Mercurial > ~darius > hgwebdir.cgi > pyinst
view phasediff.py @ 64:4ca9fdf0795a
Add simple scope example
author | Daniel O'Connor <doconnor@gsoft.com.au> |
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date | Fri, 08 Jan 2021 14:10:24 +1030 |
parents | b6dc43e6f6f0 |
children |
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#!/usr/bin/env python # Copyright (c) 2020 # Daniel O'Connor <darius@dons.net.au>. All rights reserved. # # Redistribution and use in source and binary forms, with or without # modification, are permitted provided that the following conditions # are met: # 1. Redistributions of source code must retain the above copyright # notice, this list of conditions and the following disclaimer. # 2. Redistributions in binary form must reproduce the above copyright # notice, this list of conditions and the following disclaimer in the # documentation and/or other materials provided with the distribution. # # THIS SOFTWARE IS PROVIDED BY AUTHOR AND CONTRIBUTORS ``AS IS'' AND # ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE # IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE # ARE DISCLAIMED. IN NO EVENT SHALL AUTHOR OR CONTRIBUTORS BE LIABLE # FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL # DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS # OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) # HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT # LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY # OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF # SUCH DAMAGE. # # Expected DB schema # CREATE TABLE phasediff ( # name TEXT, # time TIMESTAMP WITH TIME ZONE, # delta NUMERIC(15, 12), # cumulative NUMERIC(15, 12) # ); import datetime import matplotlib.pylab as pylab import numpy import psycopg2 import scipy.signal import sqlite3 import sys import time # Should try this code instead: https://github.com/python-ivi/python-usbtmc import usb488 def main(): u = usb488.USB488Device() print('Found device') # See "TDS2000 Programmer.pdf" u.write('*IDN?') print(('IDN reports ' + u.read())) #dbh = sqlite3.connect('phasediff.db') dbh = psycopg2.connect('host=vm11 user=phasediff dbname=phasediff') test(u, dbh, 'delamerelts') def test(u, dbh = None, name = None): if dbh != None: cur = dbh.cursor() u.write('DATA:ENC RIB') # Big endian signed u.write('DATA:WIDTH 2') # 2 bytes wide u.write('CH1:SCALE?') vscale1 = float(u.read(1).split()[1]) print(('Channel 1 scale is %.2f volts/div' % (vscale1))) u.write('CH2:SCALE?') vscale2 = float(u.read(1).split()[1]) print(('Channel 2 scale is %.2f volts/div' % (vscale2))) u.write('HOR:MAIN:SCALE?') hscale = float(u.read(1).split()[1]) print(('Horizontal scale is %.5f nsec/div' % (hscale * 1e9))) # TEK2024B doesn't grok HOR:DIV? so hard code 10 (has 8 vertically) acqwindow = hscale * 10.0 nomclockperiod = 1 / 10.7e6 cumdiff = 0 lastdiff = None while True: ary1, ary2 = acquire(u, vscale1, vscale2) sampletime = acqwindow / len(ary1) # Compute clock periods # XXX: this is pretty noisy so we use the nominal clock period above for unwrapping #period1 = getperiod(ary1) * sampletime #period2 = getperiod(ary2) * sampletime # Compute phased difference between the two d = getpdiff(ary1, ary2) * sampletime #d = getpdiffedge(ary1, ary2) * sampletime if lastdiff == None: # First time, init variables and start again # XXX: should get the most recent cumuulative diff from the DB really.. lastdiff = d cumdiff = d continue # Difference between difference diff = d - lastdiff # Check if it wrapped if abs(diff) > nomclockperiod / 2: if d > nomclockperiod / 2: diff -= nomclockperiod else: diff += nomclockperiod # Accumulate deltas cumdiff += diff # Log / insert into DB now = datetime.datetime.now() print(("%s Cumulative: %.2f nsec Delta: %.2f nsec Diff: %.2f nsec" % ( now.strftime('%Y/%m/%d %H:%M:%S.%f'), cumdiff * 1e9, d * 1e9, diff * 1e9))) if dbh != None: cur.execute('INSERT INTO phasediff(name, time, delta, cumulative) VALUES(%s, %s, %s, %s)', (name, now, d, cumdiff)) dbh.commit() lastdiff = d def acquire(u, vscale1, vscale2): u.write('ACQ:STATE 1') # Do a single acquisition u.write('*OPC?') u.read(2.0) # Wait for it to complete u.write('DAT:SOU CH1') # Set the curve source to channel 1 u.write('CURVE?') # Ask for the curve data then = time.time() result = u.read(1.0) # Takes the CRO a while for this now = time.time() #print('CURVE read took %f milliseconds' % ((now - then) * 1000.0)) data1 = result[13:] # Chop off the header (should verify this really..) ary1 = numpy.fromstring(data1, dtype = '>h') ary1 = ary1 / 32768.0 * vscale1 # Scale to volts u.write('DAT:SOU CH2') # Set the curve source to channel 2 u.write('CURVE?') # Ask for the curve data then = time.time() result = u.read(1.0) # Takes the CRO a while for this now = time.time() #print('CURVE read took %f milliseconds' % ((now - then) * 1000.0)) data2 = result[13:] # Chop off the header (should verify this really..) ary2 = numpy.fromstring(data2, dtype = '>h') ary2 = ary2 / 32768.0 * vscale2 # Scale to volts return ary1, ary2 def getpdiff(ary1, ary2): '''Return phase difference in samples between two signals by cross correlation''' # Rescale to 0-1 ary1 = ary1 - ary1.min() ary1 = ary1 / ary1.max() ary2 = ary2 - ary2.min() ary2 = ary2 / ary2.max() # Cross correlate corr = scipy.signal.correlate(ary1, ary2) # Find peak amax = corr.argmax() return amax - (len(ary1) - 1) def getpdiffedge(ary1, ary2): '''Return phase difference in samples between two signals by edge detection''' # Rescale to 0-1 ary1 = ary1 - ary1.min() ary1 = ary1 / ary1.max() ary2 = ary2 - ary2.min() ary2 = ary2 / ary2.max() # Find rising edge of each ary1pos = numpy.argmax(ary1 > 0.2) ary2pos = numpy.argmax(ary2 > 0.2) return ary1pos - ary2pos def getperiod(ary): '''Return period of signal in ary in samples''' # Compute auto correlation corr = scipy.signal.correlate(ary, ary) # Find peaks peaks, _ = scipy.signal.find_peaks(corr) # Find time differences between peaks deltapeak = (peaks[1:-1] - peaks[0:-2]) # Return average of the middle few return deltapeak[2:-2].mean() def trend(dbh, name): cur = dbh.cursor() cur2 = dbh.cursor() cur.execute('SELECT time, deltansec FROM phasediff WHERE name = %s', (name, )) _, lastdelta = cur.fetchone() count = 0 cumdiff = 0 for row in cur: time, delta = row diff = float(delta - lastdelta) if abs(diff) > 45e-9: if delta > 45e-9: diff -= 1.0 / 10.7e6 else: diff += 1.0 / 10.7e6 cumdiff += diff #print('Cumulative: %.5f nsec Delta: %.5f nsec Last: %.5f nsec Diff: %.5f nsec' % ( # float(cumdiff) * 1e9, float(delta) * 1e9, float(lastdelta) * 1e9, float(diff) * 1e9)) lastdelta = delta cur2.execute('INSERT INTO cumdiff (name, time, cummdiff) VALUES (%s, %s, %s)', ( name, time, cumdiff)) count += 1 #if count % 20 == 0: # sys.stdin.readline() if count % 1000 == 0: dbh.commit() print(('Count %d: %s' % (count, str(time)))) if __name__ == '__main__': main()