baud

Elixir Serial Port with Modbus RTU.

Installation and Usage

1. Add baud to your list of dependencies in mix.exs:

def deps do
  [{:baud, "~> 0.5.4"}]
end

2. Enumerate your serial ports.

["COM1", "ttyUSB0", "cu.usbserial-FTVFV143"] = Baud.Enum.list()

3. Interact with your serial port.

tty = case :os.type() do
  {:unix, :darwin} -> "cu.usbserial-FTYHQD9MA"
  {:unix, :linux} -> "ttyUSB0"
  {:win32, :nt} -> "COM5"
end

#Try this with a loopback
{:ok, pid} = Baud.start_link([device: tty])

Baud.write pid, "01234\n56789\n98765\n43210"
{:ok, "01234\n"} = Baud.readln pid
{:ok, "56789\n"} = Baud.readln pid
{:ok, "98765\n"} = Baud.readln pid
{:to, "43210"} = Baud.readln pid

Baud.write pid, "01234\r56789\r98765\r43210"
{:ok, "01234\r"} = Baud.readch pid, 0x0d
{:ok, "56789\r"} = Baud.readch pid, 0x0d
{:ok, "98765\r"} = Baud.readch pid, 0x0d
{:to, "43210"} = Baud.readch pid, 0x0d

Baud.write pid, "01234\n56789\n98765\n43210"
{:ok, "01234\n"} = Baud.readn pid, 6
{:ok, "56789\n"} = Baud.readn pid, 6
{:ok, "98765\n"} = Baud.readn pid, 6
{:to, "43210"} = Baud.readn pid, 6

Baud.write pid, "01234\n"
Baud.write pid, "56789\n"
Baud.write pid, "98765\n"
Baud.write pid, "43210"
:timer.sleep 100
{:ok, "01234\n56789\n98765\n43210"} = Baud.readall pid

4. Interact with your RTU devices.

alias Modbus.Rtu.Master

tty = case :os.type() do
  {:unix, :darwin} -> "cu.usbserial-FTVFV143"
  {:unix, :linux} -> "ttyUSB0"
  {:win32, :nt} -> "COM5"
end

#rs485 usb adapter to modport
{:ok, pid} = Master.start_link([device: tty, speed: 57600])
#force 0 to coil at slave 1 address 3000
:ok = Master.exec pid, {:fc, 1, 3000, 0}
#read 0 from coil at slave 1 address 3000
{:ok, [0]} = Master.exec pid, {:rc, 1, 3000, 1}
#force 10 to coils at slave 1 address 3000 to 3001
:ok = Master.exec pid, {:fc, 1, 3000, [1, 0]}
#read 10 from coils at slave 1 address 3000 to 3001
{:ok, [1, 0]} = Master.exec pid, {:rc, 1, 3000, 2}
#preset 55AA to holding register at slave 1 address 3300
:ok = Master.exec pid, {:phr, 1, 3300, 0x55AA}
#read 55AA from holding register at slave 1 address 3300 to 3301
{:ok, [0x55AA]} = Master.exec pid, {:rhr, 1, 3300, 1}

Development

• Testing requires two null modem serial ports configured in test/test_helper.exs

Windows

Install Visual C++ 2015 Build Tools by one of the following methods:

• Download and install visualcppbuildtools_full.exe
• Thru Chocolatey choco install VisualCppBuildTools.

From the Windows run command launch cmd /K c:\Users\samuel\Documents\github\baud\setenv.bat adjusting your code location accordingly.

Ubuntu

Give yourself access to serial ports with sudo gpasswd -s samuel dialout. Follow the official Elixir installation instructions and install build-essential erlang-dev as well.

Roadmap

Future

• Remote compile mix task to Linux & Windows
• Pass test serial port thru environment variables

0.5.4

• Updated to sniff 0.1.4

0.5.3

• Updated to sniff 0.1.3
• Document Windows/Ubuntu dependencies

0.5.2

• Updated to sniff 0.1.2 need for ´iex -S mix´ to find native library in Elixir 1.5.1
• Updated to modbus 0.3.7

0.5.1

• Updated to sniff 0.1.1
• Extract NIF to its own repo (sniff)

0.5.0

• Posix NIF implementation
• Win32 NIF implementation
• Baud api simplification
• Refactored to NIF for improved speed and test isolation
• Removed sock/loop (will be implemented as part of forward)

0.4.3

• Add wait4ch to handle non standard line/packet terminators

0.4.2

• Port proxy added to ensure proper closing on exit status msg
• Kill tests added for both baud and sock
• Refactored from genserver to actor

0.4.1

• Updated Makefile for Windows 10

0.4.0

• Added sample script (1 y 2)
• Improved documentation
• Update to modbus 0.2.0 (refactoring required)

0.3.0

• Integration test script for modport
• Added test.sh to isolate tests run
• RTU master, slave, and tcpgw loop modes
• Serial port export to socket in raw, text, and modbus mode
• RTU API matched to modbus package (1,2,3,4,5,6,15,16)
• Improved timeout handling for shorter test times

0.2.0

• Interactive RTU: read/write up to 8 coils at once

0.1.0

• Cross platform native serial port (mac, win, linux)
• Modbus (tcu-rtu), raw and text loop mode

Research

• Support udoo neo
• Support beaglebone black
• Support raspberry pi 3 B
• Assess rewriting the windows native code using the win32 api
• Assess rewriting the windows native code using c#/.net
• Split into a core package and OS dependant packages holding native code
• loop* tests still show data corruption when run all at once
• Implement Modbus ASCII support (no available device)
• Implement DTR/RTS control and CTS/DSR monitoring
• Implement separate discard for input and output buffers
• Unit test 8N1 7E1 7O1 and baud rate setup against a confirmed gauge
• Get port names required for unit testing from environment variables
• Implement a clean exit to loop mode for a timely port close and to ensure test isolation
• Improve debugging: stderr messages are interlaced in mix test output
• Improve debugging: dev/test/prod conditional output
• Move from polling to overlapped on Windows
• Research why interchar timeout is applied when reading a single byte even having many already in the input buffer. Happens on MAC.
• Research how to bypass the 0.1s minimum granularity on posix systems
• Research higher baud rates support for posix and win32
• Research Mix unit test isolation (OS resources cleanup)
• Research printf to embed variable sized arrays as hex strings