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"""
Provide basic class to operate scope
Created by Eugeniy E. Mikhailov 2021/11/29
"""
import pyvisa
import scpi
import re
import numpy as np
class Scope(scpi.SCPIinstr):
"""
Do not instantiate directly, use
rm = pyvisa.ResourceManager()
Scope(rm.open_resource('TCPIP::192.168.0.2::INSTR'))
"""
def __init__(self, resource):
super().__init__(resource)
class SDS1104x(Scope):
def __init__(self, resource):
super().__init__(resource)
self.resource.read_termination='\n'
self.maxRequiredPoints = 1000; # desired number of points per channel, can return twice more
def mean(self, chNum):
# get mean on a specific channel calculated by scope
# PAVA stands for PArameter VAlue
qstr = f'C{chNum}:PAVA? MEAN'
rstr = self.query(qstr);
# reply is in the form 'C1:PAVA MEAN,3.00E-02V'
spltStr = re.split(',', rstr)
rstr = spltStr[1]
spltStr = re.split('V', rstr)
rstr = spltStr[0]
return( float(rstr) )
def getAvailableNumberOfPoints(self, chNum):
if chNum != 1 and chNum != 3:
# for whatever reason 'SAMPLE_NUM' fails for channel 2 and 4
chNum = 1
qstr = f'SAMPLE_NUM? C{chNum}'
rstr = self.query(qstr)
# reply is in the form 'SANU 7.00E+01pts'
spltStr = re.split(' ', rstr)
spltStr = re.split('pts', spltStr[1])
rstr = spltStr[0]
return( int(float(rstr)) )
def getSampleRate(self):
rstr = self.query('SAMPLE_RATE?');
# expected reply is like 'SARA 1.00E+09Sa/s'
spltStr = re.split(' ', rstr)
spltStr = re.split('Sa/s', spltStr[1])
rstr = spltStr[0]
return( int(float(rstr)) )
def getRawWaveform(self, chNum, availableNpnts=None, sampleRate=None, maxRequiredPoints=None):
if availableNpnts == None:
availableNpnts = self.getAvailableNumberOfPoints(chNum)
if sampleRate == None:
sampleRate = self.getSampleRate()
if maxRequiredPoints == None:
maxRequiredPoints = self.maxRequiredPoints
if availableNpnts <= maxRequiredPoints*2:
Npnts = availableNpnts
sparsing = 1
cstr = f'WAVEFORM_SETUP NP,0,FP,0,SP,{sparsing}'
self.write(cstr)
else:
sparsing = int(np.floor(availableNpnts/maxRequiredPoints))
Npnts = int(np.floor(availableNpnts/sparsing))
cstr = f'WAVEFORM_SETUP SP,{sparsing},NP,{Npnts},FP,0'
# Note: it is not enough to provide sparsing (SP),
# number of points (NP) needed to be calculated properly too!
# From the manual
# WAVEFORM_SETUP SP,<sparsing>,NP,<number>,FP,<point>
# SP Sparse point. It defines the interval between data points.
# For example:
# SP = 0 sends all data points.
# SP = 1 sends all data points.
# SP = 4 sends every 4th data point
# NP — Number of points. It indicates how many points should be transmitted.
# For example:
# NP = 0 sends all data points.
# NP = 50 sends a maximum of 50 data points.
# FP — First point. It specifies the address of the first data point to be sent.
# For example:
# FP = 0 corresponds to the first data point.
# FP = 1 corresponds to the second data point
qstr = f'C{chNum}:WAVEFORM? DAT2'
wfRaw=self.query_binary_values(qstr, datatype='b', header_fmt='ieee', container=np.array)
# expected full reply: 'C1:WF DAT2,#9000000140.........'
return(wfRaw)
def getChanVoltsPerDiv(self, chNum):
qstr = f'C{chNum}:VDIV?'
rstr = self.query(qstr)
# expected reply to query: 'C1:VDIV 1.04E+00V'
res = re.split(' ', rstr)
res = re.split('V', res[1])
VoltsPerDiv = float(res[0])
return(VoltsPerDiv)
def getChanOffset(self, chNum):
qstr = f'C{chNum}:OFST?'
rstr = self.query(qstr)
# expected reply to query: 'C1:OFST -1.27E+00V'
res = re.split(' ', rstr)
res = re.split('V', res[1])
VoltageOffset = float(res[0])
return(VoltageOffset)
def getWaveform(self, chNum, availableNpnts=None, sampleRate=None, maxRequiredPoints=None):
wfRaw = self.getRawWaveform(chNum, availableNpnts=availableNpnts, sampleRate=sampleRate, maxRequiredPoints=maxRequiredPoints)
vertDivOnScreen = 10
VoltageOffset = self.getChanOffset(chNum)
VoltsPerDiv = self.getChanVoltsPerDiv(chNum)
return( wfRaw * VoltsPerDiv * vertDivOnScreen/250 -VoltageOffset )
if __name__ == '__main__':
print("testing")
rm = pyvisa.ResourceManager()
print(rm.list_resources())
instr=rm.open_resource('TCPIP::192.168.0.61::INSTR')
scope = SDS1104x(instr)
print(scope.idn)
print(scope.mean(1))
print(scope.getAvailableNumberOfPoints(1))
print(scope.getSampleRate())
print(scope.getChanVoltsPerDiv(1))
print(scope.getChanOffset(1))
wf = scope.getWaveform(1)
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