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# 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'])
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