Factory Automation with Python (Pycon 2017)

Video: https://www.youtube.com/watch?v=cEyVfiix1Lw&t=1s
Abstract: https://us.pycon.org/2017/schedule/presentation/747/

Transcript

1. FACTORY AUTOMATION
   WITH PYTHON
   STORIES ABOUT ROBOTS, SERIAL PORTS, AND
   BARCODE READERS
   Jonas Neubert
   

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2. SOFTWARE IS EATING THE DICTIONARY
   Oxford Dictionary of English, 3rd revised ed., Oxford University Press, 2010, p 626
   Gamma, Helm, Johnson & Vlissides: “Design Patterns: Elements of Reusable Object-
   Oriented Software”, Addison-Wesley, 1995, p 99
   factory (n.): A building or group of buildings where
   goods are manufactured or assembled chiefly by
   machine.
   W
   hat this talk
   is about
   factory (n.): An interface for creating families of related
   or dependent objects without specifying their concrete
   classes.
   What this talk
   is *not* about
   

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3. SOFTWARE IS EATING JOB TITLES, TOO
   International Society of Automation, isa.org
   Recruiters who fill my Linkedin Inbox without reading my profile first
   Automation Engineer (n.) Creates and applies
   technology to monitor and control the production and
   delivery of products and services.
   Automation Engineer (n.) Software engineer with
   special interest in testing and deploying code.
   

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4. CAUSING FACTORY DOWNTIME SINCE 2002
   Jonas Neubert
   Software Engineer at Tempo Automation
   slides: http://jonasneubert.com/pycon2017
   twitter: @jonemo
   

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6. Conveyor
   Belt
   

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7. Barcode
   Reader
   

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8. Pusher
   Paddles
   

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9. Pusher
   Paddles
   

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10. Pusher
    Paddles
    

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11. Pusher
    Paddles
    

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12. Pusher
    Paddles
    

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13. Sensing
    + Actuation
    + Brains
    ==========
    Automation
    

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15. Laser
    (photons)
    RS­232
    (electrons)
    

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16. class BarcodeReaderDriver:
    def __init__(self, port):
    self.port = serial.Serial(
    port, 9600, 7, 'E', 1, 5)
    def read_barcode(self):
    self.port.write(b'*')
    line = self.port.readline()
    return line.strip().decode('ascii')
    def close(self):
    self.port.close()
    def __enter__(self):
    return self
    def __exit__(self, *args):
    self.close()
    

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17. Awesome!
    An instrument driver in
    under 15 lines of Python.
    

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18. Caveats
    Serial cable only works up to 15 meters (50 feet)
    (That's 1.4% of the length of the Tesla Gigafactory 1)
    Your server doesn't have enough serial ports
    (Inspecting a single bottle for barcodes usually takes six)
    

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19. # server.py
    from xmlrpc.server import SimpleXMLRPCServer
    DEV = '/dev/cu.usbserial-AL01Z5WB'
    srv = SimpleXMLRPCServer(("localhost", 2121))
    with BarcodeReaderDriver(DEV) as driver:
    srv.register_instance(driver)
    srv.serve_forever()
    # client.py
    from xmlrpc.client import ServerProxy
    cl = ServerProxy('http://localhost:2121')
    cl.read_barcode()
    

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20. SPOILER: IN THE NEXT DEMO WE'LL LAUNCH A DUCK!
    1. Industrial automation equipment exists
    2. (pure) Python works fine for interfacing
    with it
    3. Python's “batteries” are useful in this
    domain, too
    4. … and often result in more elegant and
    efficient solutions
    

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21. Sensing
    + Actuation
    + Brains
    ==========
    Automation
    

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22. “API Docs”
    

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23. PROGRAMMABLE LOGIC CONTROLLER (PLC)
    

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24. Industrial
    PC
    Usually a simple OS (this one is Windows CE)
    Real-time kernel
    Programmed with IEC-61131
    

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25. I/O
    Slices
    Library of slices for signal types — mix and match
    Examples: 5V Digital, 0-10V Analog, Relays, Motor
    Control, …
    Each signal binds to a variable!
    

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26. VAR_GLOBAL
    DO_CONVEYOR_ON AT %QX0.1: BOOL;
    DO_CONVEYOR_REVERSE AT %QX0.2: BOOL;
    END_VAR
    PROGRAM MAIN
    VAR
    CONVEYOR_ON: BOOL := FALSE;
    CONVEYOR_REVERSE: BOOL := TRUE;
    END_VAR
    IF CONVEYOR_ON <> DO_CONVEYOR_ON THEN
    DO_CONVEYOR_ON := CONVEYOR_ON;
    ELSIF CONVEYOR_REVERSE <> DO_CONVEYOR_REVERSE THEN
    DO_CONVEYOR_REVERSE := CONVEYOR_REVERSE;
    END_IF;
    Writable
    over Ethernet!
    

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27. Python implementations of the ADS Protocol
    (Automation Device Specification)
    Wrapper around vendor supplied C library
    —
    Python implementations of protocol
    pip install pyads
    github.com/chwiede/pyads
    github.com/counsyl/counsyl-pyads
    

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28. from counsyl_pyads import AdsConnection
    from counsyl_pyads import AdsClient
    from counsyl_pyads.adsdatatypes import *
    ads_conn = AdsConnection(
    target_ip='192.168.99.25',
    target_port=801,
    target_ams='5.10.208.214.1.1:801',
    source_ams='192.168.99.1.1.1:5555',
    )
    plc = AdsClient(ads_conn)
    plc.write_by_name(
    'MAIN.CONVEYOR_ON', BOOL, True)
    

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29. Python IEC-61131 (PLC)
    business logic
    connects to services
    user interface
    signal I/O
    human safety
    machine safety
    timing critical
    little to no downtime
    part of test suite
    requires downtime
    factory tests
    re-certification?
    regular release
    schedule don't touch this
    

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30. Sensing
    + Actuation
    + Brains
    ==========
    Automation
    

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31. Start
    Noread?
    Read Barcode
    Yes
    Find Package Color
    Red or Blue?
    Left Paddle Right Paddle
    No
    Gum Color
    Database
    Blue Red
    

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32. ms3 = ServerProxy('http://localhost:2121')
    plc = AdsClient(ads_conn)
    plc.write_by_name(
    'MAIN.CONVEYOR_ON', BOOL, True)
    while True:
    bc = ms3.read_barcode()
    col = upc_to_color(bc)
    if not col:
    time.sleep(0.25)
    elif col.r > col.b:
    time.sleep(1)
    plc.write_by_name(
    'MAIN.LEFT_PADDLE', BOOL, True)
    else:
    time.sleep(1)
    plc.write_by_name(
    'MAIN.RIGHT_PADDLE', BOOL, True)
    

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44. WANT TO GET STARTED?
    Device Drivers
    “APIs for robots”
    File Formats & Protocols
    parsers, converters, viewers, …
    Data Science & Machine Learning
    vibration monitoring, predictive maintenance,
    scheduling optimization, …
    Security
    you'll be busy…
    

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45. QUESTIONS
    http://jonasneubert.com/pycon2017
    twitter: @jonemo
    packages mentioned
    pypi: pyserial
    pypi: microscan
    pypi: pyads
    github: chwiede/pyads
    github: counsyl/counsyl-pyads
    equipment used
    Barcode Reader:
    Microscan MS3
    Coneyor: Dorner 1100 Series
    PLC: Beckhoff CX 1020
    

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