comparison example.py @ 64:4ca9fdf0795a

Add simple scope example
author Daniel O'Connor <doconnor@gsoft.com.au>
date Fri, 08 Jan 2021 14:10:24 +1030
parents
children
comparison
equal deleted inserted replaced
63:c90db15a497e 64:4ca9fdf0795a
1 #!/usr/bin/env python
2
3 # Copyright (c) 2009
4 # Daniel O'Connor <darius@dons.net.au>. All rights reserved.
5 #
6 # Redistribution and use in source and binary forms, with or without
7 # modification, are permitted provided that the following conditions
8 # are met:
9 # 1. Redistributions of source code must retain the above copyright
10 # notice, this list of conditions and the following disclaimer.
11 # 2. Redistributions in binary form must reproduce the above copyright
12 # notice, this list of conditions and the following disclaimer in the
13 # documentation and/or other materials provided with the distribution.
14 #
15 # THIS SOFTWARE IS PROVIDED BY AUTHOR AND CONTRIBUTORS ``AS IS'' AND
16 # ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
17 # IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
18 # ARE DISCLAIMED. IN NO EVENT SHALL AUTHOR OR CONTRIBUTORS BE LIABLE
19 # FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
20 # DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
21 # OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
22 # HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
23 # LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
24 # OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
25 # SUCH DAMAGE.
26 #
27
28 import usb488
29 import matplotlib.pylab as pylab
30 import numpy
31 import time
32
33 def main():
34 u = usb488.USB488Device()
35 print("Found device")
36
37 u.write("*IDN?")
38 print("IDN reports " + u.read())
39
40 u.write("DATA:ENC RIB") # Big endian signed
41 u.write("DATA:WIDTH 2") # 2 bytes wide
42 u.write("SELECT:CH1 ON") # Turn channel 1 on
43 u.write("DATA:SOURCE CH1") # Set the curve source to channel 1
44
45 u.write("CH1:SCALE?")
46 vscale = float(u.read(1).split()[1])
47 print("Channel 1 scale is %.2f volts/div" % (vscale))
48 u.write("HOR:MAIN:SCALE?")
49 hscale = float(u.read(1).split()[1])
50 print("Horizontal scale is %f sec/div" % (hscale))
51
52 u.write("*WAI") # Make sure the previous commands have been
53 # executed
54 u.write("CURVE?") # Ask for the curve data
55 then = time.time()
56 result = u.read(1.0) # Takes the CRO a while for this
57 now = time.time()
58 print("CURVE read took %f milliseconds" % ((now - then) * 1000.0))
59 data = result[13:] # Chop off the header (should verify this really..)
60 dattype = numpy.dtype('>h') # Big endian 16 bit quantity
61 ary = numpy.fromstring(data, dtype = dattype)
62 ary = ary / 32768.0 * vscale
63 pylab.plot(ary)
64 pylab.show()
65
66 if __name__ == "__main__":
67 main()