):
        """Connect to the oscilloscope."""
        super(LeCroyScope, self).connect()
        # initialize some parameters
        self.send('comm_header short')
        self.check_last_command()
        self.send('comm_format DEF9,BYTE,BIN')
        self.check_last_command()

    def getchannels(self):
        """Returns a list of the active channels on the scope."""
        channels = []
        for i in range(1, 5):
            self.send('c%i:trace?' %i)
            if 'ON' in self.recv():
                channels.append(i)
        return channels

    def trigger(self):
        """Trigger the oscilloscope and wait for an acquisition."""
        self.send('arm;wait')

    def getwavedesc(self, channel):
        if channel not in range(1, 5):
            raise Exception('channel must be in %s.' % str(range(1, 5)))

        self.send('c%s:wf? all' % str(channel))

        msg = self.recv()
        if not int(msg[1]) == channel:
            raise RuntimeError('waveforms out of sync or comm_header is off.')

        data = StringIO.StringIO(msg)

        startpos = re.search('WAVEDESC', data.read()).start()

        wavedesc = {}

        # check endian
        data.seek(startpos + 34)
        if struct.unpack('<'+Enum.packfmt, data.read(Enum.length)) == 0:
            endian = '>'
            wavedesc['little_endian'] = True
            np.little_endian = True
        else:
            endian = '<'
            wavedesc['little_endian'] = False
            np.little_endian = False

        data.seek(startpos)

        # build dictionary of wave description
        for name, pos, datatype in wavedesc_template:
            raw = data.read(datatype.length)
            if datatype in (String, UnitDefinition):
                wavedesc[name] = raw.rstrip('\x00')
            elif datatype in (TimeStamp,):
                wavedesc[name] = struct.unpack(endian+datatype.packfmt, raw)
            else:
                wavedesc[name] = struct.unpack(endian+datatype.packfmt, raw)[0]

        # determine data type
        if wavedesc['comm_type'] == 0:
            wavedesc['dtype'] = np.int8
        elif wavedesc['comm_type'] == 1:
            wavedesc['dtype'] = np.int16
        else:
            raise Exception('unknown comm_type.')
            
        return wavedesc

    def getwaveform(self, channel, wavedesc):
        """
        Request, process, and return the x and y arrays for channel number
        *channel* from the oscilloscope.
        """ 

        if channel not in range(1, 5):
            raise Exception('channel must be in %s.' % str(range(1, 5)))

        self.send('c%s:wf? dat1' % str(channel))

        msg = self.recv()
        if not int(msg[1]) == channel:
            raise RuntimeError('waveforms out of sync or comm_header is off.')

        return np.fromstring(msg[22:], wavedesc['dtype'], wavedesc['wave_array_count'])